Hydraulic brake lever doesn't return after being released, dependent on weather I have a pair of second-hand Shimano ST-RS685 hydraulic brake levers / shifters. Unbeknownst to me they hadn't been used for a year and had quite a bit of dirt / grit inside, which I've cleaned to a degree (as much as I can without taking them apart).
When pulling the brake lever all the way back to the bar, it often does not return back and stays in that position. There is a cylinder thing that is pushed by the lever when you press it which moves along a channel with a slight kink in it (which ultimately pushes the fluid out of the reservoir to the pads).
When I release the lever, depending how far I've pushed it, this cylinder will either get stuck at the far end or move back very slowly and not all the way as it should. It often gets stuck at the kink. The lever also gets stuck as I think it's the cylinder thing going back that pushes the lever back. If I've not pulled it all the way, then often moving the lever back manually will allow the cylinder thing to go back to its resting position. However, if it's at the far end then moving the lever back often has no effect.
The first image shows the lever pulled back all the way with the cylinder thing at the far end of the channel (circled in red). I've also added a yellow arrow pointing to the bit that comes from the lever that pushes the cylinder thing.

The second image shows how it should normally look when in a resting position.

I haven't bled that brake yet, but I have on the other brake and that one does it as well, but nowhere nearly as bad, although it does mean that sometimes the pads slightly bind. Bleeding didn't seem to have any effect on it.
I've tried cleaning the levers as they did seem to have some grit / dirt in them and also followed this guide:

             (How To Service Your Shifters - GCN) which works for about a day or two. Then the levers seem to seize up again.
Edit: I'm still having problems. Not as serious as before since I've cleaned up the levers as much as I can, but the cylinder thing in both levers will not return fully (leaving a gap of about 15%-30% between the resting position in the channel and the cylinder), dependent on weather (I think).
Yesterday, it was about 25C here and I'd left the front of the bike towards the front of my garage where it gets quite warm. Both levers were stuck at with about a 30% gap, as described above, and while I could manually push the cylinder back, this didn't stop it getting stuck again the next time I pulled it. The bike was unridable as both wheels' brakes were being applied a fair amount. Later on in the evening, when it had cooled down considerably, they were working fine, leaving virtually no gap on releasing the levers.
Today, it was hotter, but I'd put my bike in a cooler spot. The result was that they both were getting stuck with about a 15% gap. Bike would have just been ridable but with a lot more resistance than normal. Later on when it cooled down, again this problem had largely resolved itself.
Has anyone encountered this?
Further edit
I cleaned them again with compressed air and put PTFE lube in the levers (Triflow) and then greased the moving parts. Thought they were behaving better, but they're doing it again today (24C and sunny). Again getting stuck at about 30% in the channel.

I think you should try a bleed.  We could go back and forth all day about what could be causing the problem, but it will all be moot until we have ruled out air in the hydraulic system.
I had a pair of brakes (only one actually) that one day just went totally slack.  Literally fine one moment, and dead the next.  I was convinced there was a leak.  Why else would it go from working to not working so quickly?.  I asked the guy at the LBS how to go go about diagnosing and fixing the leak.  He suggested I bleed first, with out assuming a leak.   I bled the brake...problem solved... no leak after many miles of riding.
The moral of the story here, as it was explained to me by my friendly LBS guy is that when we are having trouble with anything it is advisable to proceed with typical maintenance procedures before we go looking for things that are broken. This will often take care of the problem.  If it doesn't solve our problem, our time is not wasted because the maintenance is something we would want to be doing anyway.


Do your legs get tired faster when riding a recumbent trike compared to a upright bike? In my quest for getting as much information as I can before configuring my recumbent trike, I was thinking if my legs would be get more tired as they are in a horizontal position?

In an upright bike, my legs would be "resting" on the pedals as they are on top of them.

In the recumbent trike, my legs would be in a horizontal position and my thighs would have to keep them up as well as providing the power to do the pedalling.

Are my assumptions correct?

I'm not a pro rider and have never used clips on any bike.  Even on your upright bike you train your legs and feet to stay where they're supposed to... if they just relaxed they'd fall off the pedals no matter which bike you're on.  I've been riding my recumbent for almost 3 years now and have little interest in riding anything else, though it did take a week or two to get the "new muscle groups" factored in.

Once your legs get used to the new position, as Adam mentions, I doubt you'll get any more fatigue or whatever than you did previously.  I find it less fatiguing for my legs since it takes less effort to go the same distance or speed on the 'bent (less wind resistance etc.)

The worst thing I had to get used to was the lack of ability to "stand up on the pedals" for quick jack-rabbit starts or climbing hills.  That took a bit of getting used to, including getting very intimate with my derailleur shifting.  The first few times you stop without gearing down for the next takeoff teach you quickly to avoid stopping without downshifting at all costs.  Climbing hills, you just go through the gears more instead of standing up and pumping to get "over the top".  I'm not a fast rider by any means but I find I can keep up with and occasionally pass upright riders who pass me on straight and level but run out of steam as they climb hills closely in front of me.  I haven't ridden for extremely long distances (I normally drive the first part of my 32 mile commute and park the car and ride the last 7 miles to and from work) but I have ridden the entire 32 miles several times without problems of any sort keeping the feet on the pedals.

When coasting down long hills (I cannot keep up with the pedals over ~26 MPH) I have no trouble keeping the legs and feet in proper position as I rip down the hills.


Brakepads are burning tyres out I have a Jamis Allegro Sport Hybrid (6 months old) and has gone about 400 miles so far. Today I had an accident (in the UK) because the rear tyre got punctured after hitting a good size pothole. I took it to Evans Cycles (UK) and they did a quick repair job to fix the puncture. However, the repairman pointed out that the brake pads are burning the edge of my tyres and this is very strange to me. Is there any way I can use special brake pads so that I don't have this problem?

P.S. I use Shimano DuraAce 7700 style brake pads which are apparently very cheap.

Please advise.

I've linked to some images:
Image1,
Image2-tyre_worn_out,

Edit:
From the comments and answers, this seems like the most relevant picture:

Get your toolbox, get the 5mm Allen key and align the pads yourself. Make sure they are parallel to the rim and don't touch your tyre when in braking position.

5 minute job. Saves you tyres and pads.

Update re pictures: Thanks for posting the photos - makes it easier to identify the problem. It seems that your pads are not rubbing the tyres. The problem looks like it's in the pads themselves. These pads are the cheapest possible ones. And they are glazed up. I would just replace them for better ones. Or you can take the wheels off, get some sand paper and sand top layer off the pads. This will work, but it is likely that the pads will do the same again pretty soon.

Another reason for this appearance - the brake arms are not correctly set up and one of the pads is dragging on the rim all the time, hence "burning sensation". This can be corrected by adjusting the spring: on the side of the brake arm should be a bolt - play with it, until the arms are coming to the rim at the same time.

Or if the brakes stop you well enough and don't drag on tyres/rims, just ignore them and keep riding - not a major problem.


Prevent trouser damage when biking? I am biking nearly every day to work and back (~ 3 km), but my trousers get damaged quite fast due to the created friction between my legs and the saddle. Which then means that I have to buy new ones rather frequently. Is there any way to prevent that?

Saddle in question:

Jeans and similar trousers wear fast on saddles. This is partly the seam on the inside of the leg, which is more of an issue on thick, high-friction fabric. They're also not very comfortable for riding in, especially if they get wet (including from sweat). Sitting in wet clothes when you arrive isn't much fun either, and smart stuff doesn't like being rained on.

My solution on commutes over about 8 km (5 miles) is to get changed. This also means I don't get chain oil on anything that matters. I'm not suggesting lycra as a default for commuting; apart from anything else pockets are useful at the ends. Gym shorts are good in summer, but in winter I suggest quick drying hiking trousers, and cheap ones at that. The pair I relegated to bike commuting have done a few thousand miles/km without noticeable wear.


How did my inner tube get folded in a Z inside the tire? My rear tire was keep going flat while riding, so I felt around the tire for any punctures or abnormal ‘signs’ that may be causing the problem.
One area felt too thick, and at first, I thought I just overinflated it and somehow the air got trapped. Later, I ended up pushing my bike into the rocks, and when the tire tread came off, I saw that the inner tube had literally folded up into a ‘Z’ shape inside the tire. How did this happen? I have never seen anything like this before.

Most likely incorrect tube and tire combo. Check your tube range if it matches the size of your tire. Could also be that you seated the tire incorrectly.


What are "M14/125" pedals? While looking for replacement pedals for my old French bike, I've come across products which are labelled as having thread size "M14/125". Does this denote the "traditional French" threading of 14*1.25mm?

Yes, this does.

Another option is to re-thread the cranks if you take it to the right bike shop, and then install a standard pedal.


Will a bicycle trailer damage my (steel) bicycle? I have a rhode gear trailer with a 100 lb capacity, similar to the burley and other brands, that attaches to the left chainstay (see image of hitch below). I currently have it attached to my heavy-duty commuter, and I am not concerned with any adverse effects that it might have. However, I am having so much fun with it that I would also like to attach it to my road bike, which has a steel frame built for racing.

I accept that this can affect the paint, but I don't want to cause structural damage (e.g. bend or break) the frame. Should I be concerned?

Thanks!

These hitches don't work very well. They don't grab tightly enough, so they can twist around the bar and bump in to the wheel. As they twist they will take off the paint. They also require a lot of turns to attach and remove.

I had two trailers with this kind of hitch, and 3 bikes to pull with. I bought this Burley flex connector for each trailer:

I used this kind of hitch:

It works pretty well, but on one bike it's slippery, so the quick release lever can turn a little even when tight. But not enough that it's going to make the wheel fall out. Also, on one bike it bumps in to the QR, so I have to put it in just the right spot.


Dura Ace 7800/7900 vs 9000 I have Dura Ace 9000 mechanical shifters and I'd love to have hoods that aren't black.  The only product I've found are Hudz but they only fit 7800 and 7900.  Obviously there was enough of a change between the 7800s and 7900s to warrant a new mold, but does this apply to the 9000s too?

Yes, different. There's at least one company doing colorful ST-R9000 hoods.


Can I replace a Shimano FC-MT500 26/36 crankset with a Shimano Ultegra FC-R8000 36/46 set? On my Kross Level 10.0 MTB (2x10) used mostly on dirt roads and pavement I find I never use 1-10 and seldom go below 15th but I need more top end speed. Wondering if the Ultegra would be a straight swap out?

