Upgrading From Shimano 8 Sp Alivio To Shimano 9 Sp Altus I have an old giant warp D's 2 bike that's about 10 years old. I've maintained it and it still rides good and looks just as good. I wanted to upgrade from the old alivio 8 speed drivetrain to either a new alivio or altus 9 speed ddrivetrain but wasn't sure if the cassette would fit on the freehub on the bike and I didn't want to buy the components and then found out they couldn't fit and then be stuck with useless parts. Could somebody please help the old man stuck in a rut?

A 9 speed cassette will fit on an 8 speed hub. The extra gear is accommodated using thinner cogs and spacers.  You will also need a new shifter as its the shifter that provides the indexing for the gears. If you also increase the range of gears (increase the largest cassette cog), you may need a new rear deraileur.

Its possible to run 8 speed chain rings with a 9 speed chain, but you will get better shifting upgrading the chain-rings. In this case, replacing the entire crank set might be cheaper.

There would be little advantage replacing the deraileurs (especially the front) unless they are worn out.


after heavy rain or washing, which parts of the bike to re-lube and with what? Good afternoon,

I'm a relatively new cyclist and I've been caught out in a heavy rain a few times recently.  After this, or if I was to wash my bike thoroughly, I'm not sure which parts of the bike to re-lube and what lube to use.

Obviously I should clean and re-lube the chain, but what about everything else?  For example in this video:

at 7:30 the presenter, after re-lubing the chain, shoots the front and rear derailleurs and adjacent parts with WD-40.  This seems backward to me, being that WD-40 is also a solvent I would have figured to clean the chain first, then shoot the front and rear derailleurs and adjacent parts with WD-40, then re-lube the chain with chain lube.

I've checked various other YouTube videos and websites, many suggest similar to above, but others recommend to re-lube each pivot point of the front and rear mech parts individually with chain lube.

Also, in the above video the presenter shoots the metal brake parts with WD-40.  This seems to make sense with rim brakes, but I've recently changed to a bike with disc brakes (cable, not hydraulic) and I'm apprehensive about spraying WD-40 or anything else near the relatively small and delicate brake pad friction material surfaces.

Can anybody suggest a recommended re-lubing procedure after heavy rain or a wash (pertaining to brake parts, please clarify advice for rim vs. disk brakes), thanks!

Edit: somebody linked this: Post Rain Ride Wipedown
which contains similar advice but does not state clearly which front or rear mech parts or brake parts to lube after a heavy rain and with what type of lubricant.

The chain is the big one where you're going to notice a clear difference if it's not lubricated correctly. Even then, how much rain it takes to actually wash out the lube depends entirely on what you're using and how much is on there. Over-lubricating your chain is one of the most common mistakes in bike maintenance. Particularly if you're using a wet lube, you want to know what a dry chain looks and feels like and re-lube then, but not much before. Dry lubes are less sensitive to this - because their liquid part is mostly (depending on the exact lube) a volatile solvent that just evaporates, over-lubricating or haphazard technique won't result in the chain being a sticky mess, or at least not as readily.

For derailer and caliper brake pivots, the differences are mostly incremental. Lubricating them will make things a little bit smoother and is a nice way of keeping things working their best, but usually won't make the critical difference in whether they work period. I do it by putting a drop of light viscosity wet lube like Triflow or Dumonde Lite at each pivot, and I use that pretty much regardless of riding conditions. I find that thick oils don't wick in there very well and dry lubes don't stand up to rain very long, although they're fine in a pinch or for dry riding. I also put a drop at the gap of each RD pulley to help prevent squeaks. That's a spot that can be over-lubricated, but a drop or two is good in general. Some pulleys are much more squeak prone than others. I generally don't lubricate mechanical disc caliper armatures because the actual pivoting surfaces are pretty far down in there, and often it's a cartridge bearing anyway. Lubes that are designed to wick and migrate freely are also a good thing to avoid getting anywhere near a disc brake if you can help it.

The big problem with getting aerosols involved anywhere is it's very easy to get lube where you don't want it, like rims, rotors, and brake pads. In the case of blasting entire brakes and derailers to lube the pivots, you're leaving some kind of oil coating on everything else, which will gather dust if it's dry and get washed off (potentially onto your braking surfaces in the case of a rim brake) if it rains. That said, a lot of people do it to derailers with no real ill effect, although I'd still recommend careful technique, and using a rag to shield everything else. As for the video you link to, you can actually see him hit his rims with the WD40 when lubing the RD, and lubing brakes that way is really asking for trouble. WD40 itself is a reasonable lube for pivots as the solvent part evaporates and leaves an oil coating behind.

The other piece of this is cable lubrication, which can be one of the more pedantically controversial topics of internet bike mechanical discussions, and also an area where what works best is most bike- and conditions-dependent. Lubricating cables always introduces some propensity for them to attract grit, which has lead some to say just don't do it, especially since modern housings have slick plastic liners. While over-lubricating or using the wrong lube can certainly cause problems, I find that 9+ speed bikes with normal non-continous housings need it on their RD gear cables at least to work right consistently, particularly in the rear RD housing loop. I live somewhere where rain is ever-present, and my preferred housing lubes for all bikes are the dryest and least sticky of dry lubes, like White Lightning Clean Ride (formerly White Lightning) or Finish Line Dry (formerly FL Tef Plus). I find that these don't really ever cause problems to speak of with drawing in grit. Using a very tiny (like half a pea) dab of very light, slick grease like Slick Honey on gloved fingers to coat the cable under the RD housing loop also works well in wet environments, again because it's a bit of a potential trouble spot and having something a bit more tenacious works well. As it relates to the question, I'm not saying do this all the time, but riding in heavy rain will make you need to check cable lubrication more often.


Finding Geometry Information for Vintage Frames I'm thinking about buying a vintage ('80s or '90s) frame for a 650b conversion. In my dreams I'm hoping to find a big frame (60+ cm) with long chain stays that was built for center pull or side pull brakes. I figure this means I want to go looking for old geometry charts and/or catalogs. I know about some sites, such as Vintage Trek and The Headbadge (although I can't find much geometry information there) – are there others?

For a 650B conversion, the length of the chainstay is mostly irrelevant, because a fat 650Bx42 tire has about the same outer diameter as a 700Cx25 racing tire -- so it's rare to have too short of chainstays for a 650b conversion. And most of the appeal of a 650b conversion is that you can get the handling and feel of a compact sporty bike with the softer ride of wide tires, so I wouldn't discount short chainstays from your search.

The most important thing to look at it whether the bike will physically fit the wide tires, and that comes down to the width between the chainstays and the width between the fork blades. These clearances are hardly ever given on geometry sheets, so you'll either have to take a look at the bike in person, or see photos showing how much clearance there is between the existing tires and the fork and chainstays. Remember that the widest point of a 650b tire is at a smaller radius than the widest point of a 700c tire, so a frame may have more clearance for 650b tires than it looks like.

The other thing to look at is how much reach your brakes will need. That's determined by the distance from the axle to the rear brake bridge in back, or from the axle to the hole in the fork crown in front. You want it long enough to clear the tire (+ fender if you're using fenders) but longer will just lead to spongy braking. If the bike you're looking at already uses 50+mm of reach to reach a 700c rim, it's longer than ideal.

The fastest and most reliable way to measure is just to try putting the wheels in the frame. If I were thinking of building a 650b conversion, I'd start by getting a 650b wheelset and tires and bring it with me while checking out craigslist frames.


Why are my front suspension forks so stiff? I recently bought a Silverback Stride 29 MD and the forks it came with were the SR Suntour XCE 28. From Day 1 of riding the bike, I noticed that the forks were extremely stiff and I had to exert a lot of energy just to compress the forks. The advertised travel for the forks was 100 mm, however, the forks do not even travel half of the advertised distance. I tried messing around with the preload adjusters but that didn't do much. The forks also do not "Sag" when I sit on the bike but I'm not sure whether "sag" only applies to air forks.
In conclusion, the issue is that the forks feel very stiff and require a lot of energy to compress and do not travel even half the advertised travel distance.
(PS. I weigh 52 kgs if that's any help).

Weighing 52 kg, you are at the lightest end of what might be expected for an adult rider, so you will need the spring to be tuned accordingly. A coil spring has a narrower range of adjustment than an air spring, so if you are too light for the spring, it will not compress enough to be very useful. A lighter spring would be needed.
Reading the generic SR Suntour service manual, it states that your fork is shipped with a medium spring and, aside from tuning the preload:

Two additional spring hardnesses are available for SR SUNTOUR suspension forks - softer and harder than the standard coil spring.

There are three springs available then, to suit riders of different weights, at 52 kg you are too light for the standard spring and would be better served by having a softer spring installed. There are customer service numbers in the service manual too, they could guide you in sourcing a spring as they will be fairly uncommon.
It wouldn't be too difficult for your local bike shop to do the work once the part is sourced, however this raises the question of value. How well will the amended fork perform for the money, and for how long? You might consider putting the money (parts and labour) towards saving for an upgraded fork with an air spring which can be tuned much more precisely and easily; the service manual does give the specs for their air forks for rider weights under 55 kg, so this should not be difficult.


My left STI shifter has 5 positions for a double crankset? I'm in the process of installing my Shimano Tiagra left shifter for the front derailleur on my double crank and I'm a bit confused, the indicator shows it has 5 positions for a crank with only 2 chainrings (double), when using common sense says it should only have 3.

http://www.ebay.ca/itm/Shimano-Tiagra-2x9-STI-shifter-brake-levers-/300924155393?pt=US_Shifters&hash=item46107a3601

Depressing the large lever one click from the inner ring should put the front derailleur into the trim position, and depressing the large lever a full two click puts the chain onto the outer ring. Shouldn't that be it?

As @Pete said in the comments, front derailleur shifting needs a partial-shift positions. That stops the chain rubbing on the front derailleur as it moves across the cogs at the back of the bike. As you shift across the chain bends coming off the chainring and the path it takes through the front derailleur changes.

So normally there will be an extra part-shift on each gear for a double chainring (four positions) and the middle of a triple has one each side for a total of seven. Five doesn't make a lot of sense, but without playing with your exact shifter it's hard to know where and how big the shifts are.


