Chamois Supposed to be Tight in Crotch? I recently bought my first pair of padded bibs. I was riding 15+ miles on average, so when i got them they seemed like a plush different experience. Now, a couple months later, they feel a little cramped up and tight in the crotch region. I'm not sure if they shrank, or if I'm just now noticing that they are the wrong size. Bibs aren't supposed to be super tight in the crotch area, right? It's to the point where I'm uncomfortable on the ride, and feel the need to reposition my boys.
I feel kinda lost; i went through the trouble of measuring myself according to the company's specs and thought i did a good job.
Any info helps, thanks.

We're all adults here.
When wearing well-fitting bib shorts, a male should feel "cupped"  The legs of the bib shorts should touch the skin all the way up the thighs, through the "curve at the top of the leg to scrotum"  and around the whole area.
Your old-fella should be pointing forward, slightly cupped by the cloth so it points up towards your belly button.
One way to get a good fit is to pull the shorts on, and wearing nothing more, lie on your back on a bed.  Pull one knee up to your chin and leave the other leg more horizontal.  This will help get the cloth up to the aforementioned curve.  Swap legs and repeat.  You should be able to do this without cloth sliding past your skin, and without any large air pockets/spaces being formed beside the legs/scrotum.
One  possibility is the cuffs of your bibs may be too low down your leg/thighs.  You should pull the legs upward to free material for the crotch area.
Also, if you stop for a toilet break, this will disrupt the lay.  So do your best to reestablish the cloth up to the curved area.
The padding should be inside the shorts, not on the outside where its visible to the world.
Chamois cream can be helpful too, but I only wear it for long rides of over 100 km.  This also goes on the skin, or sometimes on the padding.
Lastly, nothing else goes between padding and skin, so no underwear.  The bottom of your T shirt or baselayer is fine to be in the area, but shouldn't be long enough to get that low into your bibs.

There's got to be a better name for "that curved bit between inner thigh and nutsack"


57-584 tire and (50,60,62)-584 tube I have a tube (fits 27.5", 28" and 29"), and a 27,5" tire with the dimensions
57-584 (27.5/2.25, 650B). But the package of the tube only shows suitability for the dimensions (27.5"):

50-584  27.5 x 2.00  650B
60-584  27.5 x 2.35  650B
62-584  27.5 x 2.40  650B

Can I use the tube for my tire? What would be possible consequences?

The tube and tire are from Schwalbe SV-19

'584', '27.5' and '650B' are all the same thing, specified in different wheel size systems.

These size wheels originated in the older French wheel size system and are called 650B (650mm being the diameter of wheel and tire). ETRTO (European Tire and Rim Technical Organization) specifies wheel rim diameters in millimeters (584mm in this case). Mountain bikers call these 27.5" (the approximate diameter of the wheel and a fat MTB tire).

The tire width specifications of your tire and the tube are given in both millimeters and inches. Tube min tire width is 50mm / 2.00", max is 62mm / 2.40"

Your tire width is 57mm / 2.25" so the tube will work with it just fine.


Shimano SLX Rear Derailleur with Microshift bar end Shifters I need to replace my rear Shimano Deore derailleur since it got mangled up in an accident. I'm thinking of replacing it with a Shimano America RD-M662 SLX 9-Speed Derailleur. The bike I have is a 2013 Salsa Fargo 3. It already has a set of 9 speed Microshift bar end shifters. Will this setup work? The Microshift worked fine with the Deore, but will it work with the SLX? Does the SLX require a different cable pull than the Deore? Any help would be greatly appreciated!

Yes, this will work. Just get any Shimano mountain rear derailleur... SLX, deore, LX, xt, xtr, etc...

EDIT:

This only applies for 9 speed and lower. Here's a quote from Sheldon Brown.

  Within a given brand/style of rear derailer, all "speed numbers" are generally interchangeable. This applies to all indexable models, basically everything manufactured since the late 1980s. There are a few exceptions:

http://sheldonbrown.com/speeds.html

The exception for Shimano

  Shimano "Dyna-Sys" 10-speed shifters and derailers use a longer cable pull than other Shimano models, and must be used together.


Can I saw off broken freehub I have a very old bike (circa 1996) with broken Shimano Altus 7 speed, hyperglide-c freehub. The freehub is freely rotating in both directions.
I had removed the cassette, but it seems that there is no way the freehub could be removed with allen wrench: there is nothing on the drive side and it seems like torx slots on the other.
Does it make sense to rebuild the free hub without removing from the wheel?
Does it make sense to take metal saw to cut part of the thing first and then unscrew the rest?
Update: I am considering this tool to disassemble and fix the freehub without removing it from the wheel.
Another update:
The view from the drive side
The view from the other side, the hole diameter is 12mm, it seems like there are some slots there but I am now sure whether I need 10 mm wrench or something else.

I do not believe there are any from that era that don't take a 10mm wrench through the drive side.
The simple thing to do is remvoe the freehub with the 10, gently pry up the rubber seal on the back, note its direction, and shoot air/solvent/lube/oil/etc through it depending on what you've got and how bad it is, then finish with a heavier oil like Phil.
Edit: It indeed takes a 10mm allen.


Advantages of higher quality cranksets What are the advantages of upgrading the crankset on a bicycle?

For example, my bike (2009 Kona Dew) comes with a FSA Dyna Drive crankset. I'm assuming this is a pretty basic crankset since it lies at the bottom of their product list.

Would there be a substantial improvement by upgrading to something nicer? My (uneducated) guesses are that a higher end crankset would be lighter (e.g made from carbon) and possibly have less flex under power application.

They will definitely be lighter, and probably shift a little better. More rigid is possible but not especially likely, as the cheap one will be strong enough to take a lot of abuse (they don't particularly care about weight so that's easy to do).

(edit) A cheap crankset very likely has the chainrings rivetted on, and they're not designed to be changed. Sometimes the smallest chainring is bolted on and can be changed. Swapping one of these for a more expensive one that has interchangeable chainrings will probably give better shifting.

Cheap bikes are the ones more likely to be bought by people who either weigh a lot or are careless with their bikes, so are more likely to be overloaded. More expensive bikes get crashed instead. The cranks are designed accordingly.

As discussed in  Suggestions for progressive upgradation of bike you're almost certainly better off saving up for a more expensive bike rather than trying to upgrade the one you have. Buying parts retail is a lot more expensive than getting them as part of a bike (manufacturers buy 1000's at a time and don't pay for retail packaging).


getting the crank arms off an old bsa bike So I'm resuming work on restoring a bsa bike for my sister.

The first thing I need to do is strip it as it's in need a of new paint job.

I'm having trouble removing the crank arms.

They appear to be bolted on using a round headed bolt then a nut on the other side.

Is there something am doing wrong because the bolt doesn't appear to come out. Even when I whacked it multiple times with my hammer it still didn't budge.

Use a length of conduit or other metal pipe or some other kind of brace to transmit load from the crank to the ground, so that the hammer impacts are not going right into the bearings. Then hammer it with everything you've got. Try to go for fewer strikes and more power. It's a press fit you're overcoming; it's supposed to be stuck.

Always plan on having to replace the cotters. They don't necessarily get too mangled or bent to re-use but they often do. Replacements are still pretty available, although there are multiple diameters (I think 4). You re-establish the press fit with a hammer or press, never via the nut - it can shear the cotter if you try. Sometimes you have to file new cotters to make the angle right (make the cranks 180 degrees apart) if you only replace one of them. The other very important thing is to re-tighten the nut on a freshly installed cotter after a break in period at first, say 50 miles.

Despite being a pain, they do work and all you really need to work on them is a hammer and piece of pipe.


How to treat rust spots on a steel frame without stripping the paint completely? I have a 1974 steel French road frame and most of the original paint is still intact. However, there’re quite many 1-2 cm surface rust spots. I also recently had one of the lugs partly re-brazed and the guy who did it removed most of the paint around the lug. How can I treat the rust spots and that area where the paint was removed without repainting the whole frame? What solutions can I cover only those specific spots with after removing the rust from them to prevent rusting (if possible, without using paint – I kind of like the look of frames with places where bare frame is seen)?

I would lightly rub the offending area with steel wool. The idea is to not completely remove the rust but to dislodge any paint that is intact but not bonded to the metal. Apply a rust restorer or converter. Rustoleum is one brand but there are many others. Apply the converter to the prepped areas per the instructions. The chemical process converts the rust and leaves a coating on the bare steel(typically black). You can then cover the areas with either touch up paint or nail polish of a similar color. If you visit a Hobby Shop they have small bottles of enamel paint that you could custom blend to get a close match.


Rear Derailleur Cage Plate Catching Chain at Lower Pulley Just got a new Felt (Z85, 2015). Was adding oil and cycling through the gears of the rear derailleur when the chain got caught on the lowest gear.

It appears that the cage plate is catching at the lower pulley. See the attached pictures.

Is this a straightforward fix or should I take it to the store.

Thanks!

Basically your chain is too short / largest gears are too large. You should probably take it back to get a longer chain or smaller cassette, especially if it is still on waranty.


Will I damage my brakes if I remove the dual brakes? I bought a vintage schwinn that has dual brakes. If I remove the dual brakes (I think they're also called safety brakes), will it ruin my brakes?

You will not ruin the brake levers by removing the sissy bar.  However you will need to adjust out the extra slack in the inner cable.

What you will do is take the bike further away from originality.  For better or worse, that's what the bikes had back then.   So if you ever imagine anyone might want to restore it, please keep all the parts aside.


How to reduce brake lever rattling sound at the pivot pin either by a fix or by replacement? Context
I have a Merida Speeder 200 with a Shimano MT-200 hydraulic brake system, which uses BL-MT200 levers.
Over time these levers have developed a rattling sound. It appears to come from the lever rattling against its housing at the pivot point. Intuitively I would tighten the pivot bolt, but it appears to be a rivet, so I can't really do anything with it.
Things I've looked into
The answer to this related question mentions using an o-ring, but because of the rivet-like pivot I can't disassemble the lever.
The sound can be damped easily by just resting my fingers on the levers, but I sometimes prefer to just hold the bar without my fingers on the lever.
Question
Can I silence these rattling levers? Or is there perhaps a compatible lever that does not rattle?