Thanks!

Unfortunately no, the Ultegra crankset is not compatible, nor is any other road Shimano crank designed for a Hollowtech II bottom bracket (assuming this is your bike).

The issue is that there are MTB and Road versions of Hollowtech BBs. MTB ones fit in 68 or 73mm shells, using 2 2.5mm spacers on 68mm ones. Road BBs only fit in 68mm shells. MTB BBs are therefore 5mm wider than road ones. Road crank axles are 5mm shorter than MTB cranks, and are only long enough for road BBs.

If you have a 68mm BB shell you could put a road BB in it and fit a road crank but the chainline would be way off.

You could look for larger aftermarket chainrings in the Shimano asymmetric 4-bolt pattern, but you have to deal with chainring clearance issues Andrew Henle described in his answer.


Is there any reason not to use a 9mm solid front axle hub in place of a QR hub? I've got my hands on an old dynamo hub, with a view to building a 700C dynamo front wheel for my hybrid.  It uses (I believe, and will check) an M9 solid axle, but the existing one is QR.  It certainly fits without being loose, but I don't have the nuts for it and it's built up with an ETRTO 590 rim at the moment so I wouldn't have any brakes for a test ride.  I already use security QRs so I'm not bothered about having to undo nuts to take the wheel off.

Is there a reason to avoid doing this, or anything I should check before ordering parts?

The only potential caveat is many solid axle hubs come with toothed axle nuts that are good at chewing up dropout surfaces, particularly aluminum or carbon. On "nice" bikes it's always best to just use track nuts if possible to preserve the frame while still getting good clamping force, or washers at the least.


Why is the rear wheel of my tandem bike skidding? We have recently bought a tandem and the rear wheel skids out when riding. Any idea why this happens?

Comment below: When we are riding along in a straight line and there is an uneven surface it does this a lot. The heavier rider is on the front of the bike.

The captain's weight hardly pushes the rear wheel down at all, while the stoker's weight is almost completely on the rear wheel, so check their weight is positioned correctly. If the stoker is standing up, this can shift weight off the rear wheel, making a skid more likely. Standing up on tandems is "advanced", some would add "insanity".


Is there a master link for single speed chain that will fit in Shimano chain tensioner? I've got a bike with planetary hub Shimano Alfine 8-speed and this chain tensioner. It uses single speed chain. However master link on the chain I bought (similar to this pic) is too wide to fit in the chain tensioner. Is there another master link that will fit? Where do I buy it?

Edit: I made a mistake when I purchased chain with 1/8 inch width, my cog and everything else are made to work with 3/32 inch chains.

Assuming you have a new KMC chain (pic of the connector is KMC).

KMC definitely makes 1/8" chain connectors of the 'Missing Link' style without the extra side plate clip that is presumably causing problems.

See here: http://kmcchain.us/connectortype/single-speed-ml/

and here: http://www.kmcchain.eu/connector-bmx_track_fixie

Can't tell you if those are readily available in Russia or where the best place to buy them is.


Suggestions of a good video on intermediate Mountain Biking skills: getting up (and down)  1' obstacles I'm looking for a good training video on intermediate mountain biking skills.
(I've been mt biking for about 12 years and I'd like to improve my skills.)

I'm looking for a video that really breaks the skills down and maybe provides suggestions of drills to practice.

I'm looking for DVDs or online videos (YouTube, etc.).

Update:

Skills I'm looking for:

Getting over 5" to 12" tall obstacles (rocks, fallen trees).
Manual Wheel lift (which would probably help with the above).
Jumping /Descending down something really steep (2' drop off, etc.)

It isn't included on your list, but the motion used for bunny hopping applies. I watched the following a while ago and thought it was informative:

For 'getting up', you can combine a manual and bunny hop. What I normally do when approaching an obstacle that I want to hop over, is shift my weight back, then pull up on my wheel (just before reaching the obstacle). Getting your front wheel up is accomplished by pulling back evenly with both arms while making a hard pedal-stroke (you'll need to be in a small enough gear). Right before your wheel(s) come in contact with the obstacle, 'un-weight' your rear wheel and gently push your bars forward. Even if your wheels don't leave the ground, once you learn to un-weight your rear wheel, you'll naturally ramp off the obstacle, even if it's square like a curb. With practice you'll eventually start hopping before you contact the object.

If you have trouble putting it all together, try not to get frustrated. It can take a while to develop the co-ordination and strength required to complete each motion. I find that one of the best ways to ease your learning experience is to ride your local trails with riders that are a bit better than you. Watch what they do and try to follow their lines when you're comfortable. Pay particular attention to 'how' they ride certain obstacles/corners/descents.


I'm looking for a part that connects the saddle to the body frame of the bicycle I recently removed the saddle because it was squeaking a lot, then I cleaned the inside and put oil back in, however I couldn't re-attach the bar under the seat to the body frame, then I used this clamp probably in the wrong place and then the hex bolt threaded so I can't get it off.

The bike is a Carrera Subway 2. I should get a new seat anyway, but how can I attach a new saddle and bar thing to the body frame? I don't know what's supposed to screw into here to hold the bar and the saddle in place.

Its a bit unclear what you did or what the problem is. I presume you are having problems reinserting the seat post into the frame. From the above diagram, the seat post slots into the seat tube, and is held in place by the seat post clamp (not labeled).

I also presume hex bolt 'threaded' means you cannot undo the bolt in the seat post clamp. This clamp has to come off to insert the seat post.  My first attempt would be to try to knock it off with a hammer and screw driver by tapping gently around the circumference and 'walking' it up the seat tube. A bit of heat might help. However if the bolt is tight I would not bother.

If that does not work you should be able to cut the bolt with a hack saw blade in the slot, and remove the clamp. An alternate is to drill the bolt head off or cut the clamp itself. New clamps are readily available so do not worry if you damage it.

Once the clamp is off, the seat post should slide fairly easily into the frame, set the height and tighten the new clamp (not too much).


Is it possible to fit a chain guard to a bike with derailleur gears? I've been slowly going through the process of converting my old hardtail mountain bike into a commuting bike. One of the things that I'd like to do is to fit a chain guard so that I can ride the bike while wearing long trousers and not have to worry about chewing up the trouser cuffs.

A complication is that the bike (like most mountain bikes) is fitted with both front and rear derailleur gears. I'm not keen to replace these with an internally geared hub system as I have been trying to keep the changes relatively modest in their cost.

Are there chain guards that you can add to bikes with derailleur gears?

SKS Germany - a company that make great bike products, including the fenders that I put on two of my bikes, make a product called the Chainboard - a chain guard designed to accommodate front derailleurs.

I don't have one, but you can google SKS Chainboard and find several reviews.


Hybrid e bike suspension or no suspension I am 64 and just taken up cycling again after a very long lay off. I ride purely for leisure and a mix of tarmac, canal tow paths and old railway tracks. Having looked at a number of e bikes i am getting confused as to the best ones to shortlist.
Considering the Boardman HYB 8.9e (no front suspension) or the Scott Axis 20(front suspension). Obviously getting hold of any bike at the moment is a challenge but I am seriously leaning towards the Boardman as it is lightweight and would put bigger tyres on to compensate for lack of suspension. Any help appreciated. BTW. I am about 175lb and 5ft 10'

I would definitely not consider suspension on a hybrid bike for 2 reasons.

A suspension fork typically has very little to offer on the type of terrain you would ride a hybrid on.  A high quality high volume tyre (ideally tubeless) with a supple casing will do a great job smoothing the ride.
At the price point of most hybrid style bikes suspension forks are typically heavy with poor small bump sensitivity and poor adjustment options.

Rather than a suspension fork (or not) i'd be far more concerned about other features like tyre clearance, tubeless compatible rims and in the case of an e bike battery capacity.


Bike is shifting on its own Ever since I got my bike (Surly Long Haul Trucker), it has been prone to shifting on its own.  This is almost guaranteed to happen when I stand up on the pedals, and happens regularly when sitting as well.  I have the feeling that this is a dangerous condition.

It seems from reading about the problem that it is due to the cable catching somewhere and creating a clutch effect.  (read about it here)
There does not seem to be a way to adjust the friction of the shift lever.
I've tried:

greasing the cable guide under the bottom bracket (no effect)
backing off the tension of the cable with the tension knob on the cable casing (no effect)

Can anyone relate how they overcame this?  My next step is to further loosen the cable by adjusting the connection to the derailleur?

Neil is right, most all "auto shifting" or "ghost shifting" is the result of cable-tension problems.
If the cable is a bit loose, the derailleur will try to shift "up" to a smaller cog.  If too tight, it will try to catch the next larger cog.
Cables stretch, especially after a short period where the new cables stretch to the point they're stable.  after that, they should be good for a long time.
Try this.
Shift to the highest (smallest) cog and try to pull the derailleur cable away from the frame.  If there's a lot of slack, it's too loose.  If it feels very tight....
With either condition, make sure the shifter is in the highest position, and loosen the cable at the derailleur and then pull it snug.  Re-tighten the securing bolt and run it through the gears; it should be very close.
Ideally, the chain should jump smartly to each cog both up and down, and seat solidly on the cog.
If it's just a bit off, you can play with the barrel adjuster either at the shifter or at the derailleur.
Another cause of such problems is a bent rear derailleur "hanger", the part that the derailleur attaches to.
Some of these are very soft aluminum and can be easily bent.
Make sure the derailleur cage is exactly parallel to the cogs and the hanger is not visibly bent.


Are small radially laced motor hub wheels like Swytch trash? I saw a bike that recently had this kit installed on it, and was surprised at the radial spokes:

From having done rebuilds on 20" motor hub wheels, I can appreciate the temptation to look at going radial. Otherwise, even at 1x, correcting the spoke line at the nipple to avoid built-in stresses takes some careful work. The default angles are extreme, the space you have to work in is limited, and it has to be done at just the right point in tensioning to do it well. Getting it physically laced up is also somewhat challenging, which is probably enough in and of itself to make low-quality manufacturers look for alternatives.
I can also appreciate that with the spokes being so much shorter, forcing them to resist torsional loading in a radial pattern is less of an issue than it would be on a full size wheel. But this is a hub motor. Is there any possible way the math here to choose radial is sound? Or was this just a mistake, or a willfully cynical design?

