How do I prevent my chain from dropping down while going downhill on bumpy surfaces? I have a Merida Duke 650 hardtail mountain bike.

The issue with my bike is the chain continuously keeps coming out of gear while I am going down hill on bumpy surfaces.

Is this happening because my rear derailleur is too soft?

Is there a quick fix or trick to avoid this from happening?

There is no easy and free solution for this, since your bike is not meant to be going downhill.

The best thing you can do is go downhill using the largest front chainring and a pretty large rear cog (but not the largest). This will ensure a pretty good rear derailleur tension which will most probably prevent the chain fall.

If you are willing to spend money on this you could convert to 1x10 or 1x11 (after making sure that the gearing will be good for your rides) and use a narrow wide chainring and a derailleur with a clutch mechanism.


SOMEONE HELP PLEASE:( I'm getting a new bike and i'm wondering if a Shimano TX50 front derailleur is good enough and will do the job or should I get another bike which has an acera, FD-M390 front derailleur. Thanks in advance for ur help!

Front derailleur is not a particularly important component to optimise, in my opinion, since it only touches the chain when being operated (assuming it is correctly set up so the chain doesn't rub). I doubt Shimano sells any derailleurs that don't "do the job" of shifting gears, so at worst the shifting in the front will be a bit worse and the components will weigh a bit more.

You can also switch the derailleur later, and especially the front ones are not particularly expensive (in fact both of the ones you mentioned are such low-end ones that it would make little sense to buy either separately).

So, choose the bike that has the nicest frame, fit, and feel for you. Replace individual components later if you are not happy with some of them.


Mismatched chain and chainring Why specifically would shifting between chainrings of one speed type with a chain of another cause problems?

As I understand it, all 3/32 inch chains have that as their interior width; the variance in chain speeds comes from their external width. Meaning I can put this 8 speed crankset on the 11 speed bike I forgot to get a crankset for, right?

According to this forum post I will run into problems if I try to shift between the chainrings...

is that just because of the difference in distance travelled by the different speeded front derailleurs? Meaning that if i used an 8 speed front derailleur I'd not have trouble

An 11-speed chain will mesh with and be driven by a ring designated 8-speed without issue, barring corner case exceptions. (There's nothing necessarily stopping manufacturers from cheating or being sloppy with keeping everything that's nominally 3/32 cross-compatible even with parts of disparate eras/types as in this example, but it's not an issue one sees too much of.)

If you did have issues shifting, it could be a combination of chain outer width, FD travel, side plate profiling being a poor match, and/or the chain's potential ability to get stuck between rings, which I have seen albeit not often.

One confusing thing about this topic is that chainring spacing is one of the least standardized things on bikes, it varies a little but not much between speed generations, the numbers are close to one another but not identical for how each manufacturer does things for different speed generations, and what actually determines the spacing is a combination of ring thickness, spider tab thickness, tooth offset, and presence or absence of spacers, so non-stock chainrings being in the mix can easily affect the actual spacing.

Usually combinations like what you propose can be made to work. Often they work well. But it's never a guarantee they work, or work without compromised shifting performance.

Part of what makes the issue murky is that in terms of professional shop practice, writing up a work order to create this kind of setup for a customer as a repair, build, or upgrade is pretty tenuous at best. In that context, setting yourself up to mess with something finicky that might not even work or be highly compromised is a great way of wasting time and creating a complicated situation. So bike shops and pro mechanics have good reason to take a different baseline attitude on the topic than a home mechanic.

Presuming we're talking about road, in the case of 11-speed, part of what you're up against here is that 11-speed front derailers often act like they barely have enough total travel even when everything is as the manufacturer intended, particularly Shimano ones. It would in no case be surprising to me if this were enough to keep what you're proposing from working. It may also be able to work fine, or you may be able to hack the cable anchor position for more travel.

Putting a narrower chain in a wider front derailer cage usually works extremely badly, especially multiple width generations apart. The usual problem (for a double) is that by the time you've gotten the low limit adjusted so the inner cage is close enough to the chain to get a good shift off the small ring, it wants to have way too much gap with the outer cage once you're on the big ring, and chain drop and poor downshifting result. Triples compound the problem. This can potentially be mitigated by manipulating (squeezing closed) the cage. When it's multiple width generations like this I personally just don't do it, even on my own bikes.  If you decide to it's going to be an experiment where you're completely out your FD if it doesn't work.

One thing you see parroted on the internet is a "a front derailer is a front derailer," as in they have a great degree of interchangeability, which is just not reality. Cage width, profile, actuation ratio, and in the case of triples minimum mid-to-high tooth difference spec are all critical.


How much faster can my commute be if I use a power meter? When biking to work, my routes have have stop signs, stop lights, and other interruptions every few blocks or so.

My understanding is that if I reach my power at target heart rate soon after stopping so that I still save glycogen, my commutes would be faster. I'm commuting five days a week. How effective is it really in practice? How much would I expect my average speed to increase?

Update with examples.

After stopping at stop signs, I plan to accelerate by keeping my power around 150W depending on my fitness.

After stopping at traffic lights, I plan to gradually raise my power to 150W because my heart rate would drop.

In both cases, my heart rate shouldn't exceed 180-age. With power, I know that I'm not overshooting it.

Update: Sample morning race to work ride in response to a comment.

With that many interruptions your own performance is unlikely to make much difference to your commute times. Sprinting for the lights, when safe, is much more likely to help. If it's mostly stop signs rather than lights, getting going fast might help but you don't need a power meter to tell you that. For me, leaving a few minutes later in the morning makes much more difference - not only are there more cars going my way and holding me up, but there are more coming the other way on narrow roads so passing the queues becomes harder. Bin day or a badly parked delivery van jump out of a list of timings.

You don't say anything about the distance and time but I assume you measure it. Have a look at the variability over recent rides, and try changing a few variables - can you even tell the difference between holding back until the fast bits, and going at everything hard?