Key points to ensure that a trainer is compatible with bicycle? What should I be looking at to ensure that my bicycle and my trainer are compatible?

The current question is: I currently have a Surly Disc Trucker with 26 inch geometry, would that be compatible with the 2013 Kinetic By Kurt?

What things so I look at to ensure that a bicycle and a trainer are compatible with each other?

Generally, not much. You need to look at the manufacturer's wheel size ratings and the hub widths allowed, along with the type of the axle (e.g. if you have a maxle, you'll need a special replacement maxle). If you're still not sure, contact the manufacturer.

If you have a standard width hub (130 to 135 mm, which you have), and 26 or 700c wheels (which you have) and a standard quick release hub (which you have), you're pretty much good to go with nearly all trainers on the market.

Kurt Kinetic has a page describing their compatibility here. If you're still not sure, either go to your LBS and try one, or contact Kurt Kinetic themselves.


How can I repair carbon damage near my bottom bracket? I have had a few gnarly chain-drops that ate at my Open U.P. carbon frame. I thought I just had some chips in the carbon, but today I removed my crank for a full bike clean and realized that the carbon in the area around my bottom bracket is quite damaged. I should note, however, that the carbon that holds the bottom bracket is not damaged. The pictures below give a pretty good idea of what I am talking about.

I am wondering how I can go about repairing the carbon on my bike. I would like to do everything I can to restore the frame as much as possible. Is there some sort of carbon wrap I can get at Home Depot or something to fix this? Any tips, product suggestions, and more are greatly appreciated!

Most of that damage is through the paint, but there are obviously some gouges in the surface of the carbon fiber composite itself. I think if you want to be sure that a repair is good you will have to consult a professional CFC repair shop. Chances are they can sand off the paint, smooth the area and lay a patch over the damage.


Modifications and changes to 2011 Specialized BigHit, anyone done these? I am looking to go from 36 tooth front ring to 32 or smaller.., possibly 30. The 2011 BigHit comes with 36 tooth front ring and medium cage rear derailleur stock.  Has anyone made this change?  Will a change to long cage be necessary for 32 tooth front?

Also looking at putting in a 8.5 Fox air Ava shock for rear to get weight down..  bad idea?  I'm pretty old so a lot of air time is not in my resume but I do like hitting some speed in downhill.

I made the rims tubless with gorilla tape and slime/latex sauce mixture, but I don't think that saved too much weight. The BigHit is 40lbs on the nose now and would like to get it to 36lbs if possible.

Suggestions or remedies you have done would be helpful. Thanks, Henry

Just looking at some pictures of the Specialized Big Hit I believe it’s a single front ring setup.

You can easily swap the ring out for a smaller one down to the minimum supported by the BCD (bolt center diameter) of your crank.

You do not need a different derailleur cage but you may need to shorten the chain.


Strategies against getting blinded by oncoming cars When I ride on a bike path alongside an unlit road in the dark, I find myself blinded by the lights of oncoming cars, even when their lights are dimmed.  This is even more true if the bike path is on the left side of the road.  Currently, I mitigate this by holding one hand in front of the lights of the oncoming cars, but I wonder if there are superior strategies.  The military tend to use bright flashing lights as one weapon to blind their adversaries, so I expect they have also developed defensive strategies against such blinding.  How can I prevent being blinded by the (dimmed!) lights of opposing cars?

Example of bike path.  It's much worse in sections without a rail.

Also, you can avoid looking directly at the headlights.  Look slight off to the side, and maybe downwards a bit.  I'd probably look at the edge of the path the farthest from the road.  That way, you'll see things on the path, without your eyes looking directly into the lights of the car.

You'll still be able to see the path just fine.


Should I buy a new bike rack if my current one has been bent? I recently bought a bike rack from a well-trusted store to fit onto my schwinn circuit bike. Just today, however, I had accidentally bent the bike rack. It wasn't horribly disfigured but it was lopsided to the right to the point that its left stand was pushing up against the rear wheel. I took it to a local shop and the person there, who did manage to reposition the rack to its normal place, recommended I buy a new one, saying it is practically dead.  Therefore, I headed to the bike shop where I actually bought the rack and explained the situation. Upon their own inspection, however, they told me everything seemed okay and that as long as no part of the accessory was actually broken and only bent, then it wouldn't be necessary to buy a new one. I myself don't see any faults with bike rack, although I am somewhat of a novice when it comes to the biking scene and have no knowledge of repairing bikes. Should I keep the bike rack and save the money or should I buy a new one?

Without entering too much in material science, when a metal is permanently deformed it is because it has worked out of its elastic region and has gone into its plastic region.

This highly reduce the ability of that part to absorb energy, which is highly desirable in all the impacts.

Though somebody may have straightened it back, it can always happen that as soon as hit a bump or have a sudden load on your rack, it will bend again, with obvious consequences on your stability.


21 speed front gears go 1 to 2 to 3 and 3 to 1, but not 3 to 2 My front gears can move up just fine, but to go from 3 to 2 I have to go 3 all the way down to 1 then up to 2 for the chain to engage. Doesn't even seem to try on 3 to 2.

This is often caused by either too much friction in the derailleur cables or the derailleur being sticky because they weren't lubricated. The derailleur is trying to pull itself down from 3 to 2 but isn't strong enough until you change to 1, which is when there's enough tension to bring it all the way down to 1.

You have to either reduce the friction in the spring or in the cable.

Clean your derailleur with a degreaser and relube with a good oil.
Then try to lubricate your cables (unless you have teflon inner cables, which are only found on more expensive / newer bikes) with a dry graphite or teflon lube.
If that doesn't work, I'd replace your front derailleur cables. The cable housing and inner  is about 10-15 eurodollars and you might be able to do it yourself. The only special tools you need are hex wrenches, Allen keys, or a screwdriver for the derailleur, cable cutter for the inner derailleur cable, and neednose pliers to crimp the cable ferrule.

Or you can ask your shop to do it. Should be only 0.5 hours labor.


shimano CS-5600 compatible rear hub and freehub body What rear hubs and/or freehub bodies are compatible with a Shimano 105 5600 10-speed 12-25T cassette?

Assuming that you have a rim-braked road-bike, any rear hub that is Shimano 10/11 speed compatible will take your cassette and all other 10-speed Shimano road cassettes.

Just be aware that you need a 1.85mm spacer that goes on a freehub 11-speed body before you put on the cassette. Without the spacer the 10s cassette will move sideways.


How to brake without falling during wet weather? A couple of days ago I fell off my bike. I was on a wet, steep downhill, asphalted road with a lot of curves. I didn't expect neither the weather, nor the 15+ km downhill route. I was always reducing my speed to 9-10 kph before taking a turn. However, just after a taking a turn and before another curve, when I pressed the rear brake lever, the wheel stopped turning immediately, despite the slight pressure, and started to slide. Worse, the bike didn't stop, it started to accelerate. I pressed the front brake lever, slowly initially, but since the bike was still accelerating, I pressed more was thrown off. Never mind the damage; I got off with minor injuries, the bike as well. This could have been due to my being careful to begin with, but not enough, apparently, so my question is how can I be better prepared in the future? And what might have caused the tyre to slide? The road was wet and with minor holes and bumps, sure, but I had gone through similar terrain seconds ago and I could brake just fine. And I'm sure I didn't press the lever way too hard than perceived. Also, there wasn't any wet sand. None that I could see anyway.

In hindsight, there are a few things that came to my mind. I'm not entirely sure about any of them, however, since I have just recently started to cycle since my childhood/high school years and I just discovered that there was stuff I was missing out on back then (such as bike fitting and geometry).

The saddle could've been lowered. I normally ride so that my knees
bend at a 25-30 degrees at the pedals' lowest position. I assume
lowering the saddle would've necessitated much more effort from the
front brake to throw me.
My bike is suited for XC racing. Would picking a downhill bike, with
the appropriate frame geometry, have made a difference, provided we're
talking about an asphalted road?
Should I have kept the rear or both brakes engaged constantly? At
the time, I didn't want to do this out of fear that they, being disc
brakes, would overheat and the rotor would be destroyed. The route I
was on was at least 28 km long, mostly steep downhill, save for the
last 10 km or so, which were a rather pleasant, slight descent.

when I pressed the rear brake lever, the wheel stopped turning immediately, despite the slight pressure

if it locked up with only slight pressure, either your brakes lack modulation, or it had really poor traction.

The first (modulation) is generally adjustable.

The second depends on your tyres, the road surface, possibly oil/petrol/diesel spills, loose material etc. etc.

Since you don't think there was loose material, and say the traction was fine previously, an oil spill is certainly possible - look out for those rainbows on the road surface.

  Worse, the bike didn't stop, it started to accelerate

If the back wheel is locked, skidding it should still have some braking effect, so I'm inclined to view this as evidence for poor traction.

  I assume lowering the saddle would've necessitated much more effort from the front brake to throw me

Did you go over the handlebars, or just lose grip with the front wheel and crash?

If the former, which I think is what you're suggesting - lower saddle might help on steep downhills, but generally you need to brace yourself down & backwards with your arms. The goal is to stop yourself sliding forward relative to the bike as it slows down, and also to reduce the angular moment about the front axle by keeping your weight low.

Interestingly, this does suggest there was no traction problem with your front wheel, so something happened to impair traction at the back only.

  My bike is suited for XC racing

Does that mean it has knobbly tyres? More contact area is generally better on asphalt, so slick or textured tyres will have better traction (and, as a bonus, generally lower rolling resistance).

  Should I have kept the rear or both brakes engaged constantly

I'd usually drag the back brake to control speed on descents - to avoid overheating, don't do this continuously, but pump it and ease off to let it cool. Alternating with the front will also give the back brake a chance to cool - but note the front brake affects steering more, so definitely keep braking to the straights as much as possible.


Why do front and rear wheel hubs have different sized ball bearings? Conventional front wheel cup and cone bearings have 10x 3/16" ball bearings per side, whereas the rear wheel has 9x 1/4" ball bearings per side.