The lever of this specific model is not replaceable. So you can try your luck with a thick grease, or by "inserting" some layer of foam, or gluing little patches of old tubes in between the lever and the housing, close to the rivet.
The rattling is happening because of some play between the parts. The weight of your finger is enough to keep the parts in contact ---> replicate that by putting some material in between.


How should exactly the brake cable be fixed to V-brake caliper? Regarding the V-brake calipers, where the cable is tightened with a screw:
Should the cable go between the head of the screw and the washer (1), or should it go between the screw head and the body of the brake caliper (2)? And most importantly, why? (Is either of the two dangerous, e.g. could the cable slip or break?)
(1) Cable between the head of the screw and the washer:

(2) Cable between the head of the screw and the body of the brake:

Picture 2 is correct. The washer should prevent the cable being damaged or pulled by tightening the bolt.
However, on some cheaper brakes the bolt and washer are such poor quality that they turn together and the benefit is lost.
I will add that your cable in picture 2 isn't seated deeply enough behind the washer.

Note that i usually leave more cable and tuck it away behind the spring. This photo is OK for reference to clamping though.


Suitability of Giant Aero RS2 for occaisonal on-road mountain trips I'm planning to buy a bike for use only in summer, mostly on 100% flat terrain (being The Netherlands). However, I would also like to be able to use it as a packing mule and go into the mountains for a week, on-road, once a year.

If you take Giant, they have the Expedition LT for the latter. But, it does come with a hefty price tag (€ 1900). Giant also has the Aero RS1 (€ 1300) and RS2 (€ 900). The RS1 having a completely different frame, being lighter (which is not relevant for me, since 1 kg on 30 kg of bags won't make a difference).

I know that the Expedition has better Shimano sets, hydraulic disc breaks (although I have my doubts about disc breaks; spoke shearing forces, complexity), etc, but I was just wondering how a bike like the Aero RS2 holds up when going into the mountains, on-road, once a year for a week. It does have mounting holes for front bag carriers, so at least in that sense, it's prepared for it,  but they do call it a 'lite trekking' bike. I just wonder if that means something, or if that is only to give credence to the existence of higher priced ones.

The only thing I may actually miss, is the hydraulic breaks, for their better control. Giant has other bikes too that have hydraulic breaks, like the Futuro RS1, but its front fork has no mounting holes for bag carriers, and it has suspension (which I don't like climbing).

If you're going on road, a hybrid should be fine (like the Aero RS2) - the gearing and tire size and handling should be reasonable provided you don't go too high on the weight. I'd probably not load it too much though (for that you want something intended for touring). At 30 kg of stuff though, I think I'd look for something more touring bike-y than the Aero RS2 - its part of Giant's casual series and carrying 30 kg of stuff isn't really in the casual realm and you could likely do better for 900 euros in that realm.

A more reasonable option overall would be to buy a bike that works well outside the week of mountain touring, and rent a bike for the week long mountain trip.


How can I tell if my presta valves have removable cores? I read about valves that have removable cores and that is better for applying sealant. How can I tell if my valves have cores that are removable?  (I don't have the type of the tube, or any other info; used bike).

Have a close look.

On a presta valve there is a wide threaded part that the lock ring attaches to. And a narrower part with the valve lock nut above it that the cap threads onto.

If the narrow part has two flat sides to get a tool onto, then it's removable.


how to pump up schrader valve bike? I'm quite new to bikes.
I have a Schrader valve bike with deflated wheels. When I try to pump it up. I take off the protective cap, then there is a valve secured down by a nut (there is another nut securing it to the actual wheel) I then put the pump onto the bit of valve poking up and lock it in. I can then pump it completely with about 5 pushes of the pump. Once it is complete I unlock the bike pump off of the valve, at that moment all the air rushes out immediately (10 seconds) even if I put the protective cap on. What does this mean??

From these three, which one you have?

Case ①:

Schrader valve

Check if the inner part (valve) is properly installed (tight enough). If is and still loose air — you need to change the valve or the inner tube, the problem is with one of them.

Case ②:

Presta valve

You need to unlock the valve before pumping, or you will pump air only into you pumps' hose. After pumping don't forget to lock the valve back.

Case ③:

Woods (Dunlop) valve

Very old system. Check inner parts (steel needle and rubber tube) for damages, rubber tube can degrade flexibility with years → air loss.


Shimano Deore Squeaking Sound Any suggestions on how to reduce/eliminate the squeaking sound on my Shimano V-brakes? I dont remember doing anything, i just wipe my bike and rims every after ride.

Check if there is any mud in brake pads.
Try cleaning the rims with alcohol :)
Read this http://www.bikeforums.net/mountain-biking/45251-cleaning-rims-alcohol-benzine-solvent.html


How many headset spacers might I need? I am building a bike. The headset is in the head tube, and the next thing is to fit the stem and handlebar to the steerer. At this point, it seems I need some headset spacers in between the headset and the stem.

How many headset spacers am I likely to need? Or rather, how much total height of spacers? Is there any way to work this out other than trial and error?

The frame has quite different geometry to my current frame, although my body's geometry is not changing. Should I try to reproduce the space on my current bike?

Headset spacers are available in all sorts of combinations; would it be prudent to get something like a pack of five 10 mm spacers? Or a set of a 10 mm and two 5 mm? Am I likely to need more space than that? Less?

You can get a close approximation if you have access to a trainer. Install the bike in the trainer with the fork and headset installed. Using a front wheel riser block will make the fit closer to your actual riding position. You can now install the stem at any height you like. When you find something close measure the gap between the bottom of the stem and the top of the headset. I would get a variety set. Most come with a 2mm,5mm,10mm and 20mm. I just did this myself and I got an extra 20mm that I installed above the stem.This allows for some flexibility later. The spacers can be shifted for a different fit for different riders or resale. It is easier to cut the steerer later than try to make it longer.


rebuild shimano wheel I've dented the rim on my Shimano WH-RS-10 rear wheel. I found the tech doc pdf. I've had wheels rebuilt before but always with rims that were available to consumers. I can't find any place that sells the Shimano rim, nipples, or spokes to rebuild this wheel. I know I can get close matches from other companies, but I'm looking for identical components to match the good front wheel I have. Does Shimano actually provide these components for sale? Would this be something my LBS could order?

Yes, you can order replacement parts from an LBS who is, or has access to a Shimano distributor.

You are unlikely to find that rim or those spokes in stock, because they are unique to the wheel, and it is not cost effective for a shop to keep them on hand given the relatively small chance that someone will need them.

Ordering them, though, should be straightforward, and cost less than 200 dollars.


How to upgrade a dust cap? For all you mechanics out there I am sure you hate these things. Dust caps are the bane of my existence. They are cheap and bend easily. I want to get a better sturdier one for a bike I am working on. What do I want to look for? Is it just the sizing of the crank that matters or are there other factors?

Assuming you mean the bottom bracket bolt cover (per wikipedia) there are two horrid types, and no good ones I'm aware of.

The expensive ones are metal and exactly match the thread of the crank so they shield it and keep it clean. They're also fragile and easy to damage as they're not strong enough to take much force but they have a large thread contact area so become quite solidly stuck over time. They're also expensive (did I say that already?).

The cheap plastic ones don't look as nice, but are lighter and easy to replace. They're also easy to damage when removing them and often the little plastic tabs break off even if you're very careful. The flip side is that you can buy a packet of 10 for about $5. But not online, by the look of it. eBay has single caps at about $1 each, which is IMO unreasonable, and no-one's selling larger quantities. I think you'll have to pay whatever your LBS charges, unfortunately, or buy a box of 1000 from China. Classic small part problem - you're paying $1 for the LBS to handle the product which is most of the cost.


My LBS does not carry fixed-gear/single-speed parts. What next? Question Changed. See Below for Original.
My local bike shop neither carries fixed-gear/single-speed parts nor is very knowledgable about the topic.
Should I find an online storefront to take its place? Or try to work with my LBS to get the parts I need?
Original Question: Online Shop Suggestions for Fixies/Single-Speeds

I'm looking for a reliable online shop for fixed-gear/single-speed parts. I have a frame and fork and am wanting to buy new, quality parts to complete my first build. Any suggestions?
Looking for (EDIT):

Fixed/Free wheel-set, cogs and crank.
Shop specializing in, but not limited to, fixed-gear/single-speed parts.
Quality customer service by email or phone.
A local bike shop with a good online storefront.
Prompt shipping.
Ships to U.S. (Texas)

I've tried my local bike shop for these parts, but unfortunately they were not very helpful after mentioning single-speed (they were cool about it, just uninformed).

Your local bike shop may not get it with fixed/single speed but do not discount them entirely. They can sometimes compete on price better than a mail order company simply because they will not be charging you shipping even if they have to get parts in specially for you.

Most bike shops have at least a couple of regular suppliers and these suppliers will almost certainly have what you need. Also, there is always the option to get spare parts for a particular bike. If you like the wheel set that comes with a a e.g. Specialized Langster and the shop do Specialized then you can ask them to quote you for a replacement wheelset. The same goes with Kona/Giant or whatever it is they do stock. With some brands these replacement parts are surprisingly competitively priced. Give the local shop a go even if they do need extra prodding and, if they are any good, they will give you service that the online box-shifters never can.


Custom Shimano 3x11 drivetrain I have a Trek 720 disc which came with a 2x11 Shimano 105 drive train setup.

When it's fully loaded for touring going up steep hills is just too hard - I'm barely heavy enough to push the pedal down.

My idea is to put a triple on the front.
I've found all these Shimano 105 triple components available so hopefully compatibility should not be an issue:

Triple 10 speed 5703 Chainset
5703/5700 Left shifter
10 speed 5703 Front derailleur

My concern is that the chainset and derailleur specifically state 10 speed - and I want to use them with an 11 speed cassette. I also plan to tour in some potentially quite remote areas so reliability is a priority for me.

Do you think this setup will work ok?

No you would either have to use a 2x11 speed drivetrain or a 3x10 speed drive train. You can't pick and choose and any hacks would reduce reliability.

Using the 10 speed 30/28 is the same gearing as 34/32 on the 11 speed so no advantage on the change.

For remote touring maintenance is as important or more important than gear selection.