A power meter is a training tool, and while you can incorporate commutes into a training plan that doesn't sound like what you're doing. Personally I prefer not to have a screen when commuting in case I look at it; I'd rather keep my eyes on the road. But maybe your commutes are in more benign conditions.


Suspension fork swap for rigid: axle-to-crown confusion I'm looking to replace the suspension fork on my bike with a rigid one. After much soul searching I've tentatively settled on the Surly 1x1. What's got me wrapped around the axle (pun intended!) is the axle-to-crown measurement.

The fork I have now is the SR Suntour SF13-XCT, which came stock on my Specialized mountain bike. This fork is listed as having 80mm of travel and a 459mm total length. When measuring the distance between this fork's axle & crown I've gotten very close to the 459mm listed on Suntour's site, which leads me to believe that the 459mm length listed by Suntour is correct.

The Surly 1x1 I'm looking at has two versions: one "corrected" for suspension travel of 80mm (axle-to-crown length of 413mm), the other "corrected" for suspension travel of 100mm (axle-to-crown length of 453mm).

Both of the Surly A-to-C measurements are below the 459mm that I supposedly have to put in if my geometry & handling are to stay the same.

In addition, the zip tie method allowed me to measure my sag as 18mm. (I normally keep my fork on its highest preload setting.)

Now, for the question itself: Which of the two Surly 1x1's should I get? Should I, or should I not, take my sag into account, considering that Surly's forks appear to have been "corrected" for suspension travel already?

Thanks in advance for any guidance.

Definitely you have to account for sag when measuring axle to crown distance, because that is the real geometry of the bike when it is actually being ridden. If you mention in this bike sag is 18 mm when you ride it, it should mean that your actual axle to crown distance is 459-18 = 441, thus suggesting you should use the fork corrected for 80mm travel.

Ideally you want to keep the geometry of the bike, particularly head tube angle and bottom bracket height (or pedal to ground clearance). Both are important. Head tube angle affects the steering response of the bike. Bottom bracket height defines how tall an object can be for you to roll over it without hitting it, and how much you can lean towards the side before the pedal hits the ground while pedaling (you should not put the "inner" pedal down while turning)

A bike with suspension fork actually changes it's geometry while riding due to the travel of the fork, and this is no trouble at all (for most riders), that means that a small variation in axle to crown distance would not terribly affect the bike handling characteristics.

In this case, if you chose the taller fork, you'd give your bike a slacker head tube angle, making it feel a bit less responsive on the steering, which in turn means (a little) more stability at high speed, and you would gain a few millimeters on pedal clearance. If you had the option for a third fork, shorter than the ones you already described, you'd get a bike with a steeper head tube angle, which gives a more responsive steering, the bike would feel very agile, but less stable, and you would loose a little pedal clearance.


Converting friction shifters to SIS or STI shifters Edit: I'm now worried the main issue might be if it's at all possible to mount cable stops to the top mount position the cables exit the DT into the shifters.
As I mentioned, I'm not there to take more photos at the moment, but you could see a bit better if you open the photo attached to max size.
I do actually prefer STI, realized this after posting. need to understand if that's ruled out, and if so - if there are any SIS shifters that would fit as replacement.
I hope there's a solution that doesn't require serious engineering.

Edit 2:
Attaching pics I found for someone with roughly the same bike who performed the same conversion I'm trying to make.
It requires some machining, but if I can do that, it might be the better option in my opinion over SIS. *I still don't even know if I can get SIS shifters to fit the mount I have.
Also attaching better pictures of my top mounted shifters - fitted on a boss that isn't identical, although the machined part I require is probably the same.
For the part I need to prepare, I'm still waiting to hear from the owner of the bike in the photo, hoping to get a few more angles and possibly dimensions so I can replicate it. I'm curious about the reverse angle, probably showing how the exposed cables go into the new piece.

The last two pics show how the cables are currently routed under the BB

Surprisingly this seems more crude than the guide system on an earlier 80-81 model, with a practically identical frame:

This is continuing another thread I started, asking advice on whether I should buy a used groupset.
The most thorough advice I got there, suggested replacing my 6s freewheel to a 7s one, and couple that with 8s STI shifters - my purpose was actually converting to STI.
I'm now trying to figure out if I might be better overall converting to 7s SIS.
Arguments for 8s STI:

I was told 8s STI shifters should work fine with a 7s freewheel, and that even the people at Shimano said so.
Brifters are easier to use.

Cons:

some people say 8s shifters with a 7s freewheel isn't a perfect match
I'll have to use cable stops, I'm still not sure how to go about this on my frame - the tutorials I saw had the break cables routed outside the frame, not inside it, and they were also positioned at the side of the downtube

Arguments for 7s SIS:
Its all pretty much said above -

Should be no argument about compatibility with a 7s freewheel
I don't have to deal with the cable stop issue, easier installation overall.

Cons:

Less comfortable shifting
My old friction shifters were so finicky that I'm prejudiced against all downtube shifters

Anyone with experience and opinions to contribute?
It would be great to understand if there's anything special I need to take into account considering the position of my current shifters and the routing through the tube.
Thanks
Editing to answer a question I got:
The frame is aluminum, with 126mm spacing. Which means it's not a candidate for cold setting, and therefore can't take anything more than a 7s freewheel - as far as I understand. And as Nathan pointed out in the previous thread I linked to, the dropouts are enormous and might not be great for flexing. I'm not there to measure the actual spacing, but the literature has it as 126

Since you're going to a lot of work, moving to 8 speed (or 9 or 10) sets you up for the most flexibility.
The main reason is that you need a new rear hub with a cassette-freehub.  There's no good way to convert a freewheel based wheel.  Since you're buying a replacement hub/wheel, its no more work to pick an 8~10 speed one.
The OLD of your bike needs to match the hub, so measure that first.  If its 126mm, you'll have to decide if you want to cold-set your frame.  Is your frame steel? It could be aluminium from the photo, which doesn't cold set.