Manufacturers have been on a continuous quest over time, to simplify bikes in terms of ease of assembly, and of inventory.  To the point putting retainer rings on ball bearings makes 9 items into one on the rear, and saves one or two balls.  This will also speed assembly.

Seven 1/4" balls in a retainer do the same job as Eight or Nine balls outside a retainer.

I'm guessing that the smaller the bearing, the more will fit in the equivalent sized race, so the number and size are directly linked.

So why have a different size of bearing for the front vs the back?

Is the weight load on the rear is enough to require fewer and larger bearings?

Or the lack of weight on the front wheel is sufficiently different to allow smaller, possibly cheaper ball bearings?

Is there a rationale?  Or is it another of those "this is how its always been"

This has puzzled me for a while, SE lacks any relevant question, and even searching the web comes up with no good answers.

First of all, the standard shimano cup and cone bearing size is not necessary, take their own XTR FH-M975, this had 3/16th bearings in a rear hub.

One thing I considered just now was that an MTB will sometimes be on only one of the hubs, so it is unlikely that there are issues to do with damaging either bearing size in this way.

What is left is the typical average load distribution; bearing size and load are both factors in bearing life, as such my overall conclusion is actually that this is a bearing life issue more than anything else, they're simply attempting to obtain the same life from the front and rear. Even as bearings improve this provides a valid reason to keep the size disparity to increase rear bearing life.

http://www.skf.com/us/products/bearings-units-housings/principles/bearing-selection-process/bearing-size/size-selection-based-on-rating-life/index.html

Outside of cup and cone one can take the Hope Pro2 Evo for example, the front takes 20x32x7 while the rear takes 17x30x7, the bearings in both are the same size, but the rear has less of them. I'm guessing that the front only takes more bearings to increase the cartridge radius to accomodate larger axel standards. It's worth noting there are another 3 bearings in the freewheel of the hub, I'm unsure how this affects things, but then there are also bearings in the shimano freehub. Edit: Anecdotally the rear bearings on my pro2 evo needed replacing sooner than the front.

The load really is significantly different:

Lennard Zinn on measuring rear and front load, and "don't be surprised if it's 70/30"

http://www.velonews.com/2015/01/bikes-and-tech/technical-faq/technical-faq-weight-distribution-compatibility_357312

For otherwise identical bearings the load it can take increases with size.

https://www.bearingworks.com/bearing-sizes/

The above is not ideal as it deals with 6000 series cartridge bearings, where the number of bearings varies as well as their size, but it shows clearly that the the load rating increases with size of bearing (when the width increases).

If you want to get more in depth with regard to anything and everything bearing related then check out and explore starting from

http://www.skf.com/us/products/bearings-units-housings/principles/bearing-selection-process/bearing-size/index.html

http://www.nmbtc.com/bearings/engineering/load-life/

EDIT:
My final thought is that cup and cone are the staple of cheap hubs, any change would presumably increase costs (at least initially) and go against standard expectations for bearing sizes, any increase in cost to a manufacturer is passed on to the consumer, in the case of budget hubs there's really no advantage to the consumer for the increased cost, I mean, they work, they work very well for a very long time when maintained, and surprisingly well for surprisingly long even when they're not! Even if you could show this or that improvement in weight or rolling in an optimised hub, would this actually translate to more profit? I doubt it very much. So manufactures just keep things the way they've been, because there's no advantage to be had for the company by changing it.

Also consider the complaints from people that you messed with bearing sizes, no doubt there will be enough people who will put the wrong bearings into the new hub, who will then proceed complain that your company sucks! There are countless examples of technically sub-optimal solutions everywhere you look, many of them are however optimal for profits.

I strongly believe (but can't prove) that a simple philosophy that "both wheels should last equally long" was the main driving force behind the initial decision.


Shimano Steps E600 trip meter Help please - I don't know how to enter settings on my Shimano Steps E600 cycle computer or how to reset trip meter after journey.

The manual  says on page 24

THE SETTING MENU CANNOT BE LAUNCHED WHILE RIDING THE BICYCLE:  The product is designed in such a way that the settings menu cannot be launched if it detects that the bicycle is being ridden. This is not a sign of an abnormality.  Answer: Stop the bicycle to adjust the settings.

Resetting the trip meter is on page 27 of the manual.  Problem with this is its the bike's odometer, not a trip meter for each ride.  So by resetting this you have no idea how far your bike has gone in its life.  This is valuable information for servicing intervals.  It would be like clearing the odometer for a car.


Park Tool TS-2 Truing Stand Upright Adjustment Knob I just bought a used TS-2 truing stand that was in storage for years. Used one time, according to the previous owner. I cannot get the Upright Adjustment Knob to move the uprights in or out. The black plastic handle has a lock nut to lock it onto the shaft but when the handle is locked in place I can't move it clockwise at all and when I try to move it counter-clockwise it loosens the handle from the locknut and the handle unscrews. Any tips on how to work this? Thank you in advance.

RoboKaren was probably right about frozen grease. I decided to install a rebuild kit that is made for this stand. Started taking it apart and got to the step that says to turn shaft to remove it. It still wouldn't turn so I put a long wrench on it and it turned. So perhaps I was being too gentle with it before. At any rate, I'm going to finish the upgrade even though the original parts are probably fine, as this stand was hardly used. Park claims the upgrade will be better anyway. Thank you RoboKaren.


Does riding bicycles reduce sperm count? I have heard this many times before. Is there scientific evidence for this fact? Or have any of you come across this in your lives?

There are studies that link cycling to Erectile Dysfunction. A quick Google will point you toward further reading. I'm afraid I don't know what the link is (or indeed whether there is a link) between ED and sperm count.

The link between cycling an ED is because of pressure exerted on parts of your body while riding. You therefore won't find it surprising to learn that people will suggest one saddle design over another, with this in mind. How much substance there is in any of this......it's all subjective.

I think that, in general, though, the health benefits of cycling (helping to prevent e.g. heart disease) are considered to outweigh the risks. ED, for example, is in most cases temporary and reversible.


What is special about 1x11 - why not just big cassette and single front ring? I currently ride a single speed belt Soma Wolverine with road bars, hydraulic disc brakes and I love it. Only trouble is my knees are telling me I need some lower gears especially up the hills. That's 55:22, 175mm crank, 700c-28 wheels - About 69 gear inches? Go to a 50-tooth front ring sure, but then I would go spin out even sooner down hills. I want to keep it simple, I have tried Alfine 11 and did not like it (leaks make the clean belt drive dirty, big heavy hub on the back wheel), do not have the money for Rohloff. Looks like a 1x11 setup is for me.

SRAM has 1x11 group sets that will do the trick. But SRAM is uncommon - never seen it on my bike trail in Melbourne - and discounts are far less common.

With other big two, fair chance of picking up discounts on random 11-speed stuff. So question is - what makes a 1x11 groupset special? Is there any reason not to pick up a heavily discounted Ultegra spider, a  third-party 42T ring, a Deore XT 11-42 cassette, matching XT derailleur and matching brakes/shift levers?

The issue could be that moving from one extreme to another the chainlink is just a whole lot wider and the chainline way more bent than it might be designed for. Do 1x11 groupsets have any design features to deal with this? Do you need a chain designed to flex to allow for this worse chainline? I have no issues building wheels/changing bottom brackets to make this work.

Update: 1x11 is not so hard! Here's what worked for me.

Brakes: This is the driver for a lot of decisions. Wanted drop bars, hydraulic brakes and lever shifting. All brands have options but I chose Shimano Dura Ace levers and calipers, based on available deals. Also as mentioned much easier to build the whole kit with compatible, discounted parts. Unfortunately the Dura Ace calipers will not work on my IS-mount frame because there just is NO flat<->IS adapter as there is for many other combinations. They're put away for the next frame.

Crankset: Dura Ace FC-R9100. Again, the big discount tempted me and it's really pretty - functionally probably no better than Ultegra. And I can sell the two rings it came with.

Front ring: Wolf Tooth 110 BCD Asymmetric 4-Bolt 38T, with their special chainring bolts - very nice, hex key on both sides! "Rides of Japan" on youtube showed a 1x11 conversion with this ring and Di2 system. Teeth are thick/thin alternating. You do have to file away a small part of one mount to fit it on modern Shimano cranks but is a small job, Wolf Tooth even explain this and the video shows it too.

Chain: SRAM PC1170. Comes with a special one-time link that makes joining pretty easy.

Rear cassette: SRAM PG1170 11-36 - very wide range, mid-price. I think the 42T would not work on the GS derailleur.

Rear derailleur: Shimano Ultegra RD-RX800. I worried about this because Shimano say this derailleur is good for a maximum 34 teeth but it handles 36 OK with plenty of adjustment left. Nicely made! This is the "GS" medium cage model with a clutch, so with the clutch engaged it will apply extra tension and stop the chain from slapping around over bumps.

Downshift cable hanger: A Wolverine frame has downtube shifter braze-ons. I needed to find one right-side cable hanger to make the gearshift cable run, or else I would have needed a full-length cable sheath.

Brakes: Going to use some Shimano M675 SLX calipers Was going to use some M675 SLX callipers but bleeding them I found one is leaking from the cracked ceramic piston and spares are not sold. Used for maybe 6 months commuting. Disappointing quality again, Shimano. Will now be using TRP Hylex (original) calipers with the with the Dura Ace levers. Have found people in forums successfully mixing Shimano calipers with Hylex levers so no problems anticipated.

Outcome: 11 gears between 27-91 inches. Both higher and lower than I had. Shifting is smooth.

SRAM have emphasized the 1x configuration, but 1x systems can be built from Shimano components too.

You are right that a 1x system is pretty much a wide ratio cassette and a single front ring. Double-wide chainrings are commonly used to help chain retention as there is no front derailleur cage to guide the chain. Clutch derailleurs are also used to tame chain slap on rougher trails encountered when gravel riding.

You can use a double crankset with a single ring on it, but it's a hack and as you say you will have cross-chaining problems. Dedicated 1x cranks align the ring with the middle of the cassette so the chain deflection is minimized.