This is a poor design that can work due to several properties:

On an electric bike, only part of the load is supplied by the motor. Most of the load is still actually supplied by the pedals. Thus, this should be not considered a primary motive propulsion device but rather a hill assist device.

An electric assist provides continuous torque. In contrast, the cyclist pedaling provides an oscillating torque. So if you ride 50 meters upwards on a 8% grade hill (625 meters linearly), the cranks would probably rotate about 140 times, meaning there's 280 power strokes and thus 280 load cycles. However, an electric assist would create only one load cycle in this hill.

The hub flanges are large. The larger the flange, the better the system is able to withstand torque. Optimally the spoke pattern should probably be 1-cross or 2-cross, in which case there is already a large effective "torque arm" to create the torque. On a radial wheel, the effective "torque arm" is created by the hub flange rotation with respect to the wheel rim. Creating such "torque arm" on radial wheels of course affects the tensions of all spokes (tightening them), so I would expect the wheel to fail in a very short amount of time, unless stress relieved. However, stress relieving the spokes could make them withstand the amount of time it takes the buyer of the "electrification kit" to realize the kit might not be such a good idea and purchasing the electric Brompton from official source would be a far better idea.

Thus, the design is marginal. It will probably last few thousand kilometers. It could last few tens of thousands of kilometers if using the lowest assist level and if the weight of the cyclist is low.
I wouldn't buy it.


Can the extreme heat from powder coating influence frame integrity of older bikes? I just got an older frame powder coated.  The shop that I took it to doesn't specialize in bikes.  They mainly do industrial grade powder coating and perhaps a car wheel here and there, so I wouldn't consider them the most knowledgeable people when it comes to handling frames.  The frame is lugged steel.  Could the heating process influence the frame's integrity?

No, 400F will not affect frame integrity.


Replacing bearings in pivot links I'm replacing all bearings in pivot links on my full suspension bike and for one of them seems to have more space around bearing itself (housing? if that is right term). I can pop it out and insert it back without using any tools (7 other bearings had to be press fitted). Should I worry about this 'loose' bearing, can I fix this issue by applying Loctite? (Can I use blue Loctite 243 for this or I need stronger grade?)

"Bore" or "bearing bore" are the words I know for it. Yes, you're right to worry about this, especially if it's actually more or less loose in there and not just a slip fit. One possible negative consequence of the fit being loose is the bore could get deformed and/or ovalized until there's knocking or play you can feel while riding as a result. It could also creak. It probably also doesn't help bearing life, and I'm sure there are other problems that could result from this depending on the factors at work. If it's more like a slip fit, where it's somewhat snug but can be pushed in and out by hand, that's fairly common and while not ideal, it's unlikely to do much more than creak, although having it develop into something worse isn't impossible.

The common fix for this is to use Loctite 609 or equivalent, which is designed for this kind of application. It expands to create a tight fit, but generally not so much you'll hate life too much when you have to get it apart. I wouldn't be optimistic about the medium-strength threadlockers like 243 being strong enough here.


Brake system replacement Currently I have a Tektro Auriga brake system. I don't like the Auriga brakes at all, so I decided to replace them with Deore XT BR-M800.

At front I have 180mm disk and between the caliper and fork is an adapter. I'm curious about the rear caliper. Will the new caliper fit without an adapter with a 160mm disk?
Here are pictures of my current brake system.(couldn't upload directly due to image sizes)

If the rear Auriga used no adapter for a 160mm rotor, the new M800 won't need one either.

Post mount frames can be understood to have a "native" rotor size, the size of rotor that a caliper works with when mounted without an adapter. For some bikes that size is 140, which would mean you would need an adapter, but it's mostly road bikes where you see that, not a hybrid or mountain bike that would be more likely to come with the brakes you have. Likewise some rougher stuff MTB bikes start out at 180 in the back and can't run a 160.


1972 Schwinn 10 speed missing chain need to know how many links I just bought a vintage Schwinn Suburban 10 speed bicycle but the chain was missing from the bike. I need to know how many links is generally on this bike. I bought a bike chain that says for 5/6/7/8 speed bike chain. for bikes with 5-8 rear cogs. this bike being a 10 speed has 5 rear cogs and 2 front gears. I counted the links and it has 111 total links and 1 connecting link. I need to know if I need to shorten this chain before installing onto bike, or will it fit just as it is?

There are two different techniques used to size a chain for a multi-speed, derailleur bike.  The specific one to use is based on the number of teeth the largest cog of the freewheel has. One method is used if the large cog has 27 teeth or less, the other method when the large, rear cog has more than 27 teeth.  On a bike like you describe, with a five speed freewheel, the largest cog will have 28 teeth or less.

First method for bicycle with a rear cog having >27 teeth: WITHOUT going through the rear derailleur, wrap your new chain around the large front chainwheel and back and around the large rear cog bringing the two ends of the chain together.  Essentially you've now wrapped the chain around the large-large combo, eliminating the rear derailleur. The chain ends will come together and you should note an overlap of a few links.  The properly sized chain will be +2 links (that would be 1 inner link and 1 outer ink of the chain) past the point where the slackless, wrapped chain comes together.

The second method should be used if you're sizing the chain when the large rear cog's teeth number 27 or less.  In this instance, you'll wrap the chain around the larger chainwheel and around the SMALL rear cog.  You must thread the chain through both derailleurs so it's necessary to have them (and therefore the shifters) in the correct position (large front: the inner shift cable will be under tension, and small rear, where the rear's inner cable is under little to no tension).  With the chain wrapped as described, you will bring the ends of the chain together (note that you'll be pulling one side of the chain against the spring tension of the rear derailleur which will create movement of the derailleur's cage/pulley wheels).  Continue to bring the ends together and overlap until the the rear derailleur's cage is straight up and down.  More properly stated, the correct chain length is achieved when a line drawn through the center of the upper guide pulley wheel and lower pulley wheel is 90 degrees to horizontal.  Please refer to the diagram on page 28 of the following link:

Shimano General Operations.
Page 28 deals with chain sizing on road bicycles having two front chainwheels and multiple rear cogs.  Keep in mind that your connecting link is an outter link and that you'll eventually join your sized chain where each end is an inner link.


Confused about frame size I am trying to determine the right frame size for myself before purchasing a hybrid bike. My height is 174 cm and I have an inseam size of 85 cm. If I go by the height it should be a medium frame between 43-47 cm but if I go by the inseam height, recommended frame size is 58 cm! Apparently, the latter is wrong but I wonder why there is so much difference between two calculation methods.

Unless your body proportions are very unusual, I would expect two different calculation methods to produce similar results. But yours aren't. You're slightly taller than me, with slightly longer legs.
First, I'm curious where you found these two calculation methods.
Second, different manufacturers size their bikes differently. Bikes are sometimes sized by their "virtual" seat tubes, that is, the seat tube is extrapolated to a point where it meets a horizontal line extended from the top of the head tube (this is a holdover from when top tubes were horizontal, and seat tubes really were that long). Sometimes they're sized by the actual seat-tube length, and I've even seen one or two manufacturers size their bikes by top-tube length. So if you found one calculator at one manufacturer's site, and another at another's, you shouldn't expect they'd produce the same results.
My own guess based on your inseam is that you'd fit a 56-cm bike (using "virtual" seat-tube sizing), so 58 cm isn't far off. For a hybrid that has a significant slope to its top tube, I wouldn't be surprised if the actual seat-tube length were in the range of 43–47 cm.


Doing track stand while sitting? I have been trying to do "track stands" while sitting down. Standing up makes it harder to balance and doesnt feel right.

Is it possible to do a track stand while sitting down? Should I just stop trying this and learn to do it the right way?

This reminds me a bit about how I didnt use the "home row" to touch type for a very long time, then I concentrated on "doing it right" and was surprised by how easy it was to learn.

I probably don't do "proper" track stands since I don't ride a fixed gear bike, but if you can find a bit of a hill at a stop then you can kind-of-sort-of do a track stand (you pedal up the hill and let gravity pull you back down). Sometimes the crown of the road is enough…

That said, I always sit, I didn't know you were supposed to stand, so I'd say keep working on it!


Cable routing and why is there no optimum solution This is a general question, regarding the routing of the cables of both brakes and derailleurs on a frame.

I find it highly practical to mount all cables along the bottom of the top tube. This offers the following advantages:

The wide down tube protects the cabling from mud and gravy, originating at the front tire
The top tube can support weight e.g. sitting* there or supporting luggage.

What are the reasons of the other cabling schemes? I am most puzzled the combined scheme "2 cables on bottom of the bottom tube + 1 cable on top of the top tube".

* one of my pleasant habits is, when there are no free seats in the park and the grass is wet, sitting on the front tube, with the bike tilted, one hand on the brake and the other holding a beer

What are the reasons of the other cabling schemes?

Most Cyclocross bikes will route all the rear cables along the top of the top tube. In a cyclocross race, you will get off and shoulder your bike, the cables would get in the way on the underside of the top tube. Many CX bikes have a flat bottom top tube as well for easier shouldering. Routing the cables along the top keep them cleaner too, cyclocross races get muddy and if they put the cables on the bottom of the downtube, they would get very wet, muddy and allow grime into the housing.


Changing arm length for DUB crank My bike has a 175mm crank arm (https://www.sram.com/en/truvativ/models/fc-styl-6k-b1) on a Specialized Epic HT (https://www.vitalmtb.com/product/guide/Bikes,3/Specialized/Epic-Hardtail-Expert,27186)
I think the important words are (don't know their meaning): boost, threaded, dub,
Now I want to try shorter arms 170 and even 165. Since I don't know exact length I'd like, I'd like to try cheaper ones if I can, try them first and buy a more expensive one once I decide the arm length.
I read DUB cranks are compatible with any existing BB (https://www.mbr.co.uk/news/product_news/sram-dub-370517). What I want to know is if dub BB is compatible with non-dub cranks?  Otherwise my options are pretty limited to SRAM cranks it seems.