You will need a full set of parts, plus substitutes for the fittings missing on your frame.
Starting at the top, the brifters should just slide onto your drops and bolt up.  You will need to either carefully unwrap the existing bartape to reuse, or buy some new.
Next are the downtube stops. Your frame has nice but unusual shift levers - the more common ones are two lugs horizontally out the sides.  For them its possible to buy bosses that create stop points.

There are other options - you might choose a "band-on" cable stop like this:

or if you're happy with welding/brazing/2-part epoxy then stick-on ones might suit.

Ideally you'll be able to use the existing cable track under the BB, the photo isn't clear how the internal cable exits the downtube.

If you want to somehow tie the new brifters into the existing access holes on top of the downtube, well that's going to need some engineering and likely a frame builder.
One possibility might be to use Nokon-style cable housing to run from your brifters all the way down to the existing cable entry holes, but that could leave some loops of outer that will look weird.  There could also be stresses on the cable as it passes through at least one 90-degree bend, maybe two.

Additionally, I found that the Klein downtube bosses had some kind of weakness in the past.  Details are from https://www.bikeforums.net/bicycle-mechanics/729717-hillrider-s-klein-stage-comp-fix-shifter-boss-bolt-stripping.html
In summary:  the bosses are weak and there's a refit kit to make them stronger.  However the instructions suggest the existing boss is only bolted to the frame, so it may be possible to unbolt, for a cleaner look.
With the knowledge Top-mount downtube shifter I found this rare Suntour adapter - you might choose to use this as inspiration to make your own, or talk to a machinist to get something made:
   from https://www.bikeforums.net/classic-vintage/1163305-how-use-ergo-sti-shifters-aero-dt-shifter-mount.html some gorgeous photos there
And here's someone who secured normal lugs to his Klein:
 from https://www.bicycles.net.au/forums/viewtopic.php?t=30867

Finally, whatever you do, save the take-off pieces.  Someday you or a future owner might want to restore the bike to original, and these levers are rare.  So please don't throw them out.  You might even choose to sell all the takeoff parts to help fund your changes, but don't bin them.


Hollowtech 2 cranks and bb how good they are? I have been commuting by a bike for 6 months on a 9 speed bike. It has a standard squared taped BB and cranks screwed on it. Now I have heard those Hollowtech 2 cranks and BB and how they can improve efficiency and putting bearings outside BB (not sure if I am saying it correctly).
So how good they are? I could actually feel the improvement when I changed from a 32mm tyre to a 23 mm high pressure tyre couple of months ago. I am thinking of upgrading if worthwhile. Thanks.

They are easier to install and maintain, and depending can be lighter.  However, it's not likely that you will notice any great difference in efficiency commuting on them.  Probably not even 10% of the difference you would notice in a tire change (assuming the old bottom bracket and cranks were in good working order).


How much assembly is required when an LBS orders a bike? I'm looking to order a Marin Lombard Elite from my LBS but I want to replace the FSA BB and crankset with Shimano or SRAM parts, and change to a 52/36.

When my LBS orders it, does all of that come assembled from the manufacturer usually?  If the former, I'll just take it home and swap everything out myself, but if the latter, then I could bring them the parts when I place the order and they could just swap them in when they build it.

This is determined by your LBS, the relationship you have with them and the bike your buying.

Generally bikes come in flat pack boxes and, with the exception of top end bikes, are partially assembled out of the factory. The reseller needs to attach the handle bar and do a safety check. If you want to change parts out you'll have to pay workshop rates.

However if you a buying a good bike from a good LBS you'll find they'll disassemble the bike, chase and face the head tube, bottom bracket and disc tabs as part of the sale. They'll also make any upgrades that you've asked for, either purchased from them or from a different reseller.

If you're purchasing the parts from them on a new bike you should expect a discounted workshop rate. If your bring the parts you shop be expecting to pay premium workshop rates.

There's no set rule of thumb. However as always ensure you have a good relationship with your LBS and they'll look after you and your bike.


Road bike frame sizing I found an old racing road bike with a 50 cm frame. I would like to build it out and use it, but I am concerned it may be too small for me. I'm 5' 7.5" and I think I should be riding a 54 cm frame, but I'm not sure. Would that 4 cm difference be an issue?

I'd say "proceed with caution." The main question is whether you can get your contact points where you need them. And you probably can, but there may be compromises.

A smaller main triangle, ridden by someone with bigger feet, will increase the likelihood of toe overlap.
You'll obviously need to jack up the seatpost, and if you're past the limit line, you may need to get a new seatpost.
You may need to put a longer stem on the bike in order to get the right "reach," and this can have consequences for handling. You'll probably want to put on a stem that has a fair amount of rise, to make of for the frame's smaller "stack." Otherwise you'll either need very good hip and torso flexibility or a willingness to ride with discomfort.

Also, for whatever it's worth, small bikes (such as 50 cm) often have innate geometry compromises in order to fit the frame around 700C wheels.


Best way to sell cheap/damaged bike I have an old cruiser bike that I paid $100 for. The tire popped and the other has a flat but other than that it's ridable. Any way I can sell it? And if so, best website/company to sell it to?

I would put a note on the local message board, like the one in the school or the local supermarket, or the online version like Craiglist.
Most likely you will not get anything if people have to pay for transport, selling really local might be the best option.

But fixing the tires and cleaning it up might double the money you can get.

An other option is to keep it for when you can get a discount on a new bike on handing in an old one. Not sure that one comes around when you have a bike to get off your hands, but when there is one it will bring more for your bike than any private sale of an old bike.


What is a nipple driver and would I use one to replace a broken spoke? I have not yet built a wheel (or even replaced a broken spoke), so it's not quite clear to me what a nipple driver is. I also didn't find any reference on Sheldon Brown's Wheelbuilding page.