You will not be able to use a XT MTB derailleur with a road drop bar shifter. Shimano MTB and road 11 speed use different derailleur actuation ratios (see here) so MTB derailleurs and road shifters are incompatible. The largest cassette that Shimano long cage road derailleurs can take is 11-34, but, if you are coming from single speed that is going to feel like a huge ratio range.


Material to make patches to fix Crosso / Ortlieb style waterproof panniers? I've got some panniers to fix. I've bought some impact adhesive and I am working out which material to buy for the patches - will PVC ok ? or polyurethane or something else?
Has to be waterproof and strong and preferable available in yellow!

You could try an air bed repair kit?
The patches are tough, the bond is flexible and air tight.


What make and model is this bicycle? can you tell me what make and model this bicycle is?  And maybe tell me what year and how much it may be worth?

I had one just like it many years ago. Not a good collectible, and not worth much. It's an old Murray.


Diagnosing and correcting hop on carbon wheel NOTE - please read update below and all comments.

I have a Mavic Cosmic carbon wheel which is perfectly true, but it has some vertical hop (3-4 mm). I thought at first that it was out of round, but deep carbon rims are very strong and rigid, and I don't see how it's possible for it to bend.

I did a test to check the roundness of the wheel - I measured the radius at different points around the wheel (from the hub to the outside of the rim). It was 306 mm all around. So the wheel is round, right?

I took the quick-release axle out and rolled it along a flat surface - I noticed that it is slightly bent, maybe 1 mm max deviation. I guess this is at least partially contributing to the hop, but I don't think it fully explains it. I will replace the axle - hopefully that corrects the issue, but if not, what else could be contributing to it?

UPDATE

I've replaced the quick-release skewer. The wheel still hops, so at least it's eliminated that possibility.

Here's a video showing the hop. https://imgur.com/a/icMfN7q

I've also noticed there is a slight raised area at the edge of the wheel at one point. This is on both sides, like the wheel edge is slightly "flared" at that point. This is very slight but enough to alter the braking force at that point - I can feel pulsing through the brakes as the friction increases at this point. Looking at the wheel rotating again, it seems to pull in sharply at this point. So it's like the opposite of hop - what's that, dip? This causes the excessive rubbing and you can see the brake marks below:

By 'hop' I assume you mean radial run-out (as opposed to lateral run-out).

A bent axle will have no effect on the rim running radially true or not, because the hub rotates around the static axle. A slightly bent quick release shaft will just conform to the bore through the axle and have no effect.

A rim can be perfectly circular but still have radial run-out - if the hub axis is not at the center of the circle. That may be what is going on here. In any case the solution is to have the wheel re-trued.


Swapping wheels and cassettes with Shimano GRX 600/800 I am in the market for a gravel bike. I plan on getting a second set of wheels for road rides. This bike will most likely have Shimano GRX 600 or 800 2x and an 11-34 cassette. Assuming the rear derailleur is set up properly for that cassette, I'm curious if there any issues having an 11-28 cassette on the road wheels to get closer ratios:

Would any derailleur adjustment be needed when swapping?
Would a chain sized for the larger cassette work with the smaller one?
What is the maximum difference that would likely operate satisfactorily?

Most of the trails out here are quite rough and steep, so there isn't an ideal tire or gearing for both road and dirt rides.

My experience with swapping wheels is disappointing.
I had to adjust the derailleur (limit screws, cable tension) and rim brakes (due to slight difference in rim width and dish) every time I swapped wheels. Maybe if you have exactly the same hub and rims on both wheels it will work better. I think my derailleur adjustments were necessary because the cassette position was ever so slightly different between the two hubs.
The longer chain should work fine on the 11–28 cassette. After all the small-small combination is the same, so your rear derailleur should be able to tension it enough.


Hydraulic disc brake clicks once when I pull the brake lever and the braking force is very bad I have a brand new Trek Marlin 5 (1-2 months old) with hydraulic disc brakes and the rear brake doesn’t work well and when I pull the brake lever, it clicks once somewhere in the frame (cables inner routed).

First, don't ride the bike if one of the brakes is not working properly. Not working well can change to not working at all and put you in a dangerous situation.
Take the bike back to the store where you bought it, a 2 month old bike with a major brake problem should be fixed under warranty. In any case if you do not have experience diagnosing and repairing hydraulic brakes you should have a professional address this problem.
The problem is likely that the rear brake has lost hydraulic fluid, or perhaps a seal has broken in the lever or caliper.


What sort of bicycle helmet gives me better speed? I am working to improve my segment times on Strava riding 10km to/from work.

My average speed is 32 kmph, and over short segments (1km) I can set avg speed 44 kmph / max 49.

Over the last year I have invested in a new bike and bike shoes, and now I leave a week's supply of clothes in advance in my work locker so that I can ride without a backpack - all of these improved my strava times.

Now, I am wondering if my "standard" bike helmet is a source of wind resistance that can be improved.

Is there a sort of bike helmet that is more aerodynamic? For example, a tempo helmet, or a helmet that doesn't have the "cooling" holes?

What features and considerations should I look for when buying a helmet, given I am most interested in riding faster.

Cheers
Viking Steve.

I think this is kind of a non-question. You want the helmet that rides the fastest? For anything "fastest", either components or kit, just look at what the professional riders are using.

This seems to imply that you either wear a regular-design lid (albeit one which is very light, very ventilated, and probably very expensive). Or, you go for a time-trial helmet.

I know some team helmets used to be made by Giro (as I bought one, Ionos springs to mind, but I'n not 100%). This was a couple of years ago, I would assume it is still the case. As for the exact model, just look at the top of the range. At the start of this year's Tour de France, a bike shop I follow on Facebook ran a competition to win a Team Sky helmet - manufactured by Kask. So there's two manufacturers to give you a start.

As regards TT helmets, when I watch time trials a lot of the riders seem to wear Specialized lids, not just the Specialized team. So they might be a good place to start looking.

I presume you realise (and accept) that for this kind of top-notch quality, you will pay.


Not finding the right tension for my threadless headset I recently installed a new fork on a bike I'm building up. I find that before I get the preload tension correct on the top cap to remove knocking, a squeaking sound starts emanating from the steer tube area when I turn the handlebars.

I am going to disassemble the whole stack tomorrow and make sure that everything is on in the right order and that nothing that shouldn't be there is present.

FYI I put the crown race on and installed all the bits of the headset and everything looks fine. Does anyone have any experience in what might be causing such a noise?

If it makes any difference, I'm using a carbon steer tube and a "problem solvers" expansion plug.

I figured out what was causing the problem. I had used the compression ring in the place of the crown race. I did this because I lost the crown race and the compression ring looks similar.

FYI crown races for threadless headsets aren't standard, if you need to replace one you have to get one that matches your make and model.


What makes a durable and dependable commuter bicycle? I ride between 150 - 180 Km per week (depending on route) and all of it is on bike path or road. I have been riding a Norco Alloy Threshold Sora. It has not been a fun experience, because within a year I have had both wheels replaced (lost too many spokes), oh my riding weight is close to 90 Kg. And recently the left pedal crank sheared off...(still within a year of purchase).
I am just wondering if I am expecting too much from this bike as a daily commuter?
Whether I should be investing in something like a Surly etc?
Love to get some advice from you guys.

You probably have too high expectation. I imagine very few bikes with Sora quality components would be ridden that far in 10 years, let alone 1.

With any bike the amount of regular maintenance is far more important to longevity than any other aspect. At those distances, a weekly maintenance check on the normal stuff - tire pressures, cleaning and shifting, brakes etc needs to also include tires, wheels and spoke tension, chain wear and bearings (Headset, BB) etc.

Buying something like a Surly would be a good choice, any brand renowned for reliably rather than performance (Clydesdale vs thoroughbred) would be a good choice. Most main stream brands have a model that is aimed to be robust than their out and out racers, so its more matter of choosing the right frame, then the right component level.

At those distances, 105 would be a good level to aim for. Too high spec components are trading durability for weight. Low spec will wear out too quickly.

Wheels and spokes fail from poor initial build quality and lack of maintenance - a Sora quality bike would have come with machine built wheels so chances are the problems started before it left the factory. Upgraded wheels are better to the point they are being made lighter rather than stronger.  if you really want them to last, go for 36 spoke wheels, and get them tuned by a good wheel builder before riding, and after a few hundred kilometers. Wheel made for gravel or touring bikes will last longer than wheels made for speed.

Crank failure is most likely due to something other than high use - accident damage or manufacturing fault. Cranks do have a very high margin of safety as a failure is catastrophic - More expensive cranks are usually stiffer and lighter, and if anything, weaker rather than stronger.


Resetting unknown E-Tube Passkey I just bought an e-bike from Wiggle's demo fleet and am having problems with the electronics. I think I need to do a firmware update but I can't get into the E-tube app which allows me to configure the settings.

I tried using a passkey of "000000" to access the setting, but it didn't work and I don't know any other default passkey to try.

Is there a way to reset the passkey without knowing the current one?

Is there a recommended way to contact a Shimano for product support?

You can reset the Wireless passkey - even if you don't know the current one - by connecting your bike to a windows computer/laptop using the charger.

Download e-tube for windows at https://e-tubeproject.shimano.com

Then do this:

Connect the bike to your computer using the charger and Junction A
Open the e-Tube windows app
Make a connection by clicking "connection check"
Click "Bluetooth LE settings"
Set a new passkey

You can now use the passkey you just set to connect to your bike using BluetoothLE/ANT+. The Passkey is required for wireless connections only.

Also: if you really want to update firmware then I recommend using a computer (over USB) rather than the mobile app. It a bit safer. You can update using the mobile app, of course.. but as far as I'm concerned the mobile app's main feature is changing settings easily (out on the road).