No, DUB cranks are not compatible with any existing bottom bracket.
DUB is the deign of the crank spindle and the bearings in the BB. A dub crank only fits in a dub bottom bracket. It’s possible to get DUB bottom brackets that fit in many different frame bottom bracket shell standards, that may be where the confusion originates.
If you want different cranks you either have to get DUB compatible ones, or replace the bottom bracket along with the crank. There are many different crank and bottom brackets that fit in a threaded bottom bracket frame shell. If you choose to go with non-DUB cranks, you will have to deal with other compatibility issues such as getting the proper crank chainline. You’ll also need some special tools or a repair shop’s help to un and re-install the bottom brackets.
In your position, I would look for a used SRAM DUB crank that is a drop-in replacement for your current one; possibly one in rough condition or missing the chainring that is relatively inexpensive. If you do not like the shorter arms you will be able to sell it for approximately what you purchased it for.


Need Hidden nut for SRAM Force 1 chainring I purchased a 50t Force 1 x-sync chainring.  The SRAM install instructions say to place the hidden nut (thin item that has "teeth" on the outside that becomes "permanent" in the chainring once installed) on the hole marked "Crank here for hidden bolt".  Unfortunately the chainring I have did not have this label on it so I put it in the wrong hole and only noticed later.  I managed to knock it out again but it isn't really a part that is intended to be re-installed, so I want a new one.

I can't find anywhere that sells this part.  I can't even find the part number in SRAM's parts catalog.  Also, annoyingly, most chainrings seem to come with this nut already embedded in the chainring so this problem is not widespread (mine came in a bag along with the bolts and washers needed for the chainring).  Its a super small thing - like 2 mm deep.  Threaded on the inside, teeth on the outside that grip the hole edges.  Seems like a terrible design because if those teeth fail the part will just spin along with the bolt and you'd never get the bolt off.  There's no slot on it (like used on other chainrings) so using the special chainring bolt slot tool doesn't help.

Can anyone tell me what this part is formally called (ideally a part number), and possibly any place that will sell it? Even better - is there a superior alternative (preferable steel)?

The official Sram part number is 11.6918.000.001 , those are said to work on the RED and FORCE models. That is the number for the hidden bolt set anyway. I also read that someone spoke to Quarq and they advised him to pop it out of the old ring and use it for his new ring which he also stated worked just fine, so you may save yourself $20.


how do I paint a bicycle chain? I've seen chains with so many colours, white, red, you name it.

I would like to give it a try (this paint job is intended for visual styling of the bike, nothing related to protecting it), but I have no clue on how to do it.

I think there must be a way to paint it without "glueing" the links with paint, I don't know if spray paint does that or not... I'm sure I need to degrease it first, but then what follows?

So, the question:

How do I paint a chain without ruining it? (the painted chain needs to be in working conditions, it will be used).

I think @freiheit already said it: paint the outside of the outer links!

If you ride single/fixed, this part of the links never touch anything else, so the paint does not wear out neither damage other working parts.

I would do it degreasing the chain very well (boiling with soap in the end, perhaps) and then using a hard foam paint roller, with the chain over the ground with its side facing up.

If you don't mind paying for the job, most the colored chains I've seen in google seem to be powder-coated (electrostatic) or anodized. This would give a probably good result, but I think you wouldn't want to pay the price :oP


How can I fix brake pads being too tight even after pushing the pistons back in? I just got delivery of a road bike with SRAM Red disc brakes. It was delivered with little inserts in the brake pads to prevent accidental squeezing of the lever when the rotor was not in.

When I put the wheels on, I noticed that the pads were too tight on the rotor even in the released position, so they were rubbing heavily (not because of misalignment but because of being too tight.)

So I did what I read online:

Removed the wheel
Removed the brake pads
Gently used a flat-head screwdriver to push the pistons back in (the best I got was so that they were flush with the body of the brake caliper)
Put the pads and wheel back on.

Unfortunately, when I squeezed the brake lever again, I could feel that the feeling got firmer and firmer for 2-3 squeezes, until, again, the brake pads would not recede from the "braking" position, and be in contact with the rotor at all times.

What can I do to fix this?

My avid brakes had the same problem and it was due to too much fluid in the system, to solve the problem :

Remove the pads and keep them away from any oil (fluid).
Unscrew the bleed screw a little and put a towel on it
Push the calipers back completely

4.Clean calipers well before reinstalling pads.

Be aware that the amount of fluid that will exit should be a drop or a little bit more.
Let too much fluid exit and you will have to rebleed them, so do it gradually.

This is a common problem on new avid sram brakes.


How does dynamo hub feel at hand? I am 100% new to the dynamo world, and after unpacking it I was surprised how it behaves. I already googled and found out that some of my worries are "normal", but for some of the issues observed I didn't find explanation (or "it is normal" confirmation).
I am talking about just hub, I didn't build a wheel yet. I am holding/squeezing axle nuts at one hand, and try to turn hub body with the other.
When I hold hub at hand and try to turn it there is a lot of friction, there are distinct points (some like stop points) where hub feels click-in (there is not audible click). Far, far analogy but it resembles the rear hub somewhat -- there is also some friction and there are also some special points.
Friction in dynamo hub I have is much greater. Gathering from all "it is normal" I take my hub is not broken. Yet.

But there is more -- the rear hub movement is predictable, I turn it by hand, the hub has no inertia so it stays exactly when I stop turning it, in other words any point/angle is valid point/angle. With dynamo hub if I am less than midway between points it bounces back by itself. So there are only X designated points/angles at which it can rest. And as for friction -- forward turning is hard, turning it backward is even harder (at first I thought it is not possible at all).
So my question is -- is this "more" section above normal as well, or those are odd even in dynamo-hubs world and I probably have broken hub (or terrible quality one)?

Remember a dynamo hub has a small electric generator inside of it. What you are feeling when you turn the shaft is the interaction between the magnets and wires in the the generator creating peaks of torque on the shaft.


Road bike frame for offroad/cx wheels I'll be moving in the near future from a wide open rural area with open, expansive country roads to a more suburban area with traffic issues but a few offroad trails available for riding. My question -- and probably a silly one -- is: is it at all recommended to outfit a separate set of wheels with CX tires for my road frame for trail riding at a fraction of the cost of a new CX bike or am I putting my road frame at unnecessary risk trying to save some money?

I'm not imagining I'm going to be getting into legit mountain biking (just yet) and only ride for personal fitness and the enjoyment of it.  I've seen threads here asking the opposite (CX for Road), but nothing this way.

Thanks!

Personally, if your road frame is an out-and-out road bike - I would say you will be faced with several issues.

strength of your frame

Not only will this stress your frame - it may also fatigue the frame. And may cause sudden and catastrophic failure.

tyre clearance

Most road frames will not take a tyre greater than 28mm. Some no more than 25mm.

comfort

The seating position and reach could be altered to make more comfortable - but it will always be a compromise.

Geometry

Road bikes have different geometry to CX bikes. Lower bottom bracket offers lower clearance, steeper head angle makes the ride more twitchy.


Titanium seatpost in steel seat tube, good idea? I want to use a titanium seatpost in a frame with a steel seat tube (Columbus Spirit tubes). Is it a good solution? I want to understand if the metals play well from a structural point of view, and I also want to avoid seizing between the two metals.

More in general, is there some reference on which materials I can combine together in the seat zone?

Carbon seatposts likely produce the most vibration damping

There have been at least two lab tests of vibration damping in seatposts. One, by Bike Radar, tested five brands of carbon seatposts. The second, by Velonews, tested 14 seatposts, including carbon, aluminum, and titanium. In addition, the Velonews test included one traditional suspension seatpost (i.e. the Cane Creek Thudbuster), plus a few other seatposts designed to offer significant flex (e.g. a Specialized seatpost with elastomers). The Bike Radar lacked traditional suspension seatposts, but had some seatposts in the second category (i.e. non-traditional, low-travel suspension posts).

Generally, posts with saddle setback offer more damping. Carbon posts also offer more damping. The Velonews test only included two titanium seatposts, both from one manufacturer (Moots). That said, the titanium posts had slightly more damping than aluminum posts. Also, the more seatpost you have exposed, the more damping you may get (this appears to vary by seatpost model).

In general, do note that lowering your tire pressure can provide additional vibration damping. I do not know if testers have quantified this in relation to how much you might gain from a different seatpost. To answer your question, titanium might not provide much more vibration damping than an aluminum seatpost. It probably won't provide less damping. If your saddle position allows it and this is important to you, you might want to think about getting a setback post. If you must change your seatpost, you may be better off considering a carbon seatpost.

Most generally, use grease to prevent seizing

For anything titanium, i.e. titanium seatpost and/or frame, the general recommendation is to use anti-seize. I have been trying to find out what anti-seize is and why it is recommended for titanium. I believe anti-seize may be ordinary grease with additives like copper, nickel, or other substances. Titanium is prone to galling, i.e. adhesion between sliding surfaces like screw threads or seatposts. To be honest, it still is not clear to me why grease alone does not suffice to prevent galling. Nevertheless, it appears to be commonly accepted wisdom to use anti-seize on titanium. Thus, I have to keep recommending that you do so.

Anti-seize can contain copper, but it can contain other minerals instead. For example, Park Tools' anti-seize is aluminum based. I commonly see copper anti-seize recommended for titanium. I can't find any information on why copper is best for this application. There may not be any substantive reason.

For aluminum or steel seatposts in aluminum or steel frames, standard grease suffices. Oddly enough, per the Wikipedia link, aluminum is also prone to galling, and it would seem to call for anti-seize as well. Nevertheless, conventional wisdom appears to be that an aluminum seatpost in any frame with grease is fine, provided you periodically (usually at least annually) regrease it.

For carbon fiber frames and/or carbon fiber seatposts, the answer is also standard grease. If the seatpost slips, you can use carbon assembly paste, which is grease with compounds that add friction. There appears to be a myth that grease harms carbon fiber. In fact, I was about to write just that, but while searching for sources to back up that assertion, I found that Lennard Zinn, a technical writer for Velonews, and Craig Calfee, who makes carbon bikes, both have said that grease is fine in carbon frames or on carbon posts.


How to reduce vibrations to handlebars on aluminium road bike Question: How can I reduce the vibrations to the handlebars on an all-aluminium road bike?   Either to the rider's hands or to the camera, or both.

I have been riding an all-alloy road bike for the last couple months, and while its so much faster than the MTB its terribly tiring.

I've suspected that its a harsh ride because there are lots of buzzes and rattles that come and go with different road surfaces.

A recent night ride demonstrated the problem in pictures.... I have a gopro on the stem and here are some comparison shots.