For long distance touring 10 speed would likely be more available on the road as 9 speed is being gradually phased out and 11 speed still quite new so would factor in what stock bike shops held.


replacing lower jockey wheel my lower jockey wheel is a plastic affair 12tooth that has no bearings just a bushing. It gives a lot of friction and a lot of side to side movement. I wish to replace it with perhaps a metal one with sealed bearings but I can only find 11tooth and 13 tooth, would either of these work and which one??

Jockey wheels with bushings are pretty common. (NB for readers not familiar: bushings, aka plain bearings, just have the axle rotate within a plastic or bronze sleeve rather than supported by bearings. The bushing materials are self-lubricating.) Also, the plastic in question is a pretty common material for jockey wheels, and it is not intrinsically fragile in that application. That was discussed on a previous Stack Exchange post. Furthermore, the jockey wheel may appear to have relatively high friction when spun by finger, but we don't push the pedals with our fingers. The amount of friction is pretty marginal in the context of your total power output. That said, play in the lower jockey wheel is probably a sign that it's wearing out. Note that play in the upper wheel is by design.
On performance road bikes, one of the minor new trends is to replace the jockey wheels with slightly larger ones, e.g. Kogel Bearings makes 12t upper and 14t lower pulleys for current generation Shimano road groups, which come stock with 11t pulleys. However, the clearance between the upper pulley and the smallest cog is a potential issue, and some Shimano groups can only take 11t replacement upper pulleys. On the lower pulley side, there may be interference between the pulley teeth and the cage.
Thus, extrapolating to your group, if you are dead set on metal jockey wheels, it would be safest to get the 11t pulley. A larger jockey wheel may work, but it's not guaranteed. At minimum, you'd need to provide your derailleur make and model. As described in the first paragraph, I'm not convinced it's necessary for most riders to upgrade to metal pulleys and cartridge bearings. In interest of full disclosure, I did upgrade the jockey wheels on my road and gravel bike to 12/14t Kogel units, which are aluminum with ceramic bearings. That was for performance reasons, but the expected difference in drivetrain friction is small, maybe 0.5-1W at 250W input power. I have typically seen long life out of the stock plastic pulley wheels.


Can anyone tell me if this men or womens bike and possibly model? This bike is dirt cheap and fits my needs. I don't want to ask the seller too many questions and then discover the bike is worth more and not sell it. Im picking it up tomorrow for a steal. Question is this a girl bike and possibly does anyone know model outside scwhinn sierra? I cant find a similar picture of any bike so i cant I.D. any help would be appreciated.

I see "Schwinn Sierra" in the decals your photo.  I'd guess its somewhere between 2000 and 2010 in age.

As long as it works, stops safely, isn't going to fail, then its a good bike to ride.

Yes, it would be classed as a woman's frame, but there's no physical reason a male couldn't ride it as well.   It may have a female-specific saddle or might be slightly angled up at the front, but that's easy to change.

There's suspension, but its in the seatpost, and possibly some in the handlebar stem (or its an adjustable stem)   The saddle is also sprung.

The black bar is a carrying adaptor for a car rack, replicating the higher top-tube of a men's bike.  Its not part of the bike and probably shouldn't be there for riding because its clamped to part of the handlebars that should turn freely.

Schwinn marketted very similar bikes under the models "Quest" and "Mirada" (that mirada is older than the one in your question)

The picture is not great so can't really comment on the bike's condition.

A $10 bike that does its job is totally worth it.  By the looks, you get lights too, which would cost that by themselves.


How to narrow down choices when finding a new bike? I am about to buy a new bike. Not a second hand one; a brand new. I am looking at specifications and webshop prices to get an idea about what should and could buy, but the spectrum is too wide to check every single one in a shop. I noticed, that most brands have models with different components, and the maxed-out version is 3-4 times more expensive than the cheapest one. There are minimal differences in function, but not on the price tag. Like this cross bike: Kross Evado 1.0-7.0. Local brands tend to be cheaper, but they do not have high-end machines on their palette, so I am a little bit concerned about the quality.

Most LBS here sell 2-3 brands only, so it's really hard to do a side-by-side comparison in real life, and I am not too familiar with component levels.

What is a good heuristic to find the best value for my money? What to look for when comparing two bikes by their specification only?

(To be more specific: I am currently looking at hardtail MTB's and cross (hybrid?) bikes, mostly from the lower end. I think I know my preferences fairly well, but I've never had a bike with discs or suspension and do not know what to look for.)

As someone who has recently done the same thing, I'll think I can help with this.
The biggest trap I fell into was overthinking it.

Some of this might sound a little backwards but it's my thinking at least.
As a starting point, you need to work out your budget.  No point considering anything that's outside that.
Sounds like you already have your intended use sorted, but that's a pretty big thing to nail down
Next thing I would suggest is pick an pick a bike shop that seems to know what they are talking about and not just flood you with marketing jargon.  Find out what sort of follow up service etc they have.  As a starter, you're probably going to need some help with setup & maintaining the bike so pick one who will.
After that, take a couple of options from that store in your budget for a ride, see what you like.
Then buy the bike.


Rear derailleur and front shifter are not indexing "together"? So my rear derailleur and front shifter have stopped working together, my shift can shift once up and then nothing. My bike has essentially turned itself into a 2 speed.

The shifter is a 2300 shifter and the derailleur is a 105, both compatible with each other and my 8sp cassette (I know this because it has been working fine for a year).

So the other night I moved my cable because it was kinda blocking my light and then all of a sudden my derailleur and my shifter had disengaged and I was stuck in 1st gear.

I thought possibly the cable had slipped from the rear derailleur and that was the issue so I tried adjusting it with no improvement (in fact I made it slightly worse because I am now stuck in my highest gear).

My question I suppose is, how do I figure out if it is the derailleur or the shifter and does anyone have any idea how to fix it? The shifters seem like black magic since I can't really see what they do and all the mechanisms and screws are hidden away. I may need to replace the cable as I have kinda messed it up and got it all frayed and prickly (lost the nipple), how difficult a job is that?

Cheers

If you need to replace the cable, try this:

Shimano 105 Shifter Cable Removal

Take the bike for a short ride and shift into the gear that gives the shifter cable maximum slack. For the front gear shifter, maximum cable slack corresponds with the lowest gear. For the rear gear shifter, maximum cable slack equals the largest gear.
Loosen the bolt on the derailleur that secures the shifter cable with a 5-mm hex wrench. The shifter cable is attached at one end to the Shimano 105 shifter and at the other end to the derailleur.
Cut the metal cap, called the "ferrule," away from the end of the cable, using cable cutters. Grab the cable where it enters the derailleur and pull it free.
Squeeze the shift lever on the Shimano 105 gear shifter to expose the head of the cable. The cable head is located on the side of the top of the shift lever.
Grab a portion of the cable and push it forward, forcing the head of the cable out of the Shimano 105 gear shifter. Grab the head of the cable and pull the cable free.

Shimano 105 Shifter Cable Installation

Thread the replacement shifter cable through the hole in the Shimano
105 gear shifter. This is the same hole from which the old cable
emerged. The cable has two ends, with a metal fitting at one end,
which is designed to anchor the cable inside the shifter.
Pull the shifter cable taught until the metal fitting is fully
anchored.
Pass the cable along the bicycle. The cable follows the exact route
of the old shifter cable, passing through the cable housing and
cable stops before arriving at the derailleur.
Thread the shifter cable beneath the derailleur bolt and pull the
cable tight.
Tighten the derailleur bolt onto the cable, using the 5-mm hex
wrench. The cable will be excessively long and will need to be cut.
Cut the cable just past the derailleur bolt, using the cable
cutters. Leave enough cable, approximately 2 to 3 inches, to allow
for future adjustments of the cable.
Press a new ferrule onto the tip of the cable. Squeeze the ferrule
onto the cable using pliers.

from: http://www.ehow.com/how_7706040_replace-shifter-cable-shimano-105.html


What do you do if you find your stolen bike's frame on ebay? I am 85% certain that I see my bike's frame on eBay. It costs almost 2k with all the components and I see the frame on sale for $400 with seat-post and fork only. All my stickers not in the pictures(3) however the frame is the same size and picture only shows the side with no identifiable mark.

The frame itself is rare, not expensive but the brand is not widely sold. And if its sold used, its almost always a complete bike. The manufacturer doesn't sell frame only.

It was stolen, from a bike rack, in open daylight in downtown in big city, I suspect that I forgot to lock it. Lock was on the frame and so was my helmet. I reported the bike stolen on bike index and did file a police report. And posted the bike on local FB groups for stolen bikes.

It is now on sale on ebay, 5 days after about 100 miles away from where I am. Item says local pickup only?

UPDATE: I am now less certain that it is indeed my bike. More like 40%

To determine if the bike is indeed yours, you could contact the seller and ask for more information about the bike and for more pictures in the hope that you'll get one with a visible identifying mark.

You'll need to be careful. If the seller know's it's stolen asking for more information and pictures could tip them off that you are the rightful owner with the intention of retrieving your property.

You should read the Ebay Stolen Property Policy for what to do if you are convinced the bike is in fact yours.


Touring bicycle must-have features What should I take in consideration as an important feature(s) for a touring bicycle?

My goal is to use it for long distance trips and eventually work commuting.

I'd go for a longer bike rather than a short one.  This helps handling at speed and makes it easier to hold a line.   A shorter bike needs steering input all the time, whereas a longer / more relaxed geometry will track by itself, but will need more effort to turn.

A packbike is no use if you can't carry the things you need.  For some that might be as little as a water bottle and a credit card.  Other riders might want to pack along a kitchen sink and every possible convenience.  How you fit it all on the bike is a separate question, but rackmounting lugs in the frame will be easier than trying to fudge things.

You should look at handlebar positions too - long distance riders like to have many hand positions, so at least have barends on a flat bar, or have drops, or have trekking/butterfly bars.

Saddle comfort is important too - whatever works for you.

Mudguards/fenders, because not every day is good weather.

Lights, both DRLs for safety in the day and full-on lights for night riding.  At least two front and two rear.  If you can go one from a dynamo that will give battery-free riding.

Reflectors - they only work when a light is shining at you, but they're small and light and completely autonomous.  I use DOT tape and stick portions to parts of frame.  I also have clip-on wheel spoke reflectors to replace the yellow plastic block ones.  They're excellent.

Consider that your work commuter might be a different bike - the risk there is theft.  So a nice touring bike will vanish pretty quick if locked up outside.