What is a nipple driver and how is it used? Is it a necessity or a convenience? Would I use one when replacing a broken spoke?

Wanted to add some photos of nipple drivers to augment @mikes's answer. Some are hex-shaft drill mounted drivers (top), some have straight screwdriver handles, others have offset handles to speed wheel building (bottom). They're handy for building up wheels quickly, but you need a proper spoke wrench for truing.


Upgrading cassette to give bigger bottom gear On e.g. a Giant Stance, can the lowest gear on the cassette be upgraded to a higher tooth count just by only changing that cog?

It seems the Giant Stance is equipped with Shimano Alivio. That's a fairly low-end groupset and I'm fairly sure you can't replace the cogs one-by-one. In any case, a whole new cassette is only about $20–25.


Are Merrell Barefoot shoes suitable for bike touring? These are the specific shoes: http://www.merrell.com/US/en-US/Product.mvc.aspx/22876M/0/Mens/Barefoot-True-Glove?dimensions=0

I'm going on a 210 mile bike trip this weekend and am looking for a new pair of shoes. Would these be appropriate for touring?

I own a pair of these shoes, and while they are good for "barefoot" style running. I wouldn't want to bike with them except in an emergency. They are very flexible, with a thin sole that you can feel everything through. As such, I would say that they are definitely not fit for touring.


My e-bike wiring is damaged and I don't know where to begin I was given a bike with an electric rear hub. I'm mechanically inclined but I've never had the opportunity to tinker with one of these. I'm fairly experienced with AC and DC electronics as well.
If anyone could help with where to start, I'd appreciate any advice or direction at all.
Thank-you...

First thing to do is check all the parts are present.  Without knowing your specific bike, you will probably have

A bike - thing with two wheels, etc.
Built into the bike will be a motor, probably in the middle of one wheel, but some designs have the motor between the pedals.  Rarely, some use a rubbing roller to push the wheel, but these are uncommon.
Battery - it should be fairly obvious.
Charger - lack of a charger is a strong indicator that the bike might be stolen.
Optional head unit / control panel - If the bike has one, it will likely be on the handlebars, and have some buttons and possibly a display or at least some LEDs for charge remaining.

Either in the battery pack or in the head unit will be a DC to AC converter.  Many ebikes have a 24 or 36 volt DC battery, but the motor itself is probably an AC unit for efficiency.

If you're looking at resistances, expect megaohms across the motor, and that it has 3 or 4 wires going to it.   You can't just connect the battery to the motor and have it go.

Make sure the battery is charged fully, then connect it, and turn on the bike.  You may need a key or card to do this, and lack of this is another indicator of a stolen bike.

When it starts, read the display, look at the LEDs, listen for beeps, and any bad messages should be referenced with the manufacturer's info.  This will be unique to the system, not necessarily the bike brand.

Modern ebikes tend to be "pedelec" meaning they give the rider an assist when pedalling motion is detected.  Older bikes tend to be throttle based, where you have a rheostat or a simple button for "add power"   Buttons are easy to troubleshoot, sensors are much less straightforward.

Other than that, its all getting very specific to your bike's electric system.  More details could help.


Will the Garmin Edge Touring store an in progress ride if power is lost? A rider is on a long ride, using a Garmin Edge Touring GPS unit and takes a break. If they wish to save battery on the Garmin, can they power it off and continue the same ride later?

I believe the Edge Touring is the same as the 810, with some features turned off.

Yes

A comment below made me wonder could a planned turn off be different to a random turn off like my original answer below.

So a quick test this morning and...
if you turn it off through the button on the side when you turn it back on you will have the Discard and Save option.
Press home, navigate to the trip screen again and your ride is ready to resume, just press the start button again.

If the Garmin decides to turn itself off though the data stored before that is lost.

Old answer... Proved to be incorrect

Not without some manual steps

You will need to manually stop the ride by pressing the start/stop button, then save the ride from the options presented, before turning of the Garmin.

Then turn the Garmin back on before riding off.

You will then be able to stitch the GPS files together to make one continuous journey if you don't want your ride broken into multiple sections

If the power turns off mid ride that section of the ride is lost.

I know this because my Touring turned itself off a few weeks ago mid ride and I lost the first 5km of my ride.


What tyre characteristics should I look for in a commuting tire? I am living in London, but moving to a suburb where my commute would take me through a park. Being rainy England, the track can get quite muddy and my current tyres don't seem to be suitable. What features should I look for in a tire for this purpose? The bike in question is am aluminum Trek Checkpoint. I currently have 32mm Continental Gator Hardshell tires, which are slick tires with puncture protection.

Generally, wide tires have lower rolling resistance than narrow ones, and they will be more comfortable due to cushioning. Hence, there's an argument you could go all the way up to a 45mm tire, the maximum I think your bike will clear.

For performance-oriented road riders, aerodynamic considerations might come into play, but these are probably irrelevant for you.

If you’re running tubeless for the flat protection benefits, that may be an additional argument for a wider tire. We know that tubeless tires don’t work as well on performance road bikes as they do on mountain or gravel bikes. This is likely because of high pressure and relatively small volume. A punctured 25-28mm road tire at 70-90 PSI deflates very fast. A 40mm gravel tire at 30 PSI deflates more slowly. I have a hunch that if you want to run tubeless, wider is better, all else equal.

If you want to run mudguards (aka fenders), you may need to limit the size of the tires you fit. It's best to maintain adequate clearance between the fender and tire. If there is too little clearance, you can get a branch sucked between the tire and the fender, and this can break the fender. I don't believe there are any other practical tradeoffs in going to a wider tire. You'll increase your coefficient of aerodynamic drag, but this is probably of little consequence here. I didn't see if Trek's stated tire clearance is 45mm with fenders or without; I suspect the latter. If so, then I suspect 38-40mm tires will fit and still provide a very nice ride.