Example Smooth Here's some tarmac which is less than a couple months old.  Its really nice on which to ride:

Example Buzzy Here are two stills cropped to show lights at night.  The road is chip-seal which is quite common locally.

A video at night time was no good, but here's a short clip showing the buzz in sunlight.

Hand interface  I've tried

Padded Cycling gloves - helped a little with the hands, but they were cold.  I've been wearing my full hand cycling gloves with no padding.
Hand positions - I'm 99% on the hoods, either near the bend or up on the brake hoods.  I never use the drops, they're out of reach, and the tops only occasionally.  On a long ride I might put hands on top of the brakes for some variety ("high hoods")
Bar tape - I've fitted some bar tape which is labelled as "cork" but was really a diamond-shape of firm foam.  This helped, but the hand position is now unnaturally squishy.

Yet to try:

A shorter stem, the old one is 120mm long.  Finding one is difficult because its an odd sized quill stem.  Still searching.
A replacement front fork of steel or carbon ?  Seems like an expensive solution for an older bike.
Lower tyre pressure helps, but I'm over 100 KG so I can't really go lower than 100 PSI on 25mm tyres.
Replacement bars ?  Would carbon bars be any better at damping the vibrations?
Other suggestions?

Camera mount  I've got one of these on my stem.  There's a layer of dense foam underneath which helps a little.

There are other mounts like this one, but they have no vibration take-up mechanism, so I'm leery about dropping money on them.

Searching web sites like instructables.com has returned steadicam-type mounts for hand usage, but not for biking.

Summary: How to reduce the road buzz that is transmitted through the fork/frame/stem and the handlebars?

I have an aluminium bike with a rubber dampener built into the handle bar, it's part of Specializeds range, not sure if there are general versions.

A suspension fork would iron out more bumps than a carbon one, but may not fit your bike.

I've taken videos from a handlebar mounted camera too and I think there will always be a lot of jolting that is impossible to dampen. Low light will make this worse.

I think the best answer is to use a helmet mounted cam, so the suspension system is your body and neck. I've seen some fantastic videos of the New York alley cat races and they all use helmet cams. They also need strong necks!

How much image stabilization can your camera provide?


broken hub dynamo lights 80s Triumph Trying to fix up my 80s Triumph bike which has a Sturmey Archer 3 speed dynamo hub. The hub has two screws which connect to two cables. I think the hub generates an AC supply and powers a front and rear light.

Here are some photos:

http://imgur.com/a/TYcoM/all

So the things I'd like to achieve are, to:

1) identify the bulb so I can purchase two new ones

think i may have found them! My lamp says 6 volts, 0.1 amps which i
worked out as 6 volts and 0.6 Watts, maybe this one will work??.

2) be able to run an AC supply though the circuit to see if it works at all

3) see if the dynohub can generate an AC supply

Would a multimeter help?

4) to find the name of the small metal plates that connect the wires to the screws on the Sturmey Archer hub

I think they might be called hook connectors but not sure how to wire them up

Any help would be much appreciated. I've fallen at the first hurdle and cant even identify the bulbs!

Basic troubleshooting steps

1) Is there power coming from the dynohub?  Use a multimeter on AC 6V (possibly 20Volt setting required on a standard meter)

2) Is the power capable of flowing to the lamps?  Use a meter on continuity-beep or on resistance setting to check.

3) Does the lamp fitting carry power to the lamp?  Same as #2

4) Does the lamp work?  Use continuity or resistance test again.

Replacing the wire is a good idea if it looks manky, and new lamp holders will give you more light for the same input.  The hub is the most expensive part.


BB spindle length/chainline for re-used Shimano FC-M391 chainset I'm trying to rebuild an old Univega MTB. Primary goal is to build a good or decent bike from used parts.

The crankset+bb that was on the bike when I got it was really worn out. I unscrewed it and cleaned the frame carefully. I asked around and found a friend that had a Shimano FC-M391 crankset with its original BB I could get.

When I installed it I just noticed that the new BB axle was ~10mm longer than the one I removed from the Univega. Unfortunately I didn't measure it but I guess it's 123mm. The original from the Univega was 110,6mm.

The new crankset doesn't come close enough to the frame. From what I can see I would like to have it ~10mm closer? I think I got it to come up all the way on the BB-axle.

I thought the BB axle length was specified with the crankset? I looked in the Shimano docs where it says 123mm.

What width should I use for this bike?

The spindle length depends on your frame and on the used crank. The combination of those two will dictate your chainline which should be 47.5mm.
In some cases it can be 47.5-50mm ( see https://www.sheldonbrown.com/chainline.html )
There are also chainlines for other types of bike, the 47.5mm are for Mountain Bikes.

You can measure your current chainline and then calculate the spindle length you need based on the current chainline and spindle lenghth. So for example if you now got a chainline of 52.5mm and need 47.5mm your BB spindle should be 10mm shorter to achieve this.


How do I adjust my rear derailleur (Shimano SIS) when it is only slightly out? It has been a while since I had my bike serviced and the gears are sometimes slightly out of perfect alignment. This results in the occasional mis-shift.  I also think the change in seasons have played a part.
What do I need to do to get it back to perfect?

Adjusting the rear derailleur is a matter of tightening or slackening the shifter cable so that the chain runs smoothly for all rear cogs.  The easiest way to do this is using a barrel adjuster -- there's normally one where the cable runs into the derailleur and you may have another where the cable runs into the shifter or on the downtube for a road bike.

If you look at the barrel adjuster from the point of view of the cable housing (not the bare cable) running into it, turning the adjuster clockwise will slacken the cable and counter-clockwise will tighten it.  Adding slack to the rear derailleur should adjust the chain towards the small cog, tightening moves it towards the large cog.  If the barrel adjuster doesn't give you enough range, then you'll have to adjust the slack where the cable clamps into the derailleur.

With your bike in a stand, or flipped upside-down, change to your middle chainring (for a triple) and try it out.  You should be able to see small movements in the derailleur as you tweak the barrel adjuster.  I like to get the middle cog dialed in really well (change gears in/out this cog) and then check that this setup works for all of the others.  You'll probably have to adjust this slightly once you ride the bike.  (Once you get comfortable with this, you can actually tweak the derailleur mid-ride without stopping if you have a barrel adjuster on the shifter or down tube)

After tweaking the derailleur setup, you should also double-check the limit screws just to be on the safe side.  These are two screws on the derailleur that adjust how far it can move.  One keeps the chain from going past the large cog (sometimes marked L?) and the other does the same for the small cog (H?).  Make sure that the derailleur cannot move the chain off of the end cogs.  Turning the appropriate screw clockwise should push the limit in towards the center of the cassette, counter-clockwise normally gives the derailleur more freedom.

Of course, there are a whole range of other problems that can affect shifting (worn chain, worn cogs, bad chain line, worn cable/housing, sticky derailleur, etc.), but try this first.


What other tools do I need with my truing stand? I just got a truing stand but the manufacturer seems to do a good job of advertising every other accessory under the sun to go with it.  What are the essentials? A wheel dishing tool?  Tension meter etc...?

I'm looking to just true wheels.

If you're just truing a wheel, all you need is the appropriate spoke wrench (which depends on what wheel you have, obviously).

There are four aspects to truing a wheel (quoted from Park Tool, which I suggest you read):

  LATERAL TRUE: this true is also called “rim run-out”, and is the
  side-to-side wobble of the rim as the wheel spins. This aspect is the
  most critical to brake caliper settings.

  RADIAL TRUE: this is the amount of up and down wobble. If the wheel
  becomes out-of-round, it wobbles up and down with each revolution. In
  severe cases this will affect brake pad placement and can be felt by
  the rider as a bump every wheel revolution.

  RIM CENTERING or “DISH”: this refers to the rim being centered in the
  frame. If the rim is offset in the frame to either side it may be
  difficult to adjust the brakes. Severe cases of poor centering can
  also cause handling problems, because the rear wheel will not track
  behind the front wheel.

  TENSION: this is simply the tightness of the spokes. Spokes are
  tensioned just like other fasteners. Spoke tension is best measured
  using a tool called a spoke tension meter (tensiometer) such as the
  Park Tool TM-1, which flexes the spoke using a calibrated spring.

You probably won't need to handle dishing a wheel at home. As for the tensiometer, it can be nice to have (esp if you're replacing spokes or whatever; large deviations from normal spoke tension) or if you get into building a wheel, but a lot of people go by feel (squeezing spokes or whatever) and it is adequate.


What is this chrome BMX? ]1
Serial #236777. Lots of GT components. Blue plastic rims. Probably the original tires.

Bog-standard BMX, probably Chinese, likely from a department store. The brake is a touch fancy but nothing else is remarkable.


Headset bearings open to closed type My XC MTB has open type headset bearings, is it possible to replace them with closed type?

The main problem is that I live in a flat and only place where to wash my bike after a muddy or dusty race is self-service car wash nearby. that results in sands being pushed into headset bearings and I have to clean them basically each time I wash my bicycle.

You will very likely be able to buy a new, sealed bearing headset for your bike. Without more information I can't tell you any more than that. It's not a particularly difficult job for a bike shop, but it can be tricky if you don't have the right tools.

Also, as pointed out in the comments, "sealed bearings" are better at resisting water and muck, but they're not waterproof and definitely not water-jet-proof.


What type of bicycle frame is this? Need help with identification. If anyone knows what kind of bike has the rear fender built in to the frame, that might help.

What pieces I can deduce from the looks of it.

It was designed for a single speed drivetrain.
No mounts for rim or disk brakes means it was likely meant for a drum rear brake
Ashtabula cranks mean it was old and/or cheap bike.
A curiously shaped "integrated" rear fender means the bike was unlikely to be designed to take part in competitions. Most likely it was a cruiser/utility/novelty bike.
Judging from relative diameters of head and seat tubes, it likely took a 1 inch fork, but it is hard to tell.
Wheel size as well as frame size are unclear as no reference measurements are provided. I can guess it was designed for wheels from 20" to 26".


How can I find the perfect handlebar height? I test-rode a bike (2018 Specialized Rockhopper Sport) and I liked everything except the height of the handlebars, and it's the XL size so there's no larger option available.

I feel like it would be more comfortable if the handlebars were higher, but I worry that I may raise it and feel like it's too high or realize that my discomfort was caused by something else.