Can hand brake levers be pulled hard enough on a comfort/cruiser handlebar? My bike currently has a straight handlebar. Both the front and rear brake are operated by hand, with a brake lever on each side of the handlebar. This allows me to pull them very hard, which is good.

I consider changing the handlebar to a comfort/cruiser handlebar. But I worry that because the ends are tilted backwards (towards me), this makes it more difficult to pull the brake levers hard enough. Is this the case in practise?

Comfort/cruiser bikes usually operate the rear brake by foot, hence they don't have this problem to the same extent.

You will have no problem with the brake levers. The force you apply to the levers is between your fingers on the lever and the palm of your hand on the bar grip, so the angle of your hand with respect to you body does not matter very much.

If you want to convince yourself, sit on your bike, turn the handlebars slightly so the bar is at an angle less than 90° to the axis of the bike and squeeze the brake lever.


is it worth to change slx 2011 rear derailleur for xtr 2009? I bought a bicycle last summer a Specialized camber comp and it mounts Shimano SLX as rear derailleur. My intention is to change it for a xtr derailleur (from 2009) which is mounted in a bicycle I barely use, the derailleur is as new.

do you think is worth to swap them? I am also planing to change the alivio shifters for a better ones since I think the whole set won't be balanced.

In my experience, the differences should be so small that I wouldn't botter the trouble just for the sake of change.

But, if you have a GOOD REASON (noticeable performance or weight difference for intended use), then XTR, even 2009, should be better than a brand new XT, although I think both are very nice - to the point you cannot tell the difference if you couldn't look at them or know which is which while riding.

In the end, personal taste and preference would determine the best option, I think.


Vulcanizing cement question? I was sent vulcanizing cement instead of rubber glue. I need a strong glue for LED strip lights. Everywhere I go looking for vulcanizing cement answers leads to tires, but not what all else it can be used for. Can I use vulcanizing cement on LED strip lights?

Vulcanization is used to describe the chemical process of hardening rubber. Essentially, Vulcanizing rubber cement is the same thing as rubber glue, but contains accelerators to speed up the drying process, which is why it's handy for patching tires, since you want a fast drying adhesive for patches.

There shouldn't be any issue using it to adhere LED strip lights, just avoid covering the LEDs themselves with the cement as it'll cause them to heat up, and heat is what kills LEDs. Also avoid covering the solder patches with cement if you plan on using them down the line. Otherwise, the product is fairly inert and won't damage your LEDs.


Yes/no replace chainrings+cassette after chain failure? I had a pretty bad chain failure a couple of days ago. I bought the bike second hand about a year ago, and in all fairness I had not done much maintenance on it since. I discussed with a friend and after showing some images, he recommended to change the cassette and chainrings too. This is a nontrivial expense for me and he did not seem to be aware that the teeth on these rings are not supposed to be all exactly the same (so the recommendation might have been based on that judgment).

I have thoroughly cleaned the cassette and chainrings, but find it hard to decide if they need replacement. After some research I figured that these parts should often be replaced even before they show visual tear, so I am choosing between trying only a new chain first, or not even bothering trying the old cassette+chainrings and getting new ones straight away.

Should these parts be replaced, based on the attached images? Or should I try a new chain only first, then decide on the ride experience?

I'm pretty new to cycling (maintenance), so any advice is welcome.

Images of the chainrings:

https://drive.google.com/file/d/171Y8GkHIazoUpsi193cJDTCLCSA303Gc/view?usp=sharing
https://drive.google.com/file/d/1bEjFhXYGA7bZACvhgLaKIaeVaGxng8G9/view?usp=sharing

Images of the cassette:

https://drive.google.com/file/d/1LyLW_y22JIImM1SidEyc9fi3ChCFKJco/view?usp=sharing
https://drive.google.com/file/d/1GmMbabw11xpt9RADFe1GUCbcjix8FlpD/view?usp=sharing

Image of the failed chain:

Yes. The cassette teeth are clearly worn, and the large chainring teeth have worn into characteristic shark fin shape. If you use new chain with these, it will skip. The small chainring looks still good.


How do different frame materials affect the handling of a bike? I can appreciate that some materials are lighter than others and some have more flex than others, but overall, how do different frame materials affect handling of the bike?

Assuming the same geometry and design. What are the main handling characteristics of each of the below common frame materials?

Aluminium alloy
Carbon Fibre
Steel
Titanium

There is a plethora of alloy and carbon bikes which contradict a lot of the above.
Certainly with early alloy framed bikes a lot of what has been written above was true - fat tubes, straight gauge, non-profiled. This is where alloy got its harsh ride reputation from. And cheap alloy frames probably still bear this unfortunate hallmark and reputation.

If you look at the other end of the spectrum with the likes of Canyon's Ultimate SLX AL or Cannondale's CAAD12 - you will see careful design can produce a frame which is both compliant and light. The Canyon frame weighs in from 1kg - lighter than a lot of carbon frames. It has a stiff bottom bracket and the over-sized head tube ensures handling is tight. The stays are pencil thin for compliance - and I can confirm it rides great. I would have no hesitation riding it on distance rides.

On the other hand - if you look at a Cervelo S5 aero bike - that has one of the firmest rides I have ever experienced. Harsher than an old Scott Foil. And these bikes are carbon. Supposedly "Soft, You can feel the Flexing".

Then you look at the Genesis Volare in Reynolds 953 steel. You'd instantly think sublime ride - but the frame had to be revised because it was too harsh. And this coming from feedback from the race team.

My point being - material choice alone - does not dictate handling of a bike.


How can I make myself and bike more visible during the day? How can I make myself more visible during the day?

Maybe something to put on my helmet (so it's easy to remember).

1.  Wear hi-visibility color on your torso.

That really bright yellow/green color is best. The orange is pretty good, too.

I've seen stuff that's striped in both colors or is primarily one with a some bands of the other, and that seems like probably the best option, so that you still stand out against a background that matches the hi-viz color.

Helmet and leg stuff wouldn't hurt, but will tend to be less effective than torso, since the helmet is fairly small and your legs are fairly low.

There's a lot of available options for getting hi-viz colors on your torso. Most include reflective bits. Things like: a safety vest, a hi-viz safety triangle belt, a hi-viz cycling vest, a hi-viz cycling jacket, a hi-viz cycling jersey, a hi-viz t-shirt, or even just a regular t-shirt in a bright visible color... Most bike-shops will have a hi-viz jersey and hi-viz cycling vest or cycling jacket available. "Work wear" shops that sell uniforms and other work-clothes will often stock a variety of high-visibility stuff.

2. Attach hi-visibility colors to the bike.

A safety triangle hanging from the back of the saddle. A bag under your saddle in a hi-viz color. Hi-viz colored panniers. Hi-viz colored reflective tape on your fenders or other parts of the bike.

This will be lower and smaller than on your torso, but couldn't hurt.

3. Bright flashing lights

You need unusually bright lights for them to have a chance of being at all useful in full daylight.

I have the Cygolite HotShot that won the Tail light review on our blog. It's definitely visible in daylight when it's in a flashing mode. My 300 lumen headlight in flashing mode is also visible in daylight.

4. Ride visibly and predictably

Ride where you'll be seen. Ride where cars will be looking for you. Don't ride in the gutter or hug the curb. Merge into the lane position a car would use to go straight when approaching a place that a car can turn across your path. Claim the lane when appropriate. Take a safe cycling course, or at least read up about Vehicular Cycling.

This is probably actually the best thing to do.

5. Ride with other bicyclists.

Hard not to see a pack of 20 cyclists riding close together.


What kind of flat is this? I'm stumped. For the last yew years I have been getting flats that look like this:

As you can see, it's a tiny, tiny hole that can only be found by inflating the tire to twice its size or so. I know these aren't puncture flats because there is never anything in the tire, and they don't seem like pinch flats because:

They never come in pairs
They happen much more frequently on my front tire even though my rear wheel has much more weight from loaded 40L Ortlieb paniers.
I'm running between 110 - 125 PSI, and more pressure doesn't seem to reduce the rate of flats.
They tend to show up when I go to get on my bike in the morning, rather than on the way or after work. (Though this doesn't really contraindicate a pinch flat, I just thought it was weird).
They seem to mainly be on the outside, although sometimes they are on the inside of the tube.

Lately they've been happening more frequently, today I had three (I found my bike flat in the morning, then tried two more patched tubes with similar flats that I had missed).

There are the usual gotcha's that I usually try to avoid too:

Watch out for lips/edges on the road.
Only use tire lever for tire removal, not replacement.
Put some air in the tube before putting on the wheel to avoid folds/bends
Make sure rim tape is fully covering all spoke holes

I'm getting tired (pun not intended) of these, so before I buy a new (bigger) wheelset, I thought I'd call for help.

Thanks!

Some more details: Mavic CXP 30 700c wheels with Continental Gatorskin 700x23c tires, 4 mile commute each way over decent roads in hot conditions.

That looks like the sort of hole you get from tiny bits of glass working their way through the tyre, then slowly cutting into the tube. I'd check the outside of the tyre for tiny cuts, and the inside for barely-detectable points poking through.

This photo shows the sort of small cuts I'm talking about:

Each of those had a little bit of glass or something in it once, but most of those work their way back out. The problem is that the ones that don't usually work their way in instead. If you poke in there with something like the file shown (a sharpened spoke is what many bike mechanics use) you'll sometimes find a ~2mm or smaller triangle of glass.

When those work through the inside of the tyre they don't punch a hole like a nail does, they slowly cut a little slit as you see above.

The way to avoid this is by going over your tyres every few weeks and digging out those bits of glass.

Note that even very puncture-resistant tyres will suffer this, just less often. I've had Marathon Plus tyres puncture this way, but only once (I use those tyres a lot). This guy had the same problem with tyre liners. Picking the glass out is the only solution.

Echoing @DanielRHicks comment: one annoying possiblity is that you have a little fragment of glass or something loose inside the tyre. So every time you check the tyre you don't find it because it slides around as you rotate the tyre checking it, and every puncture is in a different place. So check for that too.