How do I know if it's worth restoring my bike? I found myself in need of a bike, but buying a new one is out of the question. So two possibilities remain:

buy a used one for a low price;
fix one of my old bikes.

But here comes another problem (and my question): how old is too old? I mean, apart from comparing the price, how do I know that fixing a bike is just a waste of time and money because it's simply too old?

What should I consider for changing my choice from "fix it" to "buy it"? Rust? Other things?

I volunteer at a community bike shop. We take old donated bikes and fix them up for sale, so I have a lot of experience with this exact dilemma. Here are a few reasons why I will stop working on a bike I am refurbishing:

Frame has worse than just surface rust: i.e. extensive pitting and / or holes.
Seized parts, especially if they need replacing. Sometimes a seized seatpost isn't so bad, as long as the bike is sold along with that information. However if the bottom bracket needs service and can't be removed, the frame is scrap. The same goes for quill stems that can't be removed, locking the fork into the frame.
Damaged threads. If it's not possible to rethread an interface that has been wrecked (e.g. cross threaded), scrap the frame.
Bent or cracked tubing. The odd dent is fine, but if a bike has obviously been bent in an accident I scrap the frame. Same goes for tubes with any cracks in them, even if it's fixable. Obviously any carbon frame with cracks is worthless.

I'd also add that the original quality of the bike plays into these determinations as well. I will spend a lot less time working on the seized seatpost of an old BSO.

I'll also point out that a lot of these issues can be solved with extreme effort, e.g. replacing tubes in the frame. It just isn't worth it in this context and I suspect the same guideline applies for most folks tinkering at home.


Is Specialized brain something unique or are its variations common? I am looking into getting a full suspension mountain bike. Specialized touts their brain system and I'm wondering if is this some unique technology that they have or are at least more advanced at making than other manufacturers? Or is it that inertial systems like this commonplace and "brain" is a case of good marketing? I'm looking at bikes around 2000 USD (possibly a cheaper Trek), do I need to make extra sure it has a similar system in place or is it a given in this range?

Inertial systems like the brain have been around for several decades, however, Specialized is probably to the first company to do them light (ish), mass produced and marketed.  The real question is not "how good is it?" (is does work), but "do you want/need it as a rider?"

I worked at a Specialized shop for sometime, and opinions on the brain seem to vary.  I know several riders that swear by them as one of the most awesome things ever, but also people didn't feel like it was needed or just couldn't tell the difference.  Personally, I always felt like they added a bit of efficiency, but since I rarely rode trails that benefited from it, and that I didn't MTB race, it wasn't really necessary for me.

The brains "automagikness" isn't necessarily standard in the price range, however easily adjustable suspension is.  In that range you'll find most suspension has some sort of quick adjustment knob or switch to vary the performance of the shock.  Such systems will likely weigh less, but require rider input.

It should be all about your riding style.  If the trails you frequent don't require suspension adjustment "on the fly", the brain will likely just be extra weight.  If they do, but you don't want to deal with flipping a knob or switch, and you like the way it feels, it may be for you.


Are cross brake levers with compact drop bar redundant? I currently have traditional drop bars and cross (interrupter) brake levers. I like the interrupters and use them a lot.

But I'm going to get a compact drop bar (FSA Omega Compact bar on order), and in trying to envision this new setup, it seems the interrupters might be less useful with compact bars because my hands, even on the cross bar, will be closer to the (regular) brakes.  Plus the "cockpit" area, being more compact with compact bars, might be overly cluttered with interrupters in there. Plus with a compact bar I suspect I'll have my hands on the cross bar less of the time.

All in all it seems interrupter brakes are less desirable on a compact drop bar than they are on a traditional drop bar.

Does anyone use interrupter brake levers on a compact bar?

Generally a compact bar refers to the drops, not the width of the bar. The drop levers and interrupter levers will most likely be nearly the same distance apart. Your preference is all that matters.


Pedals rotate backwards when I move the (rear) wheel in reverse direction I recently bought a bicycle and am new to biking. So I decided to try it out on an inclined part of the road near my home. as I descended on the incline just after travelling a few metres I heard a clink sound from the chain system. Naturally I braked at once and decided to check but I could not find anything visibly wrong.

However as I headed back home to further check for something I noticed that whenever I move my rear wheel opposite to its usual direction of motion the pedals started to move opposite to their natural direction of rotation. How can I fix this?

There is nothing to fix, most of the hub works like that. It is normal behaviour implied by the hub internal design.
If you really want your pedal not to rotate when moving bike backwards, you can move to single speed, coaster brake, traditional Velosteel hub. Personally strongly dissuade.

edit after comment:

This photo should explain why wheel is not conjugated with chain, while no force is applied on the pedal. At the right side we can see rollers in its housing. It slides back and forth.

This photo is even better. 2 clutches. Moving forward pushes right against hub housing, conjugating sprocket with hub housing.
Moving backwards pushes left against coaster brake pad. Pads does not rotate because of being engaged with brake arm attached to frame. Because of friction hub housing start to conjugate with brake pad.

No force applied - everything disengaged.


What is the best approach to an again and again wobbling rear wheel For the last ten years, I have been riding a mountain bike (Specialized/Rockhopper), and often rather wildly, through rough terrain (roots, jumps, ruts). I am around 110 kg (240 pounds).
As a consequence, my back wheel often starts to wobble after some dozen rides, typically coming with the loss of one or more spokes. My cure so far was to bring it in the shop, and get the spokes replaced, and the wheel was true again. There are rarely issues with the front wheel, but it happened too.

However, in the recent two years, I have only ridden on pavement (roads and bike trails), and it still happens a lot now. I have the feeling that the back wheel is just beyond its life, but I'm not sure, and I really don't have the knowledge if this makes even sense.