More info:

resetting your passkey: https://di2center.com/2019/05/05/change-your-di2-wireless-passkey-using-the-e-tube-app-or-windows-computer/  (2nd half of page)
connecting to computer https://di2center.com/2019/04/22/how-to-connect-your-di2-system-to-your-computer/

(disclaimer: my website ;). If you're having more problems and can't figure things out don't hesitate to ask)


Crankarm hitting frame - BB-R60 with GRX 1x11 Hybrid - Gravel conversion Hope someone can help
I'm converting a hybrid frame to a gravel/adventure bike and am using the GRX 1x11 rx600 cranks. I've got myself a BBR60 Ultegra bottom bracket but the left-hand (non-drive side) crank arm hits my bike frame as it rotates. The amount it clips it by is 1 or 2 mm at most, so very annoying!
Question is can you get spacers for this bottom bracket, or would it be worth returning it and getting another one?
Thanks

If it's a steel frame, then adding indentation on the left side is a solution, albeit an advanced one that needs to be done with care. A good way to do it at home is use a piece of wood and a rasp/file to create a support form for the inside of the chainstay, tape that to one vise jaw, tape a socket lengthwise to the other vise jaw, and squish. The way they do it at factories is not particularly any more sophisticated. A good rule of thumb type minimum gap to avoid rub under load is 3mm, so in other words you're doing 2mm to eliminate the interference and then another 3 to accomodate flex. Measure the frame OLD beforehand and then if it changes, align the frame afterward with a 2x4 and string. Standard caution that yes you can destroy the bike doing this kind of thing.
If it's not a steel frame there is no solution.
There are no spacer tricks you can play with Shimano road cranks because you can't compromise the left side spline engagement by any amount, and certainly not by the amount you would need here to both eliminate the interference and then create the aforementioned gap. Not safe, risks ruining the cranks and/or having the arm fall off etc. The BB is intended to use without any spacers, so there is no swapping or adding spacers to offset it. (In other words, yes you could create clearance by adding spacers under the left side cup or on the spindle itself, but there will be inadequate contact surface between the spindle and the crank with any such solution.)


Where to buy a used bicycle in Germany? I would like to buy a cheap bicycle in Germany. Is there any place to search for a used bicycle (like a market or an internet site)? I don't speak German so places where people might speak English are preferred.

eBay:

http://kleinanzeigen.ebay.de/anzeigen/s-fahrrad/k0

Open in Chrome and use 'Google Translate'. 'Fahrrad' is your keyword.

P.S. Most German people speak better English than some English people do!!!


Gear mis-adjustment. Loss of gears How do I adjust the rear gears of a bike that will not change to higher gears?
It is stuck in lower two or three gears.

By higher gears I assume you mean smaller cogs on the back, which are higher ratio gears.  Usually your derailleur won't go there it's because of cable friction, although you could have a bent derailleur or derailleur tab.

If you remove the cable from the derailleur it should drop down into these gears.  If not it's probably due to a bent hanger or derailleur.  If you can physically shift the derailleur to all the cogs with your hand on the derailleur then you should change the cable.  I'm assuming that your gears used to all work and that you haven't messed with the limit screws.

A good way to check your limit screws is with the cable detached from the derailleur and then push the derailleur with your hand as far inside as it can and let it drop as far as it will. This completely eliminates cable friction.

With the cable attached to the rear derailleur I like to shift the derailleur into the smallest gear in the back and then grab the cable that goes to it as it runs down the downtube and pull it until the derailleur shifts to the biggest rear gear, this is the best way test for the L limit screw and it prestretches the cable, so won't have to adjust it as soon.  I learned this from a Mavic neutral support mechanic.


How to measure which sized bicycle can a toddler ride? The child is female and is of 2.8 years old.

We have a choice between 12 inch, and a 14 inch cycle. Don't have any cycle shops around. Will be purchasing this online.

I don't know what 14 inch  stands for, but as you can see there is a size difference between the following 12 inch cycle and the other 16 inch one.

Cycle is supposed to have supporting wheel.

http://www.herocycles.com/kids-zone/fruity-12t?sort=p.price&order=ASC#.VrmyXahX5J8

http://www.herocycles.com/kids-zone/blaze?sort=p.price&order=ASC#.VrmyOKhX5J8

How to measure which sized bicycle can a toddler ride?

I found A definitive guide to sizing a child's bike and Children: Choosing A Bike / Buying a Bike using a search for "size child's bike".

Bike fit for young kids, especially kids who are about to learn to ride, is quite different than for older kids and adults. Rather than being about comfort while riding, it's more about lack of pain when falling off.

The two things I think matter are stand-over height which also matters for adults, and how high your child can lift their feet without falling over.

Stand-over height is basically how high their crotch is when they're standing up. Normally for adults we'd say "a little daylight between crotch and top tube of bike", but for kids I feel at least 5cm is needed, and ideally they'll be able to lift themselves off the bike seat with both feet on the ground. This is about feeling safe on a new toy rather than having an efficient riding position for longer distances.
Foot-lifting height is because kids rarely start by doing the "swing leg over back of seat" mount that adult men do, they lift their foot over the top tube of the bike. Or they try to, and fall over if it's too high.

Other major considerations are budget and community, because they determine how long you're likely to keep the bike before swapping to a bigger one. If this is your one bike until your child is riding to school then training wheels will probably be better than a balance bike. A 5 year old can ride a bike that used to have training wheels, where a big kid on a little balance bike won't work. But if you're in a position to buy a balance bike and a bigger bike, the balance bike will work better. Likewise, if you can pass a balance bike around friends or family and get a second hand bike the same way, it's much cheaper and easier to do that than buy anything.

This was superseded in many ways by a later question about balance bikes but it's worth answering anyway.


Crankset replacement for TERN Verge D9 (9 gear folding bike) I need assistance with replacing the crankset on my Tern Verge D9 folding bike.
The pedals threads are ruined - presumably due to cross threading.
Nothing immediate comes from googling - but I am looking for assisitance as to a replacement.
The info engraved on the drive-side crank says "PROWHEEL Forged Ounce 170"
Any info you can give would be greatly appreciated!

The first thing I'd do is contact Tern and see if they can supply a replacement. That's the easier way to make sure you get a compatible crank.
I don't think it's possible to buy Prowheel components directly (at least they didn't show up in a couple of online bike retailers I tried) so you need to find a compatible replacement. From the Tern Verge D9 web page we can see that the crank is single ring, 53 teeth and fits on a cartridge type bottom bracket - presumably with a square taper axle-crank interface. The info written on the crank tells us it has 170mm crank arms (measured crank spindle center to pedal spindle center). The tooth count and crank arm length you can of course verify.
You can search for folding bike cranks that match these specs. An alternative is to look for 'track cranks' (used on single speed velodrome track bikes). These may be easier to find but typically have smaller chainrings, but you can also find replacement chainrings that match the bolt pattern and circle diameter.
The complication is that each crank model requires a specific bottom bracket axle length to get a specific chainline - how far away from the center line the bike frame the chainring is. It can be tricky to find this info for cheaper and non mainstream brand cranks. You may need to replace the bottom bracket with one with a different axle length to get the right chainline.
Special tools are required to get the crank arms off the axle tapers and to remove and install a cartridge bottom bracket from the frame. Additionally everything really need to be installed with a torque wrench to make sure bolts are tightened to proper specifications.
On that subject, threads in the crank arms can get deformed and ruined if the pedal spindles are not tightened properly. The hard steel starts to wallow around in the softer alloy crank threads. That's probably what happened to you cranks.
If you are not familiar with bike repair (presumably you are not, as you're asking here) you'll need to enlist a local bike repair shop to help you install the crank, and they will of course be able to help you source a compatible crank.


Neck pain after BG Bike Fit? I did the smart thing and went in for a bike fit 3 weeks ago.  I had some serious pain in my hands which has since been essentially resolved.  Now, in the drops and at the hoods, I get pretty wretched neck pain 4 miles in.  I stretch my traps before and during the ride but can't get any relief. I had not owned a road bike before and just started biking on a daily basis 10 - 15 miles at a time.

Is there a fit issue that still needs to be resolved or am I paying the price for weak trapezius muscles?  The pain essentially goes away by the end of the next day.

Thanks.

Go back and get fit again. You paid them, it shouldn't be painful. It might be a little uncomfortable at first, but shouldn't be as painful as it sounds. A new stem and stack height may help.


Are two different tires marked with the same dimensions (700 x 25c) the same size? Both sets of tires are from different reputable manufactures but the details are the same. ie Clinchers folding etc.

I recently changed my tires on a road bike, the clearance on top section of the rear seat stay was always very small with OEM wheels and tires. I would guess about 3-4mm.

I got new tires with the same specs from different manufacture and at the recommended psi the clearance from the top of the seat stay is about 1mm and I never noticed it while riding about 3k miles. But once i took it apart i noticed that the tire has been rubbing on the seat stay. I can see the paint has rubbed of slightly.

Update: picture below - hard to see because of brakes but the top of the seatstay is marked with red line and the top of the tire is marked with green line.

Wheels are true!

I'd check if the wheel was in properly and is in good condition (true) along with the tire being mounted properly on the rim.

There is some variation in tires true sizes despite being marked the same size, though half a cm would be a lot larger variation than one could reasonably expect, especially with older tires. Features like studs, knobs can also affect this. If you have reasonable clearance for a given size of tire, one should reasonably expect a similar tire from another manufacturer to also give reasonable clearance, though this is not always the case.


When should I move onto double jumps from tabletops? I do mountain biking on some of my local trails and I have started doing some tabletop jumps which I can now clear, but I am afraid of starting to try doubles. Any advice?

Thanks.

Such fear is completely normal. Eventually you'll get over it, and even though it's different for different people there are some things you can try to help you cope with that first time. Here are some approaches I've either used myself or seen with others - in the end it mostly only comes down to what CardMechanic already answered: in case you can properly jump tabletops, literally the only thing holding you back from jumping similar doubles is a mental block.