Differing tire sizes on tread and side wall While working on my bike the other day, I noticed that there's what appears to be a tire size on the tread. It says 27.5x2.35

Thing is ... this is a 29 inch tire. It also says so on the side wall, along with the respective ISO number (60-622)

This is a Schwalbe Hans Dampf that was factory-fitted on the bike by the manufacturer (Cube).
Full tire details as per Cube:
Schwalbe Hans Dampf, Addix Soft, Kevlar, Super Gravity, Tubeless Easy, 2.35

The front tire is a Schwalbe Magic Mary that has no such marking on the tread, just the correct details on the side wall.

Can someone explain this? An error in the mold in the Schwalbe factory perhabs? Or maybe the numbers mean something completely different?

It's not at all a problem for me. I know for a fact that this is a 29er bike with 29 inch wheels. I'm just curious.

Looks like an error to me - its either 29" or 27.5" with no ambiguity.   It is unusual to see details embedded in the tread, I've never seen it in person.

You could choose to highlight the correct size details with a white paint pen, and/or file the wrong marking off with some careful strokes of a file.   Or ride till it wears off :)


Is pollution a problem in urban cycling? I usually ride a bicycle in Barcelona. I'm concerned about pollution and I take an anti-pollution mask. Of course, some people scream because they confuse me with Hannibal Lecter but currently that's not a problem.

I've heard a lot of opinions about this: "don't care because pollution it's not harmful", "that masks make no sense" and so on...

What do you know about cycling and pollution? What about masks, are they effective at blocking pollution?

Note: I think objective/documented answers are the most useful. Please, try to avoid "I think that...", "my opinion is..." answers.

Rank, Folke and Jespersen (2001), "Differences in cyclists and car drivers exposure to air pollution from traffic in the city of Copenhagen", The Science of The Total Environment, 279:131-136

  teams of two cyclists and two car drivers in two cars were equipped with personal air samplers while driving for 4 hours on 2 different days in the morning traffic of Copenhagen. The air sample charcoal tubes were analysed for their benzene, toluene, ethylbenzene and xylene (BTEX) content and the air filters for particles (total dust). The concentrations of particles and BTEX in the cabin of the cars were 2–4 times greater than in the cyclists’ breathing zone, the greatest difference being for BTEX. Therefore, even after taking the increased respiration rate of cyclists into consideration, car drivers seem to be more exposed to airborne pollution than cyclists.


Is there a way to calculate the correct bicycle tire pressure? I have 57-559 (57 mm width, 559 mm diameter) / 26"x2.125" tires.
I weigh about 95 kg / 210 lbs.
The tire's sidewall shows a single pressure value of 300 kPa / 43 psi.

However, this calculator shows that given a fixed tire size, different rider + bike weights would have different optimal tire pressures.

Is there a way to calculate such an optimal pressure?

I looked into it and found this PDF: 2004, Berto: "All About Tire Inflation",
where the optimal tire pressures were found experimentally from a Tire Drop test, where

  Tire Drop is the distance that the tire sags under the weight of the rider and the bike.
  For a given tire size and load, the optimum inflation pressure for comfort and rolling
  resistance produces a Tire Drop of about 15% of W (the Section Width) or about 20% of
  H (the height from the ground to the rim).

For my case, that document shows the minimum tire pressure somewhere around 25 psi / 172 kPa for a 26"x2.125" tire.


Long term benefits and risks of bicycling For half a year now I commute to work by bike everyday. It's 30 km each day, about 18.5 miles. I have a good bike, it's comfortable as well as it has good components so I'm having fun riding it. However I found myself wondering about long term effects of riding a bike so often (in average I cover 150 km a week on it).

Considering positive effects I realized my fitness improved a lot, which is quite obvious why. I also feel better about having this regular workout besides my job in an office. So there are both mental and physical benefits. So now I'm just curious: What physical and mental benefits have you noticed from bicycling/commuting by bike often?

I also wonder about risks I could come to face though. Are there long term risks for my health? What other issues might become important after more months/years of bicycling? And of course what can I do to prevent them from getting bad or happening at all? I'd like to avoid typical mishaps and learn from you guys' experience.

Long term benefits ... Hmmm ... does 55 years count as long term? If so, I think I and a few others here qualify ...

Key benefits

Cycling is a life-long form of exercise. One of the group I meet for coffee is 82, another is 80. A bunch are in their sixties and seventies, and another bunch are in their fifties. About a quarter are women. Another bunch I ride with has people from late teens through to sixties. Half are women.
Cycling can be done in a thousand ways. I've seen young professional Italian women cycling to work in high heels, Italian grandma's cycling to meet for coffee, and their menfolk kitted out in lycra for their daily "roll". You can race, tour, commute, shop, goof off, cycle around the world. It can be your only form of transport. You get places faster than walking or running, and see almost as much.
Cycling is low impact (unless you crash). If you choose to cycle with intensity, it is has far lower impact on your joints than activities such as running, jogging, the latest Gym fad, and even swimming (which can be damaging to elbows and shoulders).
Cardiovascular, aerobic capacity, strength, metabolic level. Most of the health issues of today's world are due to too little of these. You are going to be healthier, and healthier for longer, with a cycling life style.
Endorphins (feel good hormones) are released by cycling. You cannot stay grumpy or depressed with a cycling life style.
Office productivity. If you're a sedentary office worker, the higher metabolic rate and higher blood flow will give you more energy at work and higher productivity.
Weight and cholesterol control. The higher metabolic rate produced by regular physical activity enables your body to burn it's way through lots of fats and foods.
Social. Meet a significant other. Whatever.
Bedroom performance. For either sex, bedroom performance is better when you're fitter.
Being quicker than cars through inner city traffic.
Being able to bypass traffic jams.
Idealists may think they'll save money.

Key risks

Crashing, or being crashed. On a bike you are more vulnerable. The solution is to simply take 100% responsibility. See Best ways to avoid getting hit by cars?
There have been medical reports of lower sperm counts among (male) cyclists. This one has always been exaggerated. Your better general health is a far better indicator of reproductive success.
Owning too many bikes, each of which costs more than your car.
Er ... hard to find too many more. Too much vitamin A? Being annoyingly happy with life? Annoying your friends by knowing what a kilometer is?


Speed and the sizes of tires/gears Does the speed of a normal mountain bike vary according to the diameter of the wheels? If it does, will a larger diameter increase the speed or decrease it?

Similarly, if the speed varies according to the size of the gears, will a larger gear (if possible) increase the speed? What are the demerits/disadvantages of such features?

For a single gear ratio turning at a constant cadence (revolutions per minute of one pedal), a larger wheel diameter will have traveled farther/faster. A larger wheel would increase top end speed, a smaller wheel decreasing it.

Gear ratios are gear ratios. For a given chainring tooth count moving at a given cadence, the smaller the gear in the rear the faster the wheel will turn. The larger the gear in the rear, the slower.

Basically, if you took a road bike that was designed for 700c wheels, and put 20" bmx wheels on it, it would be slower at a given cadence in all gears. The opposite would be true if you could increase the wheel size.


How do I check my steel frame for water ingress, and minimise the risk of rust? I have a bottle cage on the upper side of my downtube, and yesterday I noticed that one of the screws has gone missing.  I don't know when this happened, but it could have been months ago.  I often leave my bike parked in the rain, so I'm now concerned that water has entered the downtube through the exposed screwhole and settled in the frame, which is made of steel.

How can I check if there is water ingress and minimise any damage?  My first thought is to turn the bike upside down for a few hours and let any water drain out, but is there a better way and/or more I could do?  I would like to stop any rust in its tracks.

Water will always find a way to enter the frame, if not through the bolt hole then via the seat tube or head tube or gas exhaust holes. Turning the bike upside down will not be very effective unless you fall into a river often. What you can do is 1) make sure that water has regular ways to leave the frame; 2) use special coatings on the inside surfaces to inhibit or prevent rust ; 3) perform regular maintainance to prevent bike parts from binding together.

The lowest point of the frame is its bottom bracket shell. That is where all water tend to come. Check if the frame has a hole there so that water can drip out.

You will need to strip your frame before applying a rust inhibitor. See a good guide here: https://surlybikes.com/info_hole/spew/spew_care_and_feeding_of_your_steel_frame

Lastly, you should put grease at the places where the frame holds other parts: bottom bracket threads, seatpost, quill stem (if you have a threaded one ). That would prevent parts rusting together, making it impossible to detach them later.


Why does my front shifter take so much effort to get into 3rd? I'm trying to get my son's bike dialed in.  We bought it used and it's not quite right with respect to the front shifting.  I got the front derailleur stops adjusted properly so it limits at the right place when moved by hand.  I fought with the cable tension until it was able to shift into 1st and 3rd, but even so, it takes an incredible amount of force to push it into 3rd. Specifically, I push with my thumb and it clicks into 3rd at the shifter, but I need to push a little past to get it to actually shift. Pushing out of 2nd into 3rd, it resists strongly such that my thumb actually hurts from debugging this.  I don't think my 12 yo will be able to do it.  What might I have done wrong?
It's Shimano STX, thumb/finger shifter.

It is difficult to say without physically seeing the bike and the integrity of the cable to the derailleur. One thing, I can think of is that there could be too much slack in the cable, which is why there is the need for an extra push. However, with a triple chain ring if you have a good shift from inner to middle that perhaps is not the case.
Also to go from the inner to outer chain rings you are putting tension on the cable, which is why you feel the effort more as you go from inner to outer chain rings.
I will say on my road bike and a long time ago on a kids mountain bike with triple chain rings I do recall when going to the largest chain ring it was not like a click + shift, but a longer push and shift similar to what you are describing (i.e. I shifted and had to almost push the shifter more to put enough tension on the derailleur to move into the new chain ring).
Most local bike shops will be able to do a quick safety check on the bike and perhaps can tell you if it is normal. That is probably where I would start.
Hope that helps.


Are flats more likely in hot weather? It has been very hot lately, up to 106 and 103 degrees F (41 and 39 degrees C).

I went for a ride and got a puncture flat both times.  I don't usually get flats. Is it possible the heat of the road makes the tire rubber softer?

I'm running continental grand prix 4 season. I'm thinking because the cold weather compound its more susceptible to heat?

Or just coincidence?

This is a matter of some debate. The New York Times article "Does Hot Weather Cause More Bike-Tire Problems?" by J. David Goodman (July 22, 2010) may be of interest.

The claims in support for hot weather causing problems are that the tubes may be running higher pressure than designed, or the rubber softening making it more permeable. I, like many others, don't believe these claims hold water (however, I don't have appropriate test rigs or the will to verify this).