The question is, what is the best/right thing to do now:

I can keep going to the shop every other month, and get the rear wheel trued-up. Costly in the long term, but works.
I can ask them to replace the rear wheel. A lot more cost, as the cassette needs to be transferred, and this would open a can of worms, the cassette is over ten years old and maybe should be replaced too, and when doing this, the derailleur, the chain, and the front sprockets also should be replaced, so I'm quickly nearing the price of a new bike. It might still be the best option, though.
I can buy spokes and a spoke key - should be cheap - and learn to fix that myself. That is at the moment my favorite idea, but I am not sure it solves the issue.
I can remove all spokes, to see the true form of the rear wheel (which is probably badly bend). Then I bend it back to about straight (or replace it), and add all spokes back in. I don't know if that approach makes any sense; it sounds like a lot of effort.
I can toss it and buy a new bike

I am looking for someone experienced with such repairs, who is not interested to make the most money off me, to tell me what is the best approach. What makes sense?

Unless the cost of a new wheel that's suitable for you plus any other repairs the bike might need is greater than what the bike is worth to you, than the answer by far is get a new wheel.

Folks in your weight range who ride a lot tend to need an especially strong and reliable aftermarket wheel. The stock advice is to get a handbuilt one. The reason for this is that a good handbuilt wheel has a number of processes done to it that make spoke breakage and loosening much less of a factor, to the point of never occurring if everything goes right. But that sort of wheel is usually around twice the price of a replacement wheel that at least has the fundamentals covered for what you need (strong rim). A conscientious mechanic installing that sort of wheel on your bike will see that you would be best served by handbuilt and be able to do some of those steps on a cheaper machine-built wheel without adding a bunch of time. (The big example being making sure the spoke tensions are high and balanced, and stress-relieving them).

The cost of handbuilt wheels can be considerable, but another way of looking at them is they're not really optional if you ride enough and are heavy. Otherwise one is liable to spend several times their cost getting the stock one fixed, as you've experienced.

Swapping the cassette on to a new wheel in and of itself and adjusting the rear derailleur if needed is easy and will work as well as it did before, more or less regardless of drivetrain wear. If you need a new drivetrain and feel it may not all be worth it, that's a separate consideration. It is true that new rear wheel time can be the moment where a bike is deemed not worth fixing.


Is there a way to convert from a dropout frame / fork to a quick release / thru axle? just really want to know if I can, because I am working on a project bike and can't find good parts for a dropout frame.

Short of cutting off the dropouts and welding/brazing/bonding on through-axle fixtures, no, you can't convert between them.


How to repair shifter housing I have shifter with damaged housing. It shifts well, but I guess if housing is not repaied, rain and elements will quickly put an end to it. Which material would be suitable to fix this hole? Epoxy glues? Maybe ones with metal filler? Are there some sensitive parts in the damaged area that I should be carefull not to glue?

Seems like you have two options. I'm not sure this is your exact model but the broken piece should just unscrew.

Unscrew what's left and epoxy it together apart from the internal workings.
Buy a replacement cover. I couldn't find any online shops selling replacement covers, but a call to Shimano* will probably net you the exact piece you need. You'll need to know the model number which should be displayed somewhere and look like SL-xxxx. I can't imagine a new one will be more than $20.

*Shimano American Corp. (949) 951-5003


What are the differences between Columbus Tubings? I'm just wondering why there are seven kinds of tube sets by Columbus (or Reynolds). There's XCr, Spirit, Life, Zona, Max, SL, and Cromor. I recently had a frame made using the Cromor tubeset; mainly because it was the cheapest set they have. Now I'm wondering what really is the difference between the other sets and why they cost more.

I read the product catalogue, it's mostly about the material used and mechanical characteristics, which I'm not really familiar with. Could someone explain the differences, as well as pros and cons, in layman's terms?

The Bicycle Info Project has a nice page at http://www.equusbicycle.com/bike/columbus/columbuschart.htm that describes the different Columbus tubesets in layman terms.  The following is a sampling of what is on the site.  The information gets even more specific relating characteristics to particular tubes (e.g. top tube, seat tube, chainstays, etc..)


52/36 Chainrings for Ultegra 6750 crankset I have standard compact (50/34) crankset. It seems to be to small for finish on flat stages. I am going to replace chainrings for semi-compact.
I've found that absoluteBlack offers products for older crankset like mine
Premium Oval 110 4bolts

Do you know if there are any other chainrings (52/36) for 110BCD 5 bolt which fits Ultegra 6750 ?

Yes, there are. Any 110BCD 5 bolt chainring except Campagnolo will fit. If you want to keep the smooth appearance with hidden chainring bolts, at least Specialites TA and Stronglight make compatible chainrings at wide range of sizes.


Cleaning and lubing bicycle chain with diesel For last 3 weeks I am using diesel for my cleaning and lubing my bicycle chain, so far I am not facing any problems.

Should I continue this or am I damaging my chains ?

Has anyone else using this method ?

3 weeks isn't likely enough for you to damage the chain noticeably (rattling sounds and all that jazz) unless you're putting particularly heavy mileage.

This isn't something I'd recommend doing; diesel fuel doesn't have the right lubricating properties for a bicycle chain. It's also not the most pleasant stuff to be around.

Diesel will act as a degreaser which will clean the chain, but this is against most chain manufacturer's recommendations to begin with (which I've outlined here).

I'd suggest following the directions of the manufacturer and using a bicycle specific chain lube (or 3-in-1 if you want to save money), and a damp cloth to periodically wipe down the chain after riding and re-lubricating. I do own a chain washing machine, but it hasn't been used in quite a while.


What do I do when I don't trust my LBS to repair a problem they caused? I have a Sturmey Archer 3-speed hub on an ex-single speed. I got a flat on my way to work and couldn't ride any more. So I jumped on the train and took it to the bike shop near work (the shop who fitted the hub was too far from my work) to get them to fit a new tyre and tube. They've generally seemed pretty knowledgeable and competent when I've used them in the past.