First of all, and this applies to all other steps below actually, clear it properly in your head. Imagine yourself confidently and cleanly jumping the double, in the same way you do it for the tabletop. Imagine looking down and flying over the hole in the middle. Visualize it.
Measure the tabletop, e.g. put your bike next to it and see how the length compares to your bike's length. Then go find a double with roughly the same size or smaller, put your bike next to it in the same way, and make your brain realize it's being irrational.
Get good at estimating speed needed for jumping a tabletop, find a similar double (both distance and shape of the kicker, both are important in defining what a jump feels like), and just go for it at the same speed. There's no way you won't clear it.
Have someone else jump the double and ride next to him/her to figure out the correct speed. Seeing others do it at exactly your speed will make you more confident.
Make yourself irritated, to the point you are getting a bit angry even, by riding onto the double like you are going to jump it but in the last second ride around it. Eventually alternate with jumping thea tabletop as well to tell yourself 'yeah, I can do this'. Doesn't work for everyone, but chances are after a while you start to feel a bit supid and annoyed and angry and at one point, make the click and decide to go for it.
Find an appropriate double and cover the hole with for instance a pallet. Now it's basically a tabletop. Jump it a couple of times and you'll find yourself removing the pallet in no time.
Final words: know that once you clear the double for the first time, you'll be welcomed with rushes of adrenaline, dopamine and whatnot and you'll be walking on sunshine - best feeling ever, you know you want it.

edit as requested, some info from the comments: the reason why I'm mentioning finding a double similar in shape/size/length to a tabletop you know how to jump, is that you can clear both with the same body movements and hence don't have more risk of over- or undershooting it.

Overshooting a double or tabletop is the same: if you have some amount of experience and spot your mistake early enough when in the air you'll by all means want to avoid landing front wheel first since that might end up going over the bars. Instead actively force the rear wheel down - but also not too much. Even when completely overshooting and having to land on flat that has a good chance of not resulting in a crash. And it's easier than, while in the air and possible panicking a bit, trying to aim for a landing with both wheels at the same time. Actually you can train for this to some extent: take a jump you know well, then try to land a few inches further. Then some more, and so on, and take mental notes of how it feels and what happens and how you can counter it.

For undershooting it depends on how much you undershoot. If it's only a bit, e.g. hitting the top of the landing with the rear wheel (not ideal, but unless you're really short you'll just ride away) or the front wheel (dangerous, often results in an uncontrolled 'bounce') there's no difference. If you undershoot way too much though, a tabletop will save you but on a double you'd land straight into the gap. Which can end up pretty bad. But can be avoid by not trying to advance too fast, i.e. if you can jump X easily, don't attempt a double which is X * 2. Take small incremental steps, as for any practice out there.


Can I replace steel bearings with ceramic bearings? I'm using WH-550 from Shimano, can I replace my steel bearing balls with ceramic bearing balls?

Yes, you can. You just need to get the right size of loose ceramic ball bearings as that's what shimano wheels use. They are available from various vendors, like here for instance.

You didn't ask this, but I'll answer it for you anyway: would I recommend replacing the bearings on a pair of WH-R550's with ceramic bearings? No, and neither would many others. Ceramic bearings are expensive and can end up costing nearly as much as your particular wheelset. There are better places on your bike to spend that money and get more bang for your buck. A lighter, more aerodynamic wheelset would be a great place to start.


What does "chain binding" mean? I'm reading on chain tensioning, the generic idea is that if the chain is too loose it will fall off, if it's too tight it will "bind".

I'm having an hard time understanding what "bind" means in this context. The best I could think of is that the teeth from the cog will be tight to the chain causing both teeth and chain to wear out more easily, but I couldn't find any proof.

These are the sources I was reading:

one is a question on Bicycles:

  The simple answer is, as Sheldon brown says, as tight as possible without binding.

Second is on Brown's blog:

  If the chain is too tight, the drive train will bind, perhaps only at one angle of the pedals (chainwheels are not usually perfectly concentric). It should be tight as it can be without binding.

"Chain binding" occurs when the chain is really tight around the sprockets.  No set of sprockets is perfectly round and centered (especially if worn a bit), and if the chain is tight at one spot in the rotation it likely will become too tight with another half-turn or so.  The pressure of the chain on the sprockets makes the crank more difficult to turn, or, if the sprockets are really off-centered (though likely not visibly so) the crank may lock up entirely simply because the chain isn't long enough to reach all the way around.

Even if the sprockets are perfectly uniform and centered, the friction of the chain links against the teeth will contribute to a sort of "drag", if the chain is too tight.

Note that this is different from having a "frozen link", which is a defect in the joining of an individual pair of links in the chain.


How to disassemble a Topeak JoeBlow Sport II OK... I searched everywhere, could not find  a definitive answer.

I've had the pump a few years and use it a lot on several bikes.   I like my pump and want it to last as long as possible and I'd like to clean and re-grease its innards as a preventive measure,  the o-ring specifically but I cannot get to it.... I'm afraid I'll break it

Can anyone tell me how to get the cap off without breaking it?  or is there another way?  It's a JoeBlow Sport II (the yellow one)

Thanks in advance

Well...  I tinkered carefully and was able to remove the top cap without breaking anything.

1) There are 2 small holes on the sides, right above the hose holder clip.  You must push in the tab that keeps the top cap secure using a pointy tool and turn the cap slowly clockwise. Here you see it with the tabs disengaged and showing the holes the tabs click into.

2) In the second image, you can see the tabs that hold the cap secure.

3) Then I was able to clean the the inside and clean/relube the O-ring (I used Slickoleum because  it's O-ring friendly... I use it to service my front suspension).

I think this pump is taken apart pretty much like any other cheap to midrange floor pump after all.

I hope this can help someone.


Shimano a410 compatible brifters Which brifters are compatible with Shimano RX100-A410 2x7 drivetrain?

Microshift SB-R472s perhaps?

Thank you for your time.

You can basically use any 7 speed Shimano brifter except for 7 speed dura-ace (which had a different cable pull). All the 7 speed Shimano rear derailleurs (road/mountain) except of dura-ace have the same cable pull. And you're fine with road front derailleur compatibility within Shimano.

The current Shimano brifter that is compatible is the Shimano ST-A070, from the Tourney line. The Microshift SB-R472 also works.


Does a brand-new bike bought online need a service before riding it? I bought a brand-new road bike from a website.

The bike was preassembled and delivered in a big box.

The only things I had do were:
 - remove the styrofoam wrappings
 - screw on the pedals
 - loosen/reposition/tighten the handle bar (when the bike was delivered, the handle-bar was rotated and hooked under the top-tube so it was more compact for shipping)
 - adjust the height of the saddle

I have ridden the bike.  The tyres were already inflated.  The gear shifting works fine.  The brakes work.  The wheels spin fine.

But I noticed a (very) slight rattling noise (as if from the chain).

I took my bike to a local bike shop.  The man there told me the bike needs a service and it would cost £50.  He claimed it would make the bike "safe" to ride, and if I had bought the bike from his shop (a physical shop instead of a website), it would be "put together properly".

The cost of £50 was a little more than what I expected.  This is a brand-new bike, after all.

So my question is: should I get this brand-new bike serviced before I ride it?

Or are there some simple things I can do myself?  I can of course tighten everything with an allen key.  I can also lubricate the chain
and sprockets (or do I need to that?  I read somewhere that brand-new bikes all have been lubricated in the factory before they're sold.)

What else must I check (either myself or by a bike shop)?

Is it a not a good idea to start riding the bike without getting it serviced first?

Thank you for your input.

I took the bike to another bike shop.

The man there adjusted my handle bar (apparently when I did it myself, it was not good enough, not straight or aligned).

Then he put the bike on a stand and checked gear shifting to all the gears.  It all worked fine.

He also pointed out the slight rattling noise I heard is caused by the chain rubbing against the front derailleur.  This is normal and can be corrected by "trimming".  This YouTube video explains "trimming" the front derailleur.

The man said the bike is fine to ride.  I asked him when I should get it serviced, he said: "in 3 to 6 months, depending on how much you ride."

He also said not to put any lubricant on the chain because the factory has already done that.

I was in the shop for 10 minutes and he didn't charge me anything, even though I was more than happy to pay him for his courteous and informative service.

Clearly this is the shop I'll take my bike to for the next service.

So to answer my own question, it's advisable to have a professional check out the bike before you ride it, unless you're experienced with bikes yourself.  You don't need a "service" per se.

Like with all new products, one should study the owner's manual before thinking there's something wrong with the product.  I should think the owner's manual discusses "trimming".


I'm shopping for a child trailer. Should I get one with suspension? I'm shopping for a child trailer. Models with suspension get quite expensive, but it seems like that would be a great feature to reduce strain on the kiddo.

If you have a trailer with suspension, do you find that it actually provides some benefit?

I'm currently looking at the Burley Solo.

I have a trailer with suspension, but I don't believe it has provided much benefit while cycling.  Mine is multi-use (jogger, stroller, ski) and I have found it has provided some benefit while hiking.

On the cycling side of things, most of the time I am pulling the trailer with a rigid bike (no suspension).  I am riding with 5 weight bearing contact points while my kiddos are riding with a full body contact area and no need to maintain control (which is what suspension is designed for).  When they were younger, my trailer had an infant sling that kept them fully suspended (similar to a hammock).  Now that they are old enough and large enough, they sit in the trailer proper and receive what I perceive to be very little benefit from the suspension while I receive the extra benefit of pulling it's weight.

I have been very grateful for the suspension on a few hiking trips when taking them down a rock garden.  However, the vast majority of the time, cycling, I'd prefer to not be towing the extra weight.


Tire compatibility for hybrid cruiser I have a 28" Schwinn Yorkshire 700c hybrid cruiser. I got it since it was the only one in my price range but the problem is the tires are too slim for me and I'm used to much wider ones, so I was wondering what kind of wide tires are compatible with it?

It would help if you posted a picture of your current setup in order to see how much clearance you have, but, any 700c or 29" tire will work provided it's not too wide to fit in your frame. Your local bike shop should have a wide assortment of tires that are suitable.


Mounting Shimano Acera Derailleur: Supposed Gap? When installing a new Shimano Acera derailleur instead of an old, broken one (same model), I noticed that there is a little "opening" (marked in red) in the "frame" around the bolt that connects the derailleur to the bike, and it seems to be the negative shape of the bike frame (also in red, second picture).

first picture:

second picture:

However, I cannot get them aligned, due to the parts marked with yellow. If they were aligned, it seems that I could just screw the whole derailleur a tad closer to the bike, and this gap would give more stability with respect to rotation, which would seem reasonable to me.

I found no instructions for this problem online (except an explanation of the purpose of that screw by the yellow-marked area), but I want to be sure that I am not getting on my bike with a screw not as fastened as it should be.