The biggest flaw with hot weather causing problems is that tires, tubes and rims are tested at pressures way past whats on the label (and for almost all riders, they should be using pressures way lower than the label). So, you're likely quite far from the limit of failure. 100 F isn't an unreasonable summer temperature for a large number of people (the Southwest, particularly), and it would be ridiculous to engineer a tire that couldn't reliably last at 110 F air temp riding conditions, since that would give a very small margin of reliability.

However, I wouldn't necessarily call it a coincidence. In summer, your mileage increases versus winter, and you're likely to see more road debris (from drivers, liter, etc.). Compounding the increased mileage with tubes and tires that may not be in great condition could see an increase in flats.


How to recognise a 6-speed freewheel compatible hub? I need to change the freewheel and the hub on my road bike and have been looking for a suitable replacement. I wish to keep my rim so I will rebuild the wheel. Also, I want to stay with a 6 speed cassette due to the limits of my current derailleur.

It seems easy to find a 14-28 6-speed freewheel. However, I haven't been able to find a 6-speed freewheel compatible hub, or at least one that states explicitly such compatibility.

My question is:

How do I know that a hub is 6-speed freewheel compatible? What measures do I need to look for to make sure that the cassette will match the length of the hub?

Here's an example of a frewheel that I'd like to match with a new hub http://www.ebay.co.uk/itm/SHIMANO-6-or-7-SPEED-FREEWHEEL-14-28-TEETH-SCREW-ON-NOT-CASSETTE-REAR-WHEEL-/121300234787?pt=UK_sportsleisure_cycling_bikeparts_SR&var=&hash=item1c3e0eb223.

All freewheel hubs have the same thread and are compatible with single, 5, 6, 7 and maybe some 8 speed freewheels. Position of the hub is set by dishing of the wheel and spacers on the axle. It's an interesting question. But I think that you should worry more about the rear spacing. 6 speed modern freewheel is not considered to be wide comparing to ones with more cogs. I wouldn't worry about this, just in case stay away from track hubs which are designed for single speed freewheels. I'm upgrading a 1980's ten speed bike now by replacing old 5 speed freewheel with 7 speeds to match new indexed 7 speed shifter. Previously I put 8 speed freewheel on that wheel but I had to add spacers to spread the seat stays a bit. It worked with original friction shifter but I don't like it.


Can e-bikes speed up my commute? Which class? I have a daily 15 mile commute (1-way) which takes me approximately 1hr 15 min each way if I bike (taking into account traffic signals and so on). The route is all surface roads, with some mild hills. Sweating on the ride to work isn't an issue as my building has a shower and I don't feel particularly tired after. However, the sheer amount of time it takes each way is the main reason I don't bike every day; I'd like a commute that's more in the region of 45 minutes each way. I would like to cut my travel time. Therefore, I'm considering an e-bike purchase and am wondering the following:

Class 2 bikes go up to 20 mph with throttle and the saleswoman told me that pedal + motor could take it over 20mph. Is this true? On a Youtube video I watched they said something to the effect of "the motor stops helping after 20mph". Does that mean it shuts off once your speed goes over 20mph, leaving it entirely up to your muscle power?
Class 3 bikes go up to 28 mph per my understanding. Since I don't take bike paths on my commute they are legal (I live in California). Should I be considering a class 3 bike instead of a class 2 if my goal is a faster commute (as opposed to not sweating or getting tired)?

Based on comments, here is the question I'm actually trying to have answered:

Are class 2 bikes useful for going more than 20 mph consistently? Or is class 3 better for me if I want more speed?

Example class 2: https://electricbikereview.com/genze/sport-e101/

Example class 3: https://electricbikereview.com/juiced-bikes/oceancurrent/

Of course an ebike will be less effort and leave you less sweaty. And of course the faster the bike, the shorter the commute.

Class I: The key thing about this is that it's pedal assist only. The motor will only turn on while you're pedalling -- and it'll cut off at 20 mph -- so going faster than that will require you to pedal. Going downhill with a backwind and pedaling like a demon, you could feasibly go 40mph or faster.

Class II: These bikes have a throttle (combined usually with a pedal sensor) so the motor can turn on without pedaling. So you can go from 0 to 19.9mph without pedaling. At 20mph, regardless of whether you're using the throttle or pedal-assist, the motor will cut out and you'll have to pedal to go any faster or to maintain speed -- note that these bikes are usually heavy so even pedaling you're more than likely to quickly lose speed back down to 19.9mph unless you are pretty buff or you're going downhill. Technically, Class II  are limited to 20mph for electric assist but it's often possible to bypass that control with a firmware upgrade or setting in the control panel.

  Speed Limiters: On most Class I and II bikes, the speed limiter is a hard cutoff. The motor can give you 100% power up until 19.9 mph and then when you hit 20.0 mph, the motor gives you 0% power and you have to pedal to maintain speed. The bike usually quickly loses speed (as pedaling a heavy bike at 20.0 mph is non-trivial) and the motor kicks back in at 19.9 mph. This can cause some jerkiness around the speed-limiter zone especially if you were using pedal-assist because the bike suddenly gets very heavy at 20 mph (it's not as noticeable with a throttle, where it just feels like the motor is cutting in and out).  More expensive bikes will more smoothly ramp the power down: 100% power at 19.0 mph; 80% power at 19.2 mph; 60% at 19.4; etc. etc. and then smoothly ramp the power back up while  you're accelerating.

Class III: These bikes have a throttle (combined usually with a pedal sensor) so the motor can turn on without pedaling. These are limited to 28mph for electric assist but it's often possible to bypass that control with a firmware upgrade or setting in the control panel.  For example, some are sold with an "off-road only" switch.

All of these are limited to 750 watts of electric assist power as well. For more info: https://electricbikereview.com/guides/electric-bike-classes/


I'm lost with all the names of bike parts flying around! Ok so I've been riding bike since I was as young as I can remember. Now I'm 18 and I've been given a fixie. But I know nothing about bikes I've always just ridden them and brought them to a shop when they broke. The fixie I have is basic and when people ask what ratio I run and other things like, "What cogs have you got?". I've tried searching online but I can't find a definitive guide to fixies. Can someone please give me a basic run down of how to improve my lingo and understanding of bikes.

See the terminology index. It doesn't apply just to fixies, but a lot of the parts on either kind of bike are the same.


How should I remove a tyre that's stuck to the rim with old sealant? I have a wheel with a puncture. It seems to be a pinch flat (the air is shooting out in the direction of the rim) but I can't get the tyre off to investigate.

This is an ex-tubeless tyre that I put a tube in once. Guess I should have cleaned up the sealant first. Now I can't even move the tyre, let alone remove it.

The rim is aluminium. Is there a powerful solvent that is safe to use, that would weaken the old Stan's + muck glue?

I googled around this, and most answers are 'be a man! use tyre levers! No, they're for girls, use your thumbs!'.

Well, I'm beat. I have poor muscle tone and bad motor skills for medical reasons, so I accept the possibility that 'normal' people could just pull it off. I, however, can't. The suggestion here was use a credit card but that didn't work.

I could take it to the bike shop, but something tells me this isn't the last time something like this will happen. I'd like a solution for next time. I need a solvent that won't attack the aluminium. Ideally I'd like to save the tyre/tube, but that's a bonus.

Edit: whoever suggested a vice, that worked. It unstuck the tyre and I could remove it normally with tyre levers.

Before looking for a product to solve the problem, try this. Many tubeless rims grip the tire very tightly when one is just trying to push the tire very inwards to unseat it. The trick is often to push the bead section more straight down in the direction of the rim well, with a slight scooping motion inward.

Sealant isn't glue and doesn't have all that much tensile strength. It's usually the case that you're more up against the mechanics of how the bead locks in place.


Do studded tires make less than ideal railroad crossings worse? I'm considering getting studded tires, but I'm concerned about a portion of my commute.  I go down this road both directions: 39° 40.468', -84° 14.340'.  This 2 lane narrow road has 2 railroad crossings from a parallel track next to the road in order to service a factory.  Both the road and the crossings are poor quality.

Considering the rule of thumb for railroad crossings is perpendicular as possible, this road doesn't allow that.  I'm not talking about the tire falling in the groove along the rail, just the tire trying to climb a rail.  On dry days, no problem, but when they are wet they cause a small slide to the side before the tire goes over the top of the rail.  What I'm worried about is that since the tire engages the track off center, will studs cause me even more troubles by not providing traction to climb the rail and cause the bike to slide out from under me as the tire follows the rail?

In my case, the bike is a 2008 Schwinn High Timber, 26x1.95 inch department store mountain front suspension with stock dirt trail tires.  Any tires I plan on buying are urban 26x1.50 to 26x1.75.

I think you'll be fine. You might experience some slip, but not enough to cause you to come off the bike or get stuck, etc.

Three reasons I'll think you'll be alright:

Your tires are also made of rubber, not just metal studs and will deform while on/around the rail. This means that some portion of the rubber tire will be contacting the rail and providing grip.
If you have any speed at all your tire will cross the rail quickly and not spend much time trying to grip it.
The odds of both tires being on the rail at the same time, for any length of time, are pretty low, so the rear tire will be pushing forward or the front will pull enough to get you across it.

Now, there's a small technique that will help you out regardless of conditions and tires: the bunny hop. By lifting even your front tire over the rail, you've eliminated half of your traction problem. Getting the back tire up will pretty much erase the issue all together.


Is it normal to stop so much because of thighs burning? I've taken up cycling because of an operation I had in August 2015. My consultant made it clear I had to get regular exercise.

I thought cycling was probably one of the best exercises I could do.

I'm finding it so hard on hills, even a gentle uphill slope.
Very painful butt and aching, burning thighs.
The butt I can live with. But the combination of both stops me from wanting to go out.

My last ride was 17 miles. And 24 two days before. Combination of all gradients.
Not far into my ride, I hit a gentle uphill climb and my thighs started burning. I tried to ignore it but had to stop for a minute then go again.

It seemed I was resting longer than I was cycling. Probably about 10 revolutions. It seemed ridiculous.
I'll be 57 in two days time.

Is it because I'm new to cycling, and my age?
Maybe I'm doing too much? Is it normal and does it get better with practice?

More than likely it is normal and frankly your legs probably aren't used to it. 17 miles is a long way for a beginner so I would pat yourself on the back for that.