When I picked it up, they'd removed the changing cable and shaft (sorry, I don't know what this is called) that triggers the gear change from the hub and when I pointed it out they didn't even think that was a problem. So I assume they aren't exactly familiar with Sturmey Archer hubs.

Unfortunately when they re-fitted the axle nuts they cross threaded it. So the nut was completely stripped and now I can't properly thread a new nut onto the axle, as the thread on the axle is also damaged.

My first thought is to take it back and get them to fix it. But if the fix necessitates a new axle, I don't trust them to do the work. So I guess I should ask them to pay for me to return the hub to the shop I bought it from so they can repair it, but I doubt they'll agree to that.

What is a reasonable expectation? How should I proceed from here?

First thing always is to take it back to that LBS and talk to the manager or owner. At the very least that way you know that they know you're unhappy. Probably they will offer to fix the problem for you (or get one of their mechanics to do it). From working in a bike shop we always took those return/re-repair jobs quite seriously, because one angry ex-customer will tell 100 people but a happy customer might tell 2.

Getting them to pay a competitor to fix your bike is harder, especially if you want to take it there yourself and get reimbursed. Generally they will get a better price than you will just because they're another bike shop, so it's better for them to send the job through. Which they will do if they can't do the work themselves. Small shops often do this with stuff like suspension rebuilds that require specialised tools and knowledge. But for a simple wheel install? Unlikely.

(edit)But now that it's an axle replacement you might have more luck. This is likely to be tricky anyway, since axles for some older SA hubs aren't made any more (AFAIK), so it might come down to who actually has the part. Your best bet might be to find a shop that does deal with older hubs and get a quote from them. Tell them you're going g back to the first shop, so they don't write "replace type 253a axle in SA 3xHD hub" on the quote (because that would let any monkey buy one on eBay). That way you're just doing work you'd have to do anyway, and you might get the actual repair done free. At the very least you have some idea of how hard it's going to be to do the work and what it will cost, for when you're negotiating with original shop.

The question for the shop is whether you be significantly less annoyed if they do this than if they just offer to fix it themselves, and how will that story play out to people you tell it to? Unless you lie you're going to be telling potential customers "they screwed up, and when I took it back they offered to fix it but I wanted to have them pay another shop to fix it and they wouldn't do that". Not something that would put me off using that shop.


Campagnolo Cambio Corsa primitive derailleur -- can it be recreated? Does anyone make this sort of system and sell it today, or is my only option looking for someone selling theirs? I've googled whether similar systems are being made today but found nothing to my liking. Are there any new versions of this?

This system, the Campagnolo Cambio Corsa, or race shifter was introduced in 1946 and superseded in 1949 by the Paris Roubaix which used only one lever, vs. two and again in 1951 by the Gran Sport parallelogram derailleur, which slightly modified is still state of the art. The Cambio Corsa was probably only made for three years.

It is still possible to buy these parts, complete systems or bikes with these parts on sites like eBay. Keep in mind that the Cambio Corsa and Paris Roubaix systems require special toothed rear dropouts and can't be used on just any bike.

Even at vintage events like the Eroica it's rare to see them as the gearing is not suited to the routes.


Giant Overdrive 2 fork replacement I have a 2014 Giant Trance with an Overdrive 2 tapered steerer (1-1/2 - 1-1/4). As we know, the standard tapered steerer is 1-1/2 - 1-1/8 inch. I want to replace my OEM fork (Fox 32 Float Evolution CTD 140) with a more advanced Fox or RS. Is it possible to fit the bike with a standard steerer? I know that it would mean changing all the front end of the bike (fork, headset, stem) which I am prepared to do. Is there a headset to accommodate my frame and new fork. Would a standard tapered integrated headset do? Has anyone have an OD2 Giant bike here that have done the same exercise? This bike is problematic!

You can just buy a standard tapered headset. Or if you can firnt it, only the upper assembly for 1 1/8". Giant uses the same diamete for their 1 1/8" and 1 1/4" headsets as it says here: http://www.pinkbike.com/news/Giant-OverDrive-2-Steerer-tube-sizing-2011.html.

Another solution I can think of is to turn a spacer yourself (or have it done by someone) to work as an inner race for the bearing. It's more demanding (since you would have to turn both the spacer and a cap), but could probably work out a bit cheaper than the entire headset.


gears overshifting issue As I have explained in my previous post here I have changed my rear shifter cable and housing. But I'm still having issues with shifting gears smoothly.

It overshifts at particular gear combinations or doesn't shift into the right gear. For eg., when I'm shifting to a lower gear from 5 to 4 it skips 4 and goes to 3 straight off. But this is not a problem when upshifting, meaning it shifts from 3 to 4 correctly and 4 - 5 correctly. I tried tuning/indexing gears but if I fix that particular issue above, it stops shifting into from 7 to 8 or some other gear combination stops working correctly.

As for the bike it's a GIANT Cypress which I bought used off online. It's got shimano acera gears. I have cleaned and lubed the drivetrain but shifting doesn't Improve. I have just attached a pic of the rear cogs just for you to see the condition of it, if that helps the least.

could this be a problem due to the chain? or derailleurs? or something else? Anything I should try before replacing anything or taking it to a bike shop?

Since everything else is working, this is when I suspect hanger alignment. Where the rear derailleur bolts on to the bike, just under the quick release/axle, is a relatively fragile piece of metal. They get bent if the derailleur is bumped hard, and for that reason are often replaceable parts.

The problem is sufficiently common that there's a tool made specifically to fix it:

Those are about $AUS40 to buy, but you're not going to use it very often. Probably once. But your local bike shop will have one, and it's probably less than the cost of the tool to get them to look at the problem. Or you can buy the tool and look up how to use it (it's not hard). Without the tool you're very unlikely to improve things by trying to fake it.