For seat height, I know that when I put my heel on the pedal my leg should be straight, but is there some easy rule like this for determining the perfect handlebar height for me?

Also, will it be difficult for me to experiment with changing the height up and down after buying the bicycle? Does raising the handlebar height require just moving spacers around or do I have to change the stem with a different one?

Raising handlebar height is very easy to do, but you may need parts.

There are a number of ways to raise a handle bar. You can also move the seat forward, use a shorter stem or narrower bars to get a similar effect.  Note however than any change can have an effect on handling of the bike.

No parts ways:
Spacers: If there are spacers above the stem, put these below the stem.

Seat: Moving the seat forward will have raise your torso.
With riser bars you may be able to rotate them, depending of sweep.

Narrower bars - you can trial narrower bars just by moving the grips and shiftier/brake levers inboard. If you like it, you can cut the bars down. The current trend in MTB's is wide bars and short stems, so its almost certainly possible to go narrower.

Parts way:

Stem - stems are very easy and quick to swap. When buying a bike, the shop should be prepared to swap stems around and let you try til you find one you like. To get yourself sitting higher, a steeper angled and/or a shorter should be tried.

Bars - raiser bars are a good way to go, they come in various heights.

Stem riser - these bolt onto the steerer tube and effectively increase the length


Could I add chain rings, front derailleur, and shifter for the front derailleur from other bike? I have a bike that has only one chainring and no front derailleur (obviously).

Could I take the chainring set, front derailleur and shifter from another bike and put it on my bike?

My bike never had a front derailleur and is 7 speed currently.

Maybe.

Here are the issues:

Shape of the seat tube. If the seat tube is not cylindrical or too wide near the chainrings you wont be able to mount a band clamp derailleur.

You have a 3 piece crank with crank arms separate from the bottom bracket axle, with a square taper type crank-axle interface. If the multi-chainring cranks you want to mount are the same you can mount them also.

Getting the right chainline. Different cranks have the rings at different offsets from the square taper hole, and require different length axles to position the rings correctly. If the chainline is the same on both bikes and the axles are the same length then you can make a direct swap, otherwise you'll need to calculate what length axle you need and get a new bottom bracket.

Chainstay clearance. The single front ring bike may not have enough clearance for a multiple chainring crank.

Front derailleur cable housing mounts. If your frame does not have `em, you'll need an alternative. I believe there are ones you can clamp to you frame available.

You'll need a new chain as the required chain length will be longer (assuming you are adding a bigger chainring).

You'll need to check that you rear derailleur has a great enough total capacity Otherwise it will not be able to handle the increased variation in chain slack. Capacity needed is (difference in size smallest-largest sprockets) + (difference in size smallest-largest chainrings)


Can I convert the brakes from rim to disc I have a 1990s vertik 2 it's the mountain bike one and I am wondering if I could convert the rim brakes to disc brakes if so what are good budget options

No.

You would require new wheel hubs with a disk rotor mount, and you would need a fork and a frame with caliper mounts.

Once you replace the fork, frame, and wheel hubs, its not economical.

Instead, shout yourself to some new rim brake pads.  Good kool-stop ones will improve your braking and it feels like a decent upgrade, for much cheaper.


Why Are The Fingers Attached On Some Cycling Gloves? What is the purpose of the material connecting the fingers on some pairs of cycling gloves?

It's used to pull the gloves off without them going inside out. Don't pull too hard, or they will rip.  A gentle even pull should be enough to remove the gloves.


How much mountain biking experience is needed for Goat Canyon Trestle Bridge via Carrizo Gorge Road? Goat Canyon Trestle Bridge via Carrizo Gorge Road is a 16mi round trip out and back trail that I guess runs along some disused train tracks.
My question is: how much mountain biking experience is needed to do this trip?
I could hike it but that would be one of the longest single day hikes I've ever done. I ride bikes on sidewalks and paved roads, from time to time, but I've never mountain biked before.

I am unfamiliar with that route.  However you say its an "out and back trail" so you'll be coming back the same way you went in.
Simply evaluate the terrain on the way in, and if you think its going to be beyond you on the way back, stop there.
Disused train tracks are normally almost flat - trains can't climb a grade any steeper than about 1.5% on plain rails, so as long as it wasn't a cablecar or cogged funicular railway, then it will be essentially flat.  If the route leaves the track bed then that no longer applies.

Note that there are descriptions and text in the link you posted

As of December 2020, some of the tunnels are closed, but detours are provided.

Warning: Users have reported that this trail is located on private property and you may be subjected to fines. It is recommended that you do not park on the dirt roads.

Hikers report that the first and third tunnels are closed and one is also gated off. Both of those closed tunnels offer detours.

So that closed tunnel is why the elevation record in your link shows some 10% grades, probably the detours up and over the closed tunnels.
And there's a tag of no shade so its going to be hot and dry.  Pack sufficient water as well as the usual necessaries.
Basically - if you find something that you feel is beyond you, stop and return.


how to replace a bearing on BB7800? Friends,

Do anyone of you know on how to replace a bearing on BB7800 ?
Do I need a special tool ? or a screw driver, and hammer would be enough to push it out ?

Thanks

The Dura-Ace BB-7800 is designed to be replaced as a cartridge unit. Replacing the bearing in the cup, without replacing the cup, would be difficult, if not impossible without damaging the cup.

These bottom brackets are exceptionally cheap, and really don't have much to them beyond the bearing, and the threaded cup to hold it in the frame.

Why spend the time and effort to replace only the bearing?

If you want to replace the whole cup cartridge, you need a 5mm allen key, a 3/8" drive torque wrench capable of 40Nm, a 1/4" drive torque wrench capable of 12Nm, The Shimano Hollowtech 2 BB cup tool, and the Hollowtech 2 BB bearing adjustment tool.

Procedure here from Shimano on PDF.

Video of general procedure here.


Why use embrocation versus just oil? Many cyclists apply embrocation cream to their legs in colder weather because it makes them feel warmer. I understand wanting to have an extra "weather-barrier", in the form of the oil(s) that make up the majority of embrocation. However, the ingredient that causes the "warming" feeling in embrocation cream, capsaicin, is a vasodilator. In the long run, wouldn't that lead to colder legs, seeing as it would expose more blood to the colder temperatures at skin level?

Wouldn't it be better to just use oil (without capsaicin) to get the "barrier" effect, instead of embrocation cream? Are there any studies indicating that embrocation (or topical capsaicin) improves performance in colder weather?

Interesting question! Embrocation sounds very gimmicky to me but I don't race. I wonder if the effect is like drinking hard liquour when you're cold, which a lot of ppl think warms you up. In reality alcohol is also a vasodilator, pushing blood to the surface of your skin and making you feel warmer. This is contrary to what your body is trying to do in cold weather, which is maintain core temperature.

So arguably, vasodilation could be a good thing in a controlled and not-too-cold scenario, e.g. cycling in cold weather, where you want your muscles and skin warm, and are not concerned about hypothermia. But it's probably to be avoided in seriously cold scenarios, although at such times you're probably no longer relying on embrocation for warmth but instead full-on thermal leggings or snow pants.


Shifter cable broke down: misuse, lack of maintenance, shifter or regular occurrence? My rear shifter cable just snapped yesterday. It broke down without any real warnings that I can recall. It neatly broke right at the head, that remained inside the shifter (a Shimano one).

If I recall correctly, it already broke last year but as I don't do much distance I wonder if this is normal. I had the cable changed at a local shop, and I must say I don't know which cable they put in, but it seemed quite cheap.

I isolated a few possible causes:

I shift too often/too many gears at once. As I ride the bike in a city I tend to quickly shift down when approaching a red light, and back up when it turns green. Should I instead remain in an upper gear and use more strength to get going ? Or maybe just shift the front gear once ?
I don't really put any maintenance effort in the shifter, should I maybe grease it from time to time? Especially since the bike is parked under a shed, but not in a closed garage.
Maybe the shifter itself is damaged, I bought this bike from second hand, it has visibly suffered a few falls, but the external damage is minimal.

Or is this a perfectly normal occurrence ?

It's not uncommon. Some Shimano shifters are prone to breaking off near the head in the shifter and it can be a bugger to get that little bit out of the shifter. My wife has Ultegra 9sp and I have to replace her cable about every 12-18 months.

She can now tell when it's beginning to fray because the shifting gets dodgy before it completely breaks.


Changing SRAM Rival brifters to flat bar - which hydraulic brake levers? I've got a gravel bike, the Planet X London Road, with SRAM Rival 1x11 groupset.

I'm thinking of converting it to a flat bar.
From what I have read, any SRAM 11 speed shifter should work, as the cable pull is the same, but I don't know how best to handle the hydraulic disc brakes.

Is there a lever that I can just plug the existing hydraulic hose into, or will I need to replace the whole hose from caliper to lever? Is there a specific model of lever I need to get?

any SRAM 11 speed shifter should work, as the cable pull is the same

Sorry, that's not the case. SRAM MTB 11 speed uses 'X-Actuation' pull ratio (3.48mm / shift) whereas road 11 speed uses 'Exact Actuation' (3.1mm / shift). See here for extensive documentation of cable pull rations, sprocket spacing etc.

However, SRAM makes trigger shifters for at least the Force groupset.


Choosing chainring configuration I'm interested in how I would choose a chainring configuration, supposing I was either replacing mine or building a new bike for a similar usage.

I have a 50/39/30 triple chainring (& 10-speed cassette) on my Bianchi Volpe.  Rivendell sells a 46/36/24, with the argument that 50 is overkill, and if you're going to have a granny gear it should be smaller.

I buy that argument, but I spend 90% of my time riding 39 in the front and 15/17 in the back.  If I downgraded my middle to 36, then I'd have to ride smaller cogs in the back, which means it'll wear faster (I do ~2500 miles per year of city riding).  If I use the 46 then I'd be almost cross-chaining to get the same ratio.

So it sounds like this configuration would be bad for me.

However, I think a 46/30 double might be perfect.  That would pull the big ring in closer so when I'm riding on the bigger cogs in the back I hopefully wouldn't be cross-chaining.  It would wear slower because I'd be on more teeth.  I do a moderate bike tour about once a year and the 30 has worked fine for me so far (haven't done any mountains, but have done some steepish hills).

Does my rationale make sense?

There is a question here, it's just hidden in a misleading focus on details.

How do you choose chainring setups?