You may also benefit from a proper fit from a bike shop. As a lot of beginners either have their seat too high or too low which can limit your power and actually cause you to tire quicker, although a fit takes a lot more into consideration that just that. Either way it would probably be worthwhile to at least look up a good guide and check your posture, it can make a big difference.

Regarding your age, I am 32, and know several people in their 60's that could leave me behind going up hill (or anywhere) with ease.

I am in okay shape, and have been riding off and on for several years and still have to stop from time to time. It does get better though.

You may also take a look at your diet and pre-ride foods, it is also important that if you are going on a long ride you take some snacks for along the way so that your body has some fuel to burn. Eating 30 minutes to 1 hour before a ride vs not eating at all can make a monumental difference.

Bottom line you have made a healthy choice and a fun one to improve your own health and way of life! Keep at it and don't give up or feel bad if you need to stop and catch your breath from time to time, the most important thing is you are out riding!


Converting Mountain Bike for Road to complete in 33 mile mini triathalon I have a very good mountain bike and like to ride trails.  I recently signed up for a mini triathalon that requires a 33 mile road ride.  I don't want to buy a new bike, so I was thinking about buying a new set of rims and swapping them out for this race.  Not very experienced with converting, so looking for some help on solutions.  Don't want to spend a ton of cash on this either.

Even if you do not go as far as different rims, consider different tires.

Slicks (1.25") vs the regular tires (2+ inches) will make a huge difference, and usually can be found for $30 a tire or so in the US or Canada.

Beyond that, remove unnecessary hardware.

Front shocks are probably the worst thing you might have on the bike.  I do not know if it is worth considering a hard fork just for this race or not.


L Limit screw can get front derailleur close enough I am following the instructions on here:
https://www.parktool.com/blog/repair-help/front-derailleur-adjustment
And they say:
"Sight gap between inner chain plate and inner cage plate. Only a small gap should be visible, about 1/16″ or 1mm, about the thickness of a dime."
"If the gap appears larger than 1mm at its widest point, tighten the L-screw, in small increments, until the gap closes."
But I've tightened the L screw all the way and there is still a massive gap....? (I can make the gap larger by loosening it but obviously that's not what I want)
What have I missed?

What I was missing was that the screw wasn't fully tightened but it was impossible to tighten the screw whilst the derailleur was against the limit and the cable was tight. Pulling the cable to move the derailleur and tightening the screw at the same time worked fine. Totally slack cable would have been fine as well I think.


Can a fixed gear sprocket be changed without tools? I do not have a chain whip or sprocket ring tool. Is it possible to change the rear sprocket without these tools?

For the lockring a hammer and screwdriver works sometimes, but you end up damaging everything involved except the hammer, sometimes to the point that you can't get the lockring tool to work after the fact.
Get the lockring tool. There are semi universal ones that work ok. The type that are designed to fit specific lockrings (ie 3 slot, 4 slot) work much better. Either way they're fairly cheap. Once the lockring is off you might be able to use your bikes chain and crank in place of a chainwhip, but this is yet another place where you're better off just buying the appropriate tool. Once you have them you'll be a happier fixie rider.


warm up without bike Next weekend I'll participate in a relay triathlon (1100 mts. swim, 7 kms. run and 13 kms. MTB). I'll be doing the bike section, which is the last. Bike needs to be at the boxes area an hour before the start of the race. I guess I'll start riding about 40 minutes from the start of the race. That's around 100+ minutes since I leave the bike at the box. What can I do to warm up during this time or to start at full power without needing to warm up? I thought about riding a few kms. before parking the bike at the boxes, would it be effective after such a long break?

Thanks in advance!

If possible, borrow a second bike, and perhaps a trainer. There is very little that you can do to effectively warm up in a cycling effective way, other than ride. A light jog, and some stretching is the second best option.

It is a short enough ride for that to suffice, if it is your best available option.


Are road bike seats interchangeable? I am a beginner to riding on road bikes.  A friend has lent me his road bike (Giant) for about 1 month and I want to use it as much as possible before I think about buying my own.  The current seat is absolutely killing me though (I have padded bike shorts already) so I'm thinking of fitting it with a seat more suited for me.

If I get a new seat, is it likely that I will be able to use it on another bike?

Almost all saddles will be exchangeable -- there are a few rare (and very expensive ones) you wouldn't encounter unless you were looking for them which can't be exchanged.

So yes, almost surely if you buy a new saddle you can use it on another bike.

Note that some saddles are marketed as "road" or "mtb" - the mtb ones are possibly more durable, but this is a marketing distinction -- they are not separate standards.

That being said, there are a few things to note in your question:

1) Some discomfort when starting to ride road bikes is normal - the saddles are often harder than what most people are used to, so they need to get used to using their sit bones.

2) Some seatposts don't have much adjustability for saddle angle and position. Thus, a poor seatpost in this respect may make a good saddle for you not feel good. Brooks saddles, for example, are somewhat notorious for needing a decent amount of adjustability in the seatpost.

3) Make sure your bike is fit to you - if the saddle is in the wrong place (or other aspects of the fit are wrong), it won't feel good.

4) You may need a different saddle (as you assume).


Real measurable benefit to ceramic bearings? Is there a real difference between riding on ceramic bearings and riding on stainless steel?

How would you measure it? Does it require it to be every bearing in the drive train, or will each set of bearings replaced improve performance?

Does anyone have real world experience with them to relate?

Edit:

I don't know if it matters on the bike, but I saw this today. If this is an indication of the difference in the level of friction resistance ceramic offers, then I'm in.

In the video:

The left pulley shown is Shimano DuraAce, the middle one is Campagnolo Record 11 speed. All three pulleys are fixed to 5Nm of torque at the axle bolt. And all 3 three have at least 1mm of play at the pivot, so there is no extra tension on the bearings compared to normal install in a derailleur. There is a difference in movement of about 18 seconds of spin in the video. It's crazy.

The short answer to your first question is "the power savings from using ceramic bearings compared to good steel bearings is almost zero." The short answer to your second question is "yes, it is possible to measure the difference but it's not easy." The longer answer, and the support for the shorter answers is below.

First, however, it depends a little on whether you're talking wheel bearings, or bottom bracket bearings, or both. If you're interested in measuring the difference, the way you measure differs for the two. BB bearing drag would show up in differences in drivetrain efficiency, while hub bearings would show up as a component of rolling resistance. The difference, of course, is that drivetrain losses only occur when you're pedaling, not while you're coasting, while rolling losses occur as long as you're rolling, whether pedaling or not.

You can measure differences in no-load hub bearing drag by holding the wheel up in the air with a fork, using a home-made speed sensor jury-rigged with a reed switch connected to a digital voice recorder. You spin the wheel up, then record and calculate the difference in timing "clicks" as the wheel decelerates. Swap bearings, lather, rinse, repeat.

However, this would be in a no-load setting and you might think differences in bearing drag might be amplified in load-bearing situations. If so, you'd have to test that way. You could do it in the lab but it's also possible to do yourself, in the field, with the jury-rigged speed sensor.

First some background. The rolling component of drag is typically measured by the coefficient of rolling resistance, Crr (the coefficient of aero drag is Cd, which is usually multiplied by the front surface area, A, and described by the combined term CdA). Crr can have a speed-dependent component but at cycling speeds this is negligible so we can assume Crr is constant. If so, the power demanded for moving a bike and rider at a given speed is pretty well known and understood: rather than go through it all here, I'll point to a (um, brilliant) method that allows you to estimate CdA and Crr which can be found here.

Now, if you do all of this, you'll find that for a typical bike, the total overall Crr from all sources (tires, tubes, hub bearings, and typical "smooth" road surface) of around .005. The Crr for really good tires on that same surface might be .0045; for really lousy tires the Crr might be .006; and for a really rough surface the Crr might go as high as .01. And, some context if you look at the power equation linked to above, you see that Crr scales exactly like gradient in its effect on power so when the Crr is .01, the effect on power is exactly like climbing a 1% grade. Likewise, an increase in Crr of .001, due either to a different tire or to putative bearing differences, is just like climbing a grade 0.1% steeper.

Here's one more fact, also derivable from the link above: a rule of thumb is that at 25 mph on a flat hard surface, a cyclist in good aero position needs around 250 watts (an exceptional aero position is achievable with under 200 watts). At 25mph, a difference in Crr of about .0005 is roughly equivalent to a difference in power of 5 watts. That is, a difference between a good tire and a very good tire is worth about 5 watts at 25 mph.

If you have done any field-testing of bicycle drag you'll realize that 5 watts difference in rolling resistance is pretty noticeable. Riders report that the difference between using ceramic and steel hub bearings is not noticeable.


How to pull a carbon seatpost out of a carbon frame? How do I pull out a carbon seatpost on a carbon frame?
It seems so hard for me...
Do I need a special tool, or just ask help from a local bike shop?

done with the seatpost.
I made the frame and fork reversed hold the bottom bracket with my tripod, install a saddle on it and gave a big bang on the saddle about 20 times and done.

For Aero seatposts, smack the saddle nose solidly sideways with your hand, you should hear a loud crack, this is the surface tension breaking.  Seatpost should then move OK.  Saw this done by ex-Pro who was Giant dealer on a Propel, made my life so much easier since I learned that tip


can only use right hand to brake reliably, due to disability - safer/possible to modify bike? I'm new here and hoping someone might have thoughts on this - had a look and couldn't find an answer elsewhere! Apologies for the kind of long question, and if it's silly, but any thoughts would be appreciated :)

My situation is this: I ride a simple hybrid bike just to and from work/uni most of the time, though I'd like to get a road bike one day. I  do also like "mountain" biking on flat trails but borrow bikes for this.

I have very mild cerebral palsy on my left hand side. It affects muscle strength and fine motor skills but only slightly. If I wanted to apply the rear brake, on my left handlebar, it's difficult for me to get up enough force quickly. (steering and controlling bike are totally fine)

I'm great at using the front brakes though, and it's never caused me problems before (I don't go that fast anyway), but I just started wondering, if I want to get a road bike or do more risky mountain biking, perhaps I should consider what's safest and whether modifications would be possible.

So firstly I'm wondering whether anyone thinks this is worth investigating, or if only front braking should continue to be fine.