I think the yellow landing is for the B tension screw to press against.  That will adjust how hard the derailleur pushes away from the cassette, essentially adjusting the gap when its at the big cog on the cassette.

Small chance that your new derailleur is for a different style of hanger ?

Do you still have the old derailleur to compare?


Are road brakes designed not to brake too much? All of my cycling fellows always told me that it's much more difficult to fully stop a road bike, compared to a mountain bike, because "road brakes just don't work so well" (and perhaps because of skinnier tires).

When I started to ride bikes with road wheels (700x23) and dual-caliper road brakes, quite a few years ago, I noticed my brand new Tiagra brakes were lame compared to even MTB cantilevers, and I ended up replacing the pads by v-brake ones (glad I did).

But I have also noticing the relative danger of "cascading braking" in a tight pack, which can cause severe rear-collisions.

So my question is: are road brakes designed to have less braking power than MTB ones, in order to avoid peloton accidents or whatever? Or is it incidental? Or yet, actually only the lower-end ones don't brake so well?

I'm not sure "designed" is the correct word, evolved comes much closer. Current dual caliper brakes actually stop a lot better than previous single caliper sidepulls. There has always been a compromise between weight and braking power. The designers have focused on how light they can make a brake that stops "enough". I don't think there has been any effort to deliberately reduce the performance.

Older centerpull brakes such as the MAFAC Racer actually compare quite well to current dual calipers, but they are much heavier and more complex to install. Designers switched
to sidepulls to save weight, but then compromised braking performance.

The problem is that you can only do so much with a rim brake without risking locking up the wheel. You get the most effective braking by stopping just short of the point of locking up the wheel. ( This is called modulation). Given the nature of rim brakes it's very difficult to increase the braking force while still maintaining sufficient modulation. This is the advantage that disk brakes common to MTB provide.


Another stem diameter question (French steerer) The steerer in the French bike I'm restoring has about .2mm less diameter than "regular" ones. With some grease, I manage to fit the "regular" cinelli stem I will use into the steerer. (Mine is the opposite problem as this.)

I'm inclined to I leave it thus. What are the odds that stem and steerer will freeze after some time, making removal hard/impossible?

The alternative is to sand down the stem to get a more easy fit. Downside is that sanding means the end of the stem's very nice looks, forever.

I will be grateful for anyone with advice to offer.

Your main concern of the stem becoming stuck, is valid. It requires you to remove the stem and re-grease it more often than you otherwise might. I'd recommend twice a year minimum. Sanding the stem is a viable option, first determine how high you need the handlebars to be, then rap tape over the part you are sure you want exposed above the locknut of your headset, then sand for 10 minutes, and check if it fits. You may need to sand the wedge as well. If it doesn't fit yet, sand it again and check every minute or so, it usually takes about 15 minutes or so. I've had AVA stems fail before and I was very lucky, Cinelli, TTT, and others made stems for French bikes and 25.0 handlebars, but they're getting hard to find. I prefer sanding Nitto stems as they are well made and have models to get the bars up higher for riders who need a more upright position.


Making a very sharp turn by pivoting on your front wheel? There is that cool maneuver that lets you do a very sharp turn (90° or even 180°) in very tight situations, like descending two flights of staircases (in town) or narrow and very steep winding trails (in nature).

It involves pressing the front brake so the front wheel locks, and the rear wheel rises into the air. You would then place the rear wheel back down wherever you want, disengage the front brake, and continue riding in the new direction.

I saw an owner of a bike shop do this once, but have seen it only in online videos since then.

So, how is this maneuver called? I saw names like "endo" or "stoppie", but "endo" seems to refer to accidents, and "stoppie" seems to mean a "trick", only done for the cool look. Does there exist a name that implies doing this in a mundane way, like when one's commute route just appears to have an angled staircase in it?

In addition (if this is not too much to ask in the same question) - how to practice this?

In german this is called "Hinterrad versetzen" -- "displacing the back wheel". I got to learn this in an mtb course I took a while back. If you can, try to find an instructor or other experienced rider to teach you.

How to practice:

Start very, very small and always wear full protective gear, i.e. a full-face helmet and vest in case you crash. You will crash. Be prepared. Have a friend with you just in case.

Look for an open, empty and even space like a parking lot or similar where you can brake without fear of slipping. If possible, avoid concrete or similar very hard surfaces.

First, you practice the stoppie, without turning. Start small, i.e. just lift your back wheel a couple of centimetres. You don't need to ride very fast, it's mostly about the balance on the bike. It's absolutely possible to do this from a walking pace. Instead of moving your weight far back, as you normally would in a hard stop, keep it (more or less) in front. Find the point where it's easy to lift the back wheel without getting the feeling you will crash any moment. Do this a couple of times. Slowly increase the height of the back wheel.

Do only the stoppie until you feel comfortable "standing on your front wheel" for a second or two without losing control.

If you feel safe holding the stoppie, try pushing your back wheel around a couple of centimetres by letting the inertia turn the bike. You need only provide the tiniest motion yourself, physics will do the rest. Slowly increase the arc until you are where you want to be.

Note 1. If you have front suspension, beware of your fork kicking back when in the stoppie. This can easily overturn you.

Note 2. I wouldn't try this on stairs or a rocky or otherwise dangerous path until I was absolutely sure I can do it. Also, don't force it. Practicing this kind of thing takes time and drains you faster than you think. Try integrating training into normal rides instead of riding out just to train.


Short vs Long brake pads (with v-brakes) on road bike rims at high speed Would v-brakes with the normal v-brake long pads (as opposed to shorter brake pads) on road rims exhibit any problematic behavior going downhill at speeds of 50 mph?  I am concerned that the longer brake pad may be more susceptible to shudder and/or grabbiness than shorter pads.

Background:

The bike in question is a Surly Cross Check which is set up with brake posts for cantilever or v-brake.  Caliper is not an option.

The brakes I have ready to put on are Deore XT br-t780 (with long brake pads) , front and back.

Other v-brakes with shorter pads are available, e.g., Shimano BR-M422.  (But these M422 are much lower quality than the T780 - and the question is about long vs short pads, not quality of the brakes they come with).

The cable travel in the lever is not an issue as I have the problem solver travel device ready.

You should not have a problem.

In fact it should be easier to set the toe as well as the alignment. Assuming the block widths are about the same, you should see better stopping power as well as cooling.

I go long, esp. cause I'm +90kg and enjoy speed.

Shudder and "grabbiness" are typical toe issues. If you follow the pad instructions or any of the hundreds of guides available online, you'll get real good at setting the toe and get the most out of them.

It is the most common issue I fix for friends who's "bikes don't work".


What is the standard diameter for BMX brake mounts First of, these are the sort of brake mounts I'm talking about (though I believe the diameter is standard whether the mounts are removable or welded to the frame/forks):

What is the diameter on the shaft of the mount (marked in the picture with a C) where the brake arm is attached?

I measured several sets that I have and got the following results. These were used with Shimano, Tektro, Avid and one with "no name" brakes.  This not to say that some other brands don't have a unique size. The male threads that go into the frame were either M6 by 15mm long or M8 by 10mm long. The shaft or studs (part labeled as C) were all just under 8mm, 7.93, 7.90, 7.89 etc. The threaded female hole were all M6. The M8 by 10mm posts all came off of rear brake mounts. The use of the larger diameter and shorter length may be due to the smaller diameter of the seat stay tubing.


What is the minimal seat post depth? This may depend on the seat post and the fixture, but how deep should my seat post be into the frame? I have a bike that came with a post that is pretty long and I cut an inch off the bottom of the post a couple months back so that I could sit lower, now I'm considering cutting two to 4.5 more inches off so I can get further down on the bike during some technical riding and so that I can pump deeper. How far into the bike does the seat post need to go before stability is compromised? Are there any other risks of having your seat post not too deep?

Most seat posts have a "minimum" insert of 3 to 4 inches.  But this varies with the material and the thickness of the post, and the weight of the rider means the minimum might still be too little.

As a tall rider I frequently have my seatposts up to maximum, and have bent several over time, and have fractured one frame.  Now I always buy a 450 mm or 500 mm post and almost always reinforce it with an insert tube up the middle.  I will not ride a seat post without 5" of frame insertion.

Since you sound like a MTB kind of rider, consider a dropper post rather than chopping ruthlessly through your seat poles with a hacksaw.  These are intended to go at a good height for normal efficient riding, but you can turn the interlock and they slide down ready for low-seat technical riding.  I understand you can do it one-handed while rolling too.

Once you're done you can raise the seat again without stopping.  Downside is they probably cost ten times more than a normal seatpost.


Recommendations for transporting twins on the front of a bike are there any child seats that can be used for twins (6 month old)? I don't like the idea of putting them in a trailer as I suspect its easy for cars to not see it.

Also - special bonus point to anyone who knows of a solution that is compatible with a tag along bike (used by a five year old)!

Edit I am discussing some custom options with local bike mechanic, will report back when I have update.

An alternative to long tail bicycles is long wheelbase bicycles:


What is the name of those Old Timey Bikes? The bikes with a huge front wheel and small rear, with the cranks attached directly to the front wheel... What are they called?

Additionally, it seems they need to be very tall in order for you to achieve a full pedal stroke, so how is one supposed to mount this archaic device?

This is a "penny-farthing" bike. You mount it by putting a foot on the step above the back wheel, you push off, then climb up it towards the pedals as it moves away. (Like this video shows.)

The front wheel was so large for a couple of reasons: Since the pedals were connected directly to the wheel, the bike could go faster if the wheel were larger; and also, a large wheel functioned as suspension.

When the safety bicycle was introduced, it had pneumatic tires and drivetrains that allowed for gearing independent of wheel size, so the penny-farthing fell into disuse.