You need to analyze the gear ratios and speeds that you ride at and figure out the correct
overlap for your riding. The way that I've found most useful to do this is to chart the gear ratios vs speed and use an error bar to represent the speed at a given rpm.

What you want to avoid is having to "double shift" (i.e. shift both back and front) for the
speeds that you typically ride at. IMHO, cross chaining is not an issue for modern gear. It
does absolutely no harm. However, double shifting gets to be very awkward.

As a rough guide if your typical speed is 25 kph, having a couple gears higher and lower
on the same chainring at the rpms you find comfortable would be a good setup. A lot depends on what range of rpm you find comfortable to ride. A poor setup is one which
you have to double shift to get the next gear either higher or lower.

Having done a bunch of graphs and played with both triples and compact doubles over the years. I think if you are going compact double, you need to be able to do most of your flat/slightly rolling climbing in the big gear. And for somewhat average cyclists I agree with your reasoning. A 46/30 and something like 12-27 in the back would be a good replacement for the typical road triple.

46/30s are made, just very hard to find.

Velo Orange 46/30


What road hub makes the least amount of noise What brand rear hub and cassette has the lowest noise level for a road bike ?

In my experience, the most silent combination has been Shimano freehub and cheap cassette with pinned together cogs. The one I have is XT, but road hubs below Dura-Ace have similar mechanism. A cassette with loose cogs can vibrate more freely and is louder.

Other brands that I have been riding myself or have had the joy of listening on group rides include Campagnolo/Fulcrum, Chris King, Mavic, DT Swiss and so on. All of these have their own distinctive rackets.

As described in comment, completely silent roller clutch hubs have been produced. They have other, more serious problems.


Disc brake keeps making ping-like shudder I have a commuter bike with Tektro MD-285 hydraulic disc brakes. I commute about 14 miles every day (7 in, 7 out) in most types of weather, but I am not a performance cyclist by any means. It's just a good way to get to work. For the past few months, I have had a bit of a squeal and a shuddering noise that I can feel through the handlebars on the front brake when I brake it hard. When slower there is really little to no noise. I cannot for the life of me figure out what is going on. Here is what I have tried:

Sanding down and cleaning new pads and rotor.
Getting new pads and rotor and going through the bed-in process.
After replacing, pushing the pistons back in on the brake to try to ensure they are parallel and the whole pad is hitting the rotor.
Made sure the headset was not too loose.
Checked the AL fork for any cracks.

Any other ideas? Worth bleeding the brakes?

Replaced the brake and all is well. My guess is one side of a piston was being pushed out with more force than another.


Front derailleur not shifting up I have a road bike with shimano front derailleur and dropped shifter. For weeks my front derailleur has been very stiff, requiring much force on the shifter to go onto the bigger ring, so the other day I decided to look inside the shifter. Presumably because of months of 'forcing' the shifter up a gear, the circular rotating bit of plastic which the end crimp of the gear cable slots into was pretty mashed up.

So I purchased a new shifter of the same make and model and installed it (new cable too), but shifting up a gear still takes a lot of force; actually, it doesn't shift at all now. I can move the derailleur directly with my finger and thumb, with what feels like not much effort - I say that with caution because I'm not sure how hard it should be to move it manually. But it moves smoothly at least.

I've clamped the cable to the derailleur, on the smallest rung, as tightly as I can but still no luck. Any ideas?

Did you replace the housing as well? It sounds like the derailleur is working fine and the problem is somewhere in between the shifter and the derailleur in the housing.

To fully diagnose the problem, you'll need to start at the shifter and work through each section.

First test just the shifter, disconnect the cable and remove the cable from the housing. Does the shifter move easily now? You'll need to pull a bit on the cable to simulate the spring tension from the derailleur.

If that is smooth, repeat the test with the cable in the next section of cable housing. Eventually you'll find where the friction is happening.


What BMX Frame Do I Have? Restoring a BMX i got maybe in '96-'97. I bought it off a friend and its a chromoly frame and has the serial number stamp on the front head tube on the frame (0950921035). It looks "close" to an '85 GT Performer. but has some small differences. I want to restore it. How can I find this info?? THX!

It's a "power lite"

Look where the back wheel mounts, (rear dropouts?) and there might be a "p" marked right there but not always.


Short inside leg body: smaller frame? I have a bit of a disproportionate body. I am 176cm (5'9") tall, but my inside leg height is only 76cm (2'6"). I want to build a fixed-gear bike and I am looking for a frame of the right size for me. The plan is to use it to commute. All the track frames I could find are either low-pro, or with small backward sloping. And most of them are very compact, which means the top tube is short compared to the seat tube, which really doesn't fit my body. Of course, it is very hard to get a tailored track frame for a good price.

The only solution is then to buy a small frame and use long components (stem, seatpost). Is this a good solution or you can think of something else?

Track frames in general are designed for manouverability, not stability or comfort. This does not make them very good commuter bikes, but if you absolutely need a track frame you know what you are getting into. Extra long stem tones down the twitchiness a bit, but also moves the weight distribution towards front wheel.

Another solution would be buying a road frame with horizontal dropouts and not installing a rear brake. This will get you a top tube that is only moderately short related to your body, but would lose some credibility (if it was 2007, this is 2017 and track bikes are old news anyway).


How to wash a bike helmet properly? What is the best way to wash a bike helmet?

The straps are getting a bit rank from sweat and I'd like a better alternative to just hosing it down.

Rather than any complicated method or products, I do the following:

Take it with me when I shower.
Lather up hair with my preferred shampoo.
Loosen straps and fittings, place helmet on head and move and squish it around a bit to distribute the shampoo.
Rinse
Repeat.

Shampoo or body wash works great.  Then I just clip the straps over a line to hang the helmet to dry.


How to select a tube? Hi I got a used bike and my experience with bikes is very limited. The tires and tubes are all broken so I need to get new ones. I found these tires: http://www.fahrrad.de/continental-speed-king-set-26-zoll-draht-362100.html

and I found these tubes for the tires: http://www.fahrrad.de/fahrradteile/reifen-schlaeuche/rcp-fahrradschlauch-26-zoll-universal/285443.html?eqrecqid=be78e9d1-f097-11e3-804f-c8600056a33a

but when I select the tubes the website asks me for the kind of valves I need. How to select that? Should I select the valves according to a criteria or should I get any valves?

Some rims have a small-diameter drilling for presta valves, so a schraeder (car-type) valve won't fit.

If your rim is drilled for schraeder valves, you can use presta valves, but you should use a plastic adapter sleeve to hold the valve in position and avoid wear to the valve stem or the edge of the drilling.


How to assemble this headset? I bought a new threaded headset for my old steel winter beater bike, but it is slightly different from the current one and I am not sure about the correct order and orientation of the parts. I placed the bottommost one on the left.

Is this the correct order?

Without knowing the exact model of headset you're installing it's difficult to give a confident yes, however it looks correct. From left to right you have a fork crown race (this gets pressed onto the fork), two head tube cup and bearing assemblies (see below), upper race/dust cap (installed directly onto the upper head tube cup assembly), and finally a lock nut (this should be installed above any spacers you may use). The orientation of the parts in the first photo appears correct as well. If you've never installed a headset Park Tool have an article on servicing threaded headsets and Sheldon Brown has an article going over headset types and service procedures.

The only unknown is if the two head tube cup assemblies are identical (ie, can be swapped freely) or if there is a specific upper and lower assembly. There should be markings on outer housing or something in the installation instructions to help identify which is which if they came as an upper/lower pair. You may also find that only one fits snugly into the dust cap and the other is loose which would indicate which one to use as the upper.


Is SLX FD 675-B front derailleur appropriate for my bike? It seems I've made a few 'tiny' errors when choosing components to upgrade my bike. The biggest issues I'm facing at the moment are crankset and front derailleur...

Bike is Eyble Psych 4 Black Edition (full suspension, 26" wheels) and I'm upgrading various (all) Shimano components to SLX. Because I'm not very familiar with all aspects of MTB geometry and compatibility of parts - I've put myself into weird position.

I've chosen M677 crankset (2x10, 22-36t) which (if I get things right) dictates position/hight of front derailleur (SLX 765-B, 2x10, clamp type). I've installed FD provisionally and found out that it sit quite low on seat tube (seat tube is with top pull cable routing). FD clamp is almost touching the joint of seat tube, downtube and chainstays (which are asymmetric) and it could interfere with movement of rear end of bike. (I didn't put chain yet and I tried to compress rear shock all the way - and I didn't notice that FD is hitting anything.)

Anyway, I'm worried if this setup is right and should I continue installing other parts? If this is horribly wrong - what are my options regarding another FD (please recommend proper FD type) or (preferably not) changing other components?

PS. I know I should have informed myself better before buying things :D

I wouldn't feel too bad about getting the wrong FD here. This is a very easy mistake when ordering a bunch of stuff for an unbuilt bike. Maybe there was a spec sheet available somewhere that advised against low clamp for your frame, or maybe not.

You shouldn't run that FD because, suspension clearance and any other issues aside, you've mounted it as low as it can go and there's still way too much vertical gap between the cage and teeth, shown in your first pic. That really shouldn't be more than the recommended 1-3mm. It will want to throw the chain, and the designed-in contact points with the chain and cage will likely be off. (Likely because the derailer does have some forgiveness there to accommodate the chain/FD angle changing based on what the suspension is doing, but starting with it way off is still likely to cause problems).

You also absolutely should not run it if it can contact the frame at any point in the suspension travel, or threatens to. When in doubt, test it definitively by fully deflating or unbolting the shock so you can freely check the rear end movement.

You need a high-clamp/bottom-swing FD, FD-M676 if you want to stay on-series.

Confusingly, once upon a time high-clamp/bottom-swing was the norm, and then low-clamp/top-swing came along to solve problems with suspension designs that were coming out, usually involving the seat tube not being there to clamp to. Now top-swing has become more the default, and other types of mounting problems bite you instead.


Replacement for a Suntour Superbe front derailleur I broke my front derailleur trying to adjust it. It's on a 1980's Klein Performance road bike.

Should I try getting only the same one, or is there any replacement that could work well in its stead?

I love the bike, and the metal looked cheap after breaking so I don't mind trying an upgrade.