Secondly, if I should try find a way to rear brake, does anyone have any suggestions? Is there any way to control both brakes from my right handlebar (I'm pretty quick and strong on my right, due to always having had to compensate for my left)? Also, when I was a kid, my dad used to find/make me bikes that applied rear brakes when I back-pedalled - is that a thing? (Google directs me to coaster brakes) But I can't remember if I also had a front brake on those bikes.

I'm not good at DIY, due to the lack of fine motor skills from one of my hands, so if I want to go the path of trying a modification I guess I also want to try work out what I'd get charged for it by a store here in Australia.

I may just be overthinking this, but I've always felt kind of nervous on road bikes (only ridden my boyfriend's a couple of times), so if I do want to get into riding one, I want to know I've got the best set up for me.

Thanks so much!

(also my injury tag  = disability, wanted to create the tag but couldn't due to being new. I felt it might be useful to link it to injury anyway in case someone looks there for answers on how to ride after an injury to a hand)

Generally speaking your off hand should be the front brake, so if you're right handed the front brake should be the left. They can be set up either way, though, especially if you're using cable-driven (non-hydraulic) brakes. Even with hydraulics you should have no problem making the right hand brake the rear. I would highly advise this, as in a panic situation while mountain biking if you grab the front brake hard, you're more than likely going over the bars.

There are levers that work both brakes. They are out there!

Here is one that pulls 2 cables at the same time, so you could use it to pull both the back and the front brakes.
http://www.jbi.bike/web/checking_product_description.php?part_number=13748

There is also a company called Surestop whose product I believe works off of one lever and won't engage the front brake until the rear is already engaged, thus making it very difficult to catapult yourself over the bars. They are for V brakes only though, I believe.

The backpedalling braking is indeed a coaster brake: you are correct on that note.


What do I have to know, to replace my hydraulic disc brakes with new ones? I want to buy a new hydraulic disc brake for my old mountain bike, which already has a disc brake. As I am very far away from any bicycle shop I want to buy the parts on the internet. The shipping costs will be high, so I don’t want to send anything back.

There are different standards to mount the brakes to the bike. Post mount and IS2000, and I have heard that post mount has different sizes/types, e.g. post mount 6 and 7.

Now what I want to know:

What do I have to check or measure to be sure, that the new brake fits my bicycle?
Which adapters do I need (depending on the size of the discs and the type of fixation of the calipers)? Especially, when the new brake has a different disc size than the former one?
Which screws? Are they standardized and fit on all bikes and brakes independent of bike and brake manufacturer?

I want to know this in general, because I also want to replace the brakes of a friend’s bike with hydraulic disc brakes too.

(within reason) Any disc brake will fit on any bike with the right adaptors.

The adapter you need will be based on the size of the rotor (disc) you want to run, the mounts you have on the bike (IS/post) and the brake you're trying to fit. Most callipers will have post mount fittings so require a adapter to fit to any IS mounts. Most frames still have IS mounts on the rear, while most newer forks have post mounts. They can be identified through how they are orientated, post mounts go into the fork or frame, IS mounts are orientated the same as the bikes axles.

When purchasing brakes Shimano callipers come separate of rotor and mounting adapter, Avid comes pre-packaged with everything so you simply buy the size you require. Smaller brands vary.

You need to be aware that the size of rotor makes a difference and some forks/frames are only rated up to a certain rotor size; any larger could cause the parts to fail.

There are two different standards for fixing the rotor to the hub - standard 6-bolt and shimano centrelock.

The bolts are standard thread (for all examples I've seen) but the length will vary for post mount brakes. You need to ensure that you use the correct length screws for post mounts. Short bolts can (some say will) lead to catastrophic failure.

The other point to bear in mind is that the hydraulic hose length for the rear brake may have significant extra length (c.300mm) and requires a moderate level of technical skill to shorten. The rest of the install can be done by hex wrench and T25 driver/wrench. A torque wrench is recommended but not mandatory. Other considerations will be cable routing, securing the hose and whether the brake mounts need facing.


What can I use to replace a Shimano Deore LX RD-M581? I've got a trusty Marin East Peak XC from 2008, but the rear derailleur's adjustment screws have all sheared and I need to replace it. The derailleur is a Shimano Deore LX RD-M581, but I can't find any exact replacements available.

How can I find a derailleur that will work?

I've found this extra info for my bike:

Rear cogs: 9 speed, 11-32
Chainring: 44/32/22
So the total capacity required is 43
I'm not quite sure if the current is GS or SGS

I've seen some advice that I can could get the right modern Shimano derailleur with 7 or 8 speeds, like an Alvio RD-M4000? I'm not particularly fussed about ultra-high quality or anything, I just need something that'll work well. I'm also a student though and can't really afford to screw it up and buy multiple versions.

You can in fact use any modern Shimano derailleur for 7, 8 or 9 speeds that meets the total capacity and largest sprocket requirements. The reason is that Shimano used the same cable actuation ratio (ratio of cable length pulled to lateral cage movement) for MTB groups below 10 speeds.

If you want a derailleur that works as well as possible, get the current highest level 9 speed option. That would be the Alivio RD-M4000 which accommodates 32 to 36t largest sprocket and total capacity of 45. Rear derailleur specs are here: https://productinfo.shimano.com/#/spec/MTB/Rear%20Derailleur. You can look up various options.

Note: when I accessed that page there appeared to be many errors, so Shimano might be in the process of an update. Correct info can be found in the archive PDF files here: https://productinfo.shimano.com/#/archive.


In shared bicycle/pedestrian facilities next to a road, do I obey the pedestrian or the vehicle traffic control devices? My commute takes me on a bike path that runs parallel to a road (with a sidewalk in between). When crossing other roads, the sidewalk and bike path merge, and there is one curb-cut and cross walk with a pedestrian signal. Unless you actually press the button to cross, there will be a green light on the parallel road but a "don't walk" signal for the crosswalk. Should I go anyhow? Should I come to a full stop before doing so, or simply slow down to pedestrian speed and check carefully for turning cars before doing so? Or should I press the button and wait for the pedestrian light?

I'm trying to figure out how "same road, same rules" actually works in practice; the problem is, there are no specific rules for bicycles on bike paths which share crossings with pedestrian crossings, and of course you can't apply the same rules as for cars since cars can't use bike paths.

To clarify, since there seems to be some confusion about the setup of the intersection, there will sometimes be a green light on the road parallel to the bike path, with a "Don't Walk" sign for the crosswalk, and there will sometimes be a green light on the road parallel to the bike path, with a "Walk" sign for the crosswalk (possibly based on whether someone has pushed the button, or possibly based on the timing, I'm not sure). That is, there are times when there's a green light on the parallel road, and cars may turn, but pedestrians (and presumably bikes) are encouraged to cross, and some times when there is a green light on the parallel road, cars may turn, but pedestrians are encouraged not to cross.

Honestly, I think that's a crappy design for a bike path, and I would just ride in the road instead.  A bike path like that is great for a weekend ride, but for a daily commute, it just wouldn't cut it.

If that road isn't safe to ride in, I'd try to find a different route.  And if that's not an option, I suppose I would probably ride against the pedestrian light, slowing down to make sure it's safe to do so.


Converting a 3x10 to 1x10 with QR dropouts (NOT Thru axle) Wondering about the load and potential issues of converting a 3x10 to a 1x10.

Bike is aluminum with QR axles.

Should I worry about the rear axle twisting out of the dropouts on the higher gearing?

Dropouts are vertical.

You should have no issues from a frame stand point. Just make sure you keep a good chain line and you're good to go!

There are lots of 1x10 QR bikes out there. And with the popularity of the 1x10 these days your options will be abundant. Also you will want to look into Narrow/wide chainrings for the front if you haven't already. With a good one a chain guide is not necessary unless you're doing downhill stuff.


Fixing rear-wheel puncture on belt-drive bike I just bought a bike that has a Gates Carbon belt drive and am wondering what I will need do to remove the rear wheel when I get a puncture in my rear tyre away from home.

The dropout looks like this:

The centre part of the dropout on this side of the bike (and not the left side) is clearly removable. The rear of this removable dropout has a triangular shape that wedges it in place.

My guess is

Disconnect brake cable to allow room for tyre to pass them.
Disconnect shifter cable from hub.
Do nothing with the belt tensioner? Loosen it?
Loosen nuts holding rear axle.
Remove two recessed Allen (hex) bolts from removable dropout
Pull the frame apart slightly so the dropout can move forward?
Move the belt out of the way through the now open slot in the frame.
Pull the wheel out rearwards.

I don't like step 3 a lot. I've read the belt tension is important and I'm not confident of getting it correct when replacing the wheel. But if I don't loosen the belt tension first, step 6 may cause damage.

Is this procedure correct?

It looks good except I think you will have to loosen the tensioner. You won't have to spread the frame. When the recessed allen head bolts are removed you risk damage to the very end of the threads due to the belt tension. It is unlikely you can reinstall the tensioning assembly with tension on the belt. Due to the complexity of this kind of flat repair you may want to consider some type of puncture prevention be it tires, tire liners etc. I have used a technique of repairing a puncture without removing the wheel. In this case a rider on my local trail had a flat, bolt-on wheels, and no wrench.  You flip the bike upside down. Work one edge of the tire off the rim. Pull out the tube and patch and replace as usual.  Instead of working your hands around the wheel you spin the wheel as you work your way around. It appears in the photo that you may not have to remove the shifter cable. There may be enough slack to work it around the frame and effect the repair.


Is there any bicycle that can fly? In E.T. the bicycles fly. In old films we see some inventors try to construct a bicycle which flies, with wings similar to a bird's.

Yogi bear has a flying ship.

See the picture above the site.  The rider is at top of the hill. but if the bicyle could fly he could go anywhere, like Willy Wonka's elevator.

Has any flying bicycle been invented yet?

The first human-powered, fixed-wing aircraft flew in 1961, the SUMPAC. Several other such craft were flown in the 60's and 70's, including the Gossamer Condor, which won the prestigious Kremer Prize for human-powered flight. All of these were powered by a human pedaling, like on a bicycle.

An aircraft with wings that flap like a bird's is called an Ornithopter. None that I can find were capable of getting into the air on their own. Early, unmanned ornithopters were powered by large rubber bands or gunpowder charges. The first verified human-powered ornithopter flew in 1929, but it too was towed into the air.