Can't get enough braking power after lots of adjustment Hi :) I just bought a 2015 Specialized Diverge A1 with almost completely stock components. With some adjustments everything seems to work well except for the disc brakes.
This bike has a Shimano Claris 2x8 groupset and the mechanical disc brakes are Promax Render R.
I've ridden other road and gravel bikes before with mechanical disc brakes, and never felt unsure about stopping power, whether from the hoods or drops, until now. That's just to say I know what a brake should feel like, and I have decent hand strength. With this particular bike and brakes, I can hardly squeeze the levers if I'm riding on the hoods, and even if I get maximum leverage riding in the drops and can squeeze all the way, the stopping power is terrible. There's no hope of locking the wheels even just going 5mph. It's a very slow, weak rolling stop.
I've tried checking and adjusting just about everything I could think of or google, to no avail. I'll go through what I've tried:

realigning brakes

barrel adjusters

adjusting the internal pad to rotor distance (don't know if there's a better term for that) both closer to the rotor, to see if less travel and squeezing as hard as I can would help, and farther from the rotor, to see if more travel made it easier to squeeze the lever from the hood. Closer to the rotor was slightly better.

inspecting and replacing pads. They didn't look very worn or warped (definitely at least 3mm of material left on each pad) but i replaced them anyway

rotors do not look warped/bent either

cable tension. Can't find a happy medium where there's enough tension for the pads to clamp hard on the rotor and there's enough slack that i can move the lever effectively from the hoods.

cable/housing condition. Looks very clean. If I release all tension from the cables, the levers move freely. I don't feel any friction.

these levers don't have the built in reach adjustment, so I put in shims to bring them a bit closer to my fingers to make it easier to squeeze. Not enough help.

In summary,
I can't get enough stopping power with my disc brakes, and I'm also finding it practically impossible to squeeze the levers effectively from the hoods. They feel so stiff.
In terms of my inability to squeeze from the hoods, do my hands just hate this Claris lever/hood geometry? Are they weaker than I think? For the lack of braking power, is there some adjustment I missed? Is something else going on?
I'm doing all I can to fix this myself even though I'm a total novice, so any help is greatly appreciated :)

Render R's are very susceptible to the arm being over-actuated. They don't hit a physical stop like some of their peers, but they reach a point where the cable anchor location is hanging in space and can't be pulled anymore. That you can't get good power even braking from the drops suggests this is the problem.
Detach the cable. Set the barrel adjuster all the way in. Loosen the caliper mounting bolts. Anchor the cable with the smallest amount of arm actuation you can while avoiding slack. Dial in the stationary pad adjuster until the lever feel is what you're looking for as a final adjustment. Tighten the caliper mounting bolts and get your pad gap dialed by squinting at it good. Even if getting free of rub is tough, trying this may tell you why power was lacking.
Like all mechanical disc calipers, this brake benefits highly from compressionless housing. Faced posts and compressionless usually let this brake perform fairly well. Also like all mechanical discs, small issues with the cable and housing setup can result in major issues with power and the levers bottoming too easily. Badly prepped housing ends, or housing ends not fully seated in the levers, can be an example.


Road tubeless puncture I've suffered a small puncture on my tubeless tyres. It spat out some sealant and then seemed to be OK for a while. But today it couldn't hold a decent pressure.

How can I repair this?
Just put some more sealant in and hope?
Put an inner tube patch inside the tyre?

Both approaches may work if you are lucky. It depends whether you are willing to sacrifice the additional sealant if it does not or whether you are willing to sacrifice the sealant that is already there when cleaning the tyre.

If there is some still some good amount of sealant inside, you can also use tubeless plugs (worms), but they are not permanent, although they can work for many months or perhaps even years, if you are lucky.

With the plugs you do not have to take the tyre off the rim and you can do the repair on the road.

After some time it is better to replace the plug with a patch from the inside. Do it when there is a good time and you have the tyre dry off the rim anyway. Some companies sell dedicated tubeless patches. They are the same as tube patches but are somewhat thicker or bigger but a tube patch can work as well depending on the size of the cut.

Some also sell big patches that are used at the outside of they tyre, but I have no experience with them and I would fear the uneven diameter it would cause.

Your hole looks pretty small and should theoretically be fixable by the sealant. Make sure you always shake the bottle well to allow any big particles to get into the tyre. Some sealants have such big particles that they even do not go well through a syringe and are better poured directly into the tyre. That is my experience with Joe's.


Is there a ranking of bicycle manufacturer brands in terms of quality? How much does actual branding weigh in these days when it comes to buying a bicycle of an established brand (i.e from a bicycle store)? Or is it all about the components and the brand is just a label?

Major brands make a wide range of bikes, some of which are great, others not so much. To further complicate things, some brands license their name to bso's on top of their normal decent quality sales (e.g. Schwinn). So, you can't really rank them on quality in a meaningful sense; just compare a subset of models across manufacturers.

That being said, what are you getting when you buy brand X? Well, it's similar to buying a car. A brand is associated to some extent with prestige, quality and value. Also, how much support you can expect if things are going south (e.g. if there is a frame defect, will the warranty honor it). Giant probably would; Random chinese shop on Alibaba probably won't exist by the time you complain. You are putting a good amount of trust in a bicycle to actually be safe and able to do what its supposed to; that trust is easier to put in when the bicycle is from a quality manufacturer.

At a given price point, different brands will have different components and frame+fork designs. Some of the price is due to marketing/brand name (e.g. if you had an Audi and VW badge on two identical cars, the Audi one would sell for a bit more) and the cut the shop needs to take to stay in business. Other parts of the price are engineering and components.

Note that if you spend more on one part, it means you're going to have to cut somewhere else. Thus, you need to compare bikes (after riding them, hopefully) in order to see whats a good value and fit for you.

Also, note that spending more or going for a less well known brand is not necessarily good or bad. For example, REI used to sell some pretty decent touring bikes under their less well known Novara house brand for considerably cheaper than the usual Trek 520 / Surly Long Haul Trucker / similar.


Diamondback Century 2 (2015): What thru-axle skewer dimensions fit the original axle hubs? Lost the originals/internet search unhelpful As the title says, I lost the original axle hub skewers (both front and back) while moving. I bought this bike secondhand over a year ago, and it's a 2015 Diamondback Century 2. Diamondback no longer hosts the product specifications and won't respond to my customer support request, for some reason. I can tell you the original axle hubs are in place.

I did find the product specifications of this model/year on REI, however, they only list the rear/front hub specifications as DB-24H (rear) and DB-20H (front), with no mention of the dimensions (in any way I would understand).

Could anyone help me understand better how to figure this out, maybe using the information from REI above? Also, any tips/direction on what brand/website would be a good place to find replacement skewers. I'm seeing a wide range of prices online and many of them don't even list their product dimensions.

Thank you!
John

First, do you have quick releases, or do you have thru-axles? If you have rim brakes, then you have QRs. Any QR will fit your bike. If you have disc brakes (look for a rotor on the left side of each hub), you probably have thru-axles, but it's also possible you have QRs.

If you have thru-axles, you probably need to call Diamondback Bikes. Their FAQ lists a number for consumers to call about replacement parts. Because REI is a national chain of outdoor equipment stores in the US, if you're still in the US, you may be able to get to one, and they may be able to help you as well - although they may not have the correct information on hand themselves and probably don't stock replacement thru axles for every bike, so they would probably end up reaching out to Diamondback themselves.

Since you asked, we should discuss the dimensions of thru-axles! As you've noticed, they are more complicated than quick release skewers. QRs can have a bit of the rod poking out the frame end, so they could be made to standard lengths. The over locknut diameter of rear road and MTB QR hubs is slightly different (130mm and 135mm), and that was the only point of differentiation. In fact, an MTB rear QR will fit a road bike, you'll just have some rod sticking out the left side of the bike. Front QRs are the same width between road and mountain bikes. Also, some early disc brake bikes took QRs, although by 2015, chances are you should have had TAs if the bike were disc brake.

First, there's the axle diameter. The current Century 2 has a 12mm diameter axle in front, and a 12mm axle in the rear. Many mountain bikes and some gravel bikes take 15mm axles in front. Many current mountain bikes take wider hubs than the current road standard of 100mm front, 142mm rear. In any case, chances are that your bike takes that standard.

From there, I'd refer you to the Robert Axle Project (note, they make and sell thru axles), or to this page on Modern Bike. Because forks vary in how thick they are at the dropouts, thru axles also vary in their length. So, a 12x100 front thru axle is really longer than 100mm - RAP's site says that a 125mm thru axle would fit my gravel bike.

Another aspect is the thread pitch, or the distance from one thread to the next one on the threaded part. Thread pitches can be 1.0mm, 1.5mm, or 1.75mm.

Last, not discussed on either site, but thru axles can have flat seats or conical ones.

RAP does have a bike database, and it has some information on Diamondback bikes. It is able to suggest a front thru-axle that should fit all Diamondbacks. However, it's not able to suggest a rear thru-axle for your model. It suggests measuring your thru-axle ... which you don't have. This, unfortunately, is a lesson not to lose your thru-axle. If you're transporting the bike with wheels off, best practice would be to thread the axles into the frame. In any case, it does seem like calling Diamondback is the best option.


How can one prevent a tube from sticking to the inside of a tire? I was cleaning my cruiser today, and as part of that I removed the tires from the rims to give them a good scrubbing. As sometimes happens, the tubes were stuck to the insides of the tires. (This also happens with some of my other bikes sometimes.)

While I was able to slowly peel the deflated tubes away from the tires, this can't be good for them! Is there a way that this can be avoided when reinstalling the tubes and tires onto the rims? This bike has had slow leaks in the past, and I'd like to take precautions against that happening again.

Baby powder works great and is very inexpensive.


QUARQ DFour installation on Shimano bike I'd like to replace my Ultegra 6800 crankset with QUARQ DFour powermeter. But I don't know how to choose between BB30 and GXP versions. I have Shimano Pressfit SM-BB92-41B bottom bracket. Do I need to replace my bottom bracket or use some adapters?

Your Shimano SM-BB92-41B is a BB92 standard bottom bracket.

Quarq's page lists GXP, Press Fit GXP, BB30, Press Fit 30, BBright, BB386EVO, BB30A, PF30A as compatible bottom brackets.

I believe the Press Fit GXP from SRAM is a BB92 standard bottom bracket. See https://www.parktool.com/blog/repair-help/bottom-bracket-standards-1#article-section-4.

So the GXP version is the  one you want. It would be nice if Quarq provided a better compatibility guide.