TIA

Suntour Superbe parts were great, but they have been out of production for decades, and in any case, technology has marched on. Finding a direct replacement part might appeal to vintage enthusiasts, but there's no need to do so for functional reasons. New front derailleurs may have a slightly shorter maximum "throw" because chainrings are spaced closer these days. I don't know whether this would affect you, but I'm guessing not.

One quirk of the Klein is tubing diameters that were at the time considered oversize. As best as I can determine, Klein seat tubes had a "normal" diameter of 1¼", which is a good fit for the clamps on modern front derailleurs, but I would double-check that just to make sure.


shimano fc4400 double chainring replacement I am looking to replace my Tiagra fc4400 52t chainring, however it seems to be out of stock everywhere.

Based on the parameters (130BCD, 52t) I found a few alternatives, however all of them are 10 speed.

Also, I am not sure I can put them on the same 4400 crank, as it seems the new chainset's connecting sides are slightly wider. Would it simply be a visual mismatch, or can I expect any installing/usage problems?

If the 5700 chainring is not usable on this chainset, is there another you could recommend?

Thanks!

BCD is the key, Shimano 9 and 10 speed chainrings are interchangable. Dropping a couple of teeth is not a problem, just adjust the front derailleur and check the chain length. Really focus on the BCD, as Shimano road has standard and compact chainsets and they can both take 50 tooth chainrings. You probably have a 130 BCD, if you are running the usual 52/39, the 110 BCD compact chainsets are usually 50/34.


Maximise exercise benefits After 10 months my commute has gotten to the stage where it's quite easy and I'm looking for ways to maximise it as a workout and hopefully benefit more muscle groups. Currently it just seems to work my thighs.

I don't have time to ride for fun, but my commute is an hour each way which seems plenty. If I wanted to spend more time I could do a stomach/calf workout instead.

I would have thought it would use the calves but it doesn't seem to (I don't feel any burn in the calves).

Ideally I would like to work my abdominals while riding. Is there any way I can do this? I have thought perhaps purchasing a weight belt so my stomach has something to push against but I'm reluctant to spend the money for something that might be useless and I'd have to wait a month for shipping.

So my question is, is there a way to benefit more body parts than just the thighs while cycling?

Vary your cadence during your commute.High cadence (90 - 110+) will train the heart. Low cadence (60) in a Higher gear will give your Legs Back and Arms a good workout.Dont forget to do some regular stretching esp on those big glutes.


9 speed Shimano shifter with 7 speed drivetrain Can I use a 9 speed shifter with a 7 speed drivetrain, with good shifting and without needing complex adaptations?

I am considering that as an alternative for this need:

Using only the brake lever, separated from an integrated shifter/brake

Suitable Shimano integrated shifter/brake replacement for old STX

Shimano STX rear shifter, broken spring

Assuming that is ok, are there 9 speed shifters integrated with brake levers for cantilever brakes? I have mostly seen 9-speed brifters for disc or V-brakes, but not for cantilever.

PS: There are posts related to 8 speed shifters with a 7 speed drivetrain, but I have not seen anything for 9 speed shifters

8 speed shifter with 7 speed cassette

Can you use a 8 speed Shimano shifter with a 7 speed cassette?

Can I use a 9 speed shifter with a 7 speed drivetrain, with good
  shifting and without needing complex adaptations?

Kinda, maybe, sort of... its complicated

You could use a Shimano 7 speed derailleur with a 9 speed shifter, if you also used a wheel with a 9 speed cog. The 7 and 9 speed Shimano derailleurs use the same derailleur ratio of 1.7 (amount of derailleur movement for a given cable pull) despite the two systems having different cable pulls (2.9 and 2.5 respectively) and sprocket pitches (5.00 and 4.35 respectively).

If you used a 7 speed cassette, with a 9 speed shifter and 7 speed derailleur you would not pull enough cable and the shifts will get mangled.

If you are currently on 7 Speeds, this means you have a 7 speed wheel that will most likely NOT take a 9 speed cassette.  This would mean you would need to buy a new rear wheel as well as a new 9 speed cassette in order to keep you 7 speed rear derailleur.  You would also need a 9 speed chain (which is narrower) to mesh with the 9 speed cassette, which may or may not work okay with your 7 speed chain rings.

For pull ratios see http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/


attaching seatpost acessories to rear of racks? most night lights are designed to attach to the seatpost. but while carrying a bag on the rear rack that area get's blocked.

some manufacturers sell cheap, awful, lights that attach to the rack (topeak) but i figure some kind of adapter would be much more useful (mostly since everyone may have night lights before getting a rack... i do :)

but my searches for such a adapter failed. do you know any?

This is one example of night light i have
http://www.dealextreme.com/p/rechargeable-7-mode-red-5-led-safety-bike-tail-light-with-7-mode-2-red-laser-beam-35mw-90117
(i regret. do not buy, laser is useless snake oil. but the leds are OK. EDIT: regret #2, i had rain for the 1st time --socal-- and when wet, the shorted the buttons which are obviously not water proof, so it spend all night turning the leds and laser randomly on and off. battery hold up ok though.)

and this a rack
http://www.blackburndesign.com/racks/mtn-2-rack.html
(it has a hole on the back, where you can fit a L shaped adapter that holds a reflexive cat's eye)

One possibility is to use extra rubber shims to use the seatpost attaching mechanism to attach to the stay of your rack, like so:

You might be able to use something like the Low down light mount bolted through that hole to give you a little bit of post hanging from the hole and use that with the seatpost mount...

You might be able to mount the hardware without the seatpost mechanism to the hole of an L-bracket mounted in that hole...

With racks with a more serious light mounting bracket instead of just a horizontal hole, I've found many light can clip directly to the bracket with no extra hardware at all, like so:


Differences between bikes 10 years ago and now? I'm not too knowledgeable on high-end racing bikes, but I'm looking at getting a used Specialized Roubaix, and I was wondering whether enough significant advances have been made since 2007 to consider getting a newer lower-end model vs a 2007 S-works Roubaix.

Have there been any advancements that render bikes from that long ago obsolete at the high end?

You did not disclose the used price but that is most likely putting you in a mid range bicycle.

Drive train:
The information I pulled up the drive train is 2 x 10. Seeing more 1 x gearing now but 2 x 10 is in no way obsolete.  You can certainly get 1 x in mid range bicycles.  If 1x gearing is important to you then go with mid range new.  You are going to go from a high group set to a lower end group set.  I would take the older high end group set every time if it is in working order.

Brakes:
The 2007 has rim brakes. In the mid range you now have the option of disc brakes.  Do you want disc brakes?  Rim brakes are not obsolete and have done the job for many years.

Rims / Wheels:
You are definitely going to take step down on wheels. If the wheels are in good shape I would rather have older high end wheels.

Frame:
Frame, headset, bottom bracket are all modern.

Use case:
If you are not going to race you may select a different style of bike but the Roubaix is a nice versatile bike.

Value:
You don't say the price but compare that price to the new bikes at that price. My experience is you can get some really good pricing on high end bikes as high end riders with the money want to trade up and get the latest and greatest.  Sponsored riders get a bike a year for cost or less.  According to Kelly the price in excellent condition is $1100 and that is a much nicer bike than a new $1100 bike in my opinion.  If they want $2000 US I would say no as then you can get into a lot more options new with a frame warranty and I would go 1x with disc and stretch it to $3000.  Wearables on that bike are $400.

Risk:
As with any used bike you risk the frame is damaged and that is not always apparent.  But for the right price it is worth it for the wheels and components alone.


Repairing Shimano front shifter ST-EF41-L My son's bicycle gear shifter SHIMANO ST-EF41-L (front 3 speed) malfunctioned (Both levers became free).
I disassembled it and found 3 very small plastic parts on the bottom side of the shifter were  broken and the spring ring which attaches the 3 plastic parts to the axle were out of place.

Can anybody suggest where to get these small plastic parts?
Thanks

Can anybody suggest where to get these small plastic parts?

Buy a new shifter.  Shimano does not sell replacement shifter parts, so the only way to get parts is to buy another shifter.  And it's a lot easier to replace the old broken shifter with a new one than it is to take apart the new one, remove the needed parts, and reassemble the old shifter with the new parts installed.


Will bending the seat post two inches forward cause any unforeseen structural issues? My current bicycle is a 2013 Specialized Allez C2. I'm thinking of using a conduit bender to bend the angle of the seat post two inches forward. A conduit bender can bend one inch for every 3 inches of pipe. I have 10 inches of seat post above the frame of the bike. Now, although the seat post is the cheapest part of the bike, and it can easily be replaced, does anyone foresee a structural problem with that alteration?

What are you are tying to achieve?  Is the bike too long for you?

Bending a seatpost will weaken it.

You can buy offset seatpost.
Most people use them to move the seat back I cannot see why you could not use it to move the seat forward.
But you are not going to pick up two inches.
Two inches would put you almost straight over the pedals - are you sure that is what you want?

And you can get a shorter stem for the handle bars.


Flat tire after inflating to max pressure Bought a used mountain bike for mom. The bike  wasn't used in quite a while . Mom used it for 3 weeks , tire pressure was  ok but it needed some air. So I pumped air in both the tires to max recommended psi on the tire.

After sometime ,  both the tires were flat. I did not hear any sound of leaking air right after I pumped it. I tried it again, this time  I heard a hissing air leaking sound.

What could have happened ?Not sure if anything in the valve is stuck.
How can I determine what is wrong ?

Thanks in advance.

When in doubt, it's much easier to just completely replace the inner tube. They are consumable (like brake pads) and will only cost you a couple of pounds/dollars.

This can be annoying and tricky at first but after a few tries should only take 5-10 minutes or so.

In my opinion, it's easier and quicker to just buy new tubes the next time you're passing a bike shop and spend 15 minutes replacing them than spending several hours identifying and repairing the old tubes - and having the psychological weight of whether or not your repair was fully successful looming over you whenever you ride.

  What could have happened ?Not sure if anything in the valve is stuck.
  How can I determine what is wrong ?

A number of things. The tyre pressure could have been too high for the weight of the person riding it (you don't always need to inflate a tyre to the max pressure), the inner tube could have naturally weakened with age, the rider may have hit a pothole or thorns/nails without remembering it that pierced the tire and tube.

Ultimately; it doesn't matter. The tube is punctured AND old; get a new one and brush it up as bad luck. I doubt reverse engineering the problem at this stage will help you reduce punctures in the future.