Converting bike from rim brakes to disc brakes I just bought a used 2009 Kona Dew and it comes with regular rim brakes. I'm perfectly happy with them so far, but have been wondering if disc brakes would come handy when it rains.

What is involved in converting a bike from rim brakes to disc brakes (mechanical or hydraulic)?

Is this something that is feasible, or am I better off buying another bike that already has disc brakes?

Your frame and fork already have disc tabs, which is the first step.  The second is a disc wheelset, which it does not appear that the stock wheels are.  Disc hubs come in two varieties: the common six-bolt ISO and the proprietary Shimano Centerlock, the former are identifiable by a large six-bolt-hole protrusion on the left (non-drive) side of the bike.  The latter have a rubber cover over a smaller splined mount.

Once a new wheelset is selected, you'll need a set of calipers and disc rotors.  The Avid BB7 is a popular mechanical disc caliper, and will work with your existing linear-pull brake levers.

Installation is fairly straightforward, but since it involves braking it's worth involving a professional if you're at all in doubt of your mechanical aptitude.  The disc rotors bolt to the wheel, the calipers to the frame.  The old v-brakes are removed.  New cables and housing are routed from the levers to the calipers and the calipers are adjusted.

Cost-wise, if you're happy with the bicycle otherwise it's not a poor investment - good wheels and brakes can be moved to future bikes if you later decide to upgrade the frame.  The ideal time would be to consider when the wheels already need to be replaced due to wear, since the new wheelset will represent the majority of the upgrade cost.


Software for time-trial race I'm looking for a piece of software to conduct a local time-trial race. There will be some 50 riders: large enough to make the job of preparing race results with bare pen and paper rather hard and time consuming, but too small to use full-fledged race chips systems.

Riders are going to start with one minute interval and on the finishing line there will be a man announcing time to the operator. So the operator will just have to enter the time of the rider to the program. The program should be able to produce the table of results on the fly as the riders cross the line.

I understand that creating this kind of software is not that hard, but I was just hoping there are readily available freeware solutions that I could use for my event. Please let me know if you ever heard of any.

This will run in python (only 3.X, not 2.7), a free to install programming language. Simply save the following as a file ending .py - e.g. timetrials.py. Then open IDLE3 (start menu), and open the file (Ctrl+O). Finally, press F5 to start it.

import datetime
from operator import itemgetter

def get_int_input(prompt, min_=0, max_=None):
    """Get a valid integer input."""
    while True:
        try:
            i = int(input(prompt))
        except ValueError:
            print("Please enter an integer.")
        else:
            if min_ is not None and i < min_:
                print("Must be at least {0}.".format(min_))
                continue
            elif max_ is not None and i > max_:
                print("Must be at most {0}.".format(max_))
                continue
            return i

def get_time():
    """"Get a time input as a datetime.time object."""
    h = get_int_input("Hours (0-23): ", max_=23)
    m = get_int_input("Minutes (0-59): ", max_=59)
    s = get_int_input("Seconds (0-59): ", max_=59)
    ms = get_int_input("Milliseconds (0-999): ", max_=999)
    return datetime.time(h, m, s, ms*1000)

def get_results(competitors):
    """Get a dict of finishing times for all competitors."""
    results = {}
    for _ in range(competitors):
        while True:
            competitor = get_int_input("Enter competitor number: ", min_=1, max_=competitors+1)
            if competitor not in results:
                results[competitor] = get_time()
                break
            print("Time already entered.")
        print_results(results)
    return results

def print_results(results):
    """Display the race results in a table, fastest first."""
    linet = '┌' + "─" * 12 + '┬' + '─' * 17 + '┐'
    linec = '├' + "─" * 12 + '┼' + '─' * 17 + '┤'
    lineb = '└' + "─" * 12 + '┴' + '─' * 17 + '┘'
    print(linet)
    print("│ Competitor │ Time (H:M:S)    │")
    for n, t in sorted(results.items(), key=itemgetter(1)):
        print(linec)
        print("│ {0:<10d} │ {1!s:<15} │".format(n, t))
    print(lineb)

def race():
    """Handle race times for a user-specified number of competitors."""
    n = get_int_input("Enter number of competitors (2-): ", min_=2)
    results = get_results(n)

if __name__ == "__main__":
    race()

When everyone has finished, it will look something like this:

┌──────────────┬───────────────┐
│  Con Num     │ Time H:M:S    │
├──────────────┼───────────────┤
│  1           │ 5:4:3.2       │
├──────────────┼───────────────┤
│  2           │ 8:7:6.5       │
├──────────────┼───────────────┤
│  3           │ 2:2:2.2       │
└──────────────┴───────────────┘


Is throttle-only possible for mid-drive? Suppose I want an electric bike with throttle. Is mid-drive (crank based) even an option? I got impression that mid-drive means pedal assist only (PAS).

While I'm not aware of any examples of a throttle operated mid-drive, it is certainly possible. With a regular bicycle crankset, a mid-drive motor will push the crankset around, transferring the power into the chain through the chainrings to the chain. This involves causing the crankarms to spin while in use, making it Pedal-Assist only for any practical use.

What you would need is a crankset like the one in several Specialized ebike models. These have a freewheel-like release in them. This means that when you pedal backwards, the chainrings do not spin backwards, but when pedalled forwards, the crankset mechanism engages and turn the chainrings forward. With a crankset like this, you could have a mid-drive ebike which could be operated by Pedal-Assist or by throttle.


Identify a replacement shimano rear derailleur I have managed to bend the rear derailleur on my gt palomar, the gear was not clicking through so I moved it through the gears set off and heard it crunch.  The whole arm is bent.
It appears to be a shimano 7 sis dr of some kind. Can someone advise of the correct replacement I can buy. Would a shimano tourney or Altus be the right thing?
Many thanks for your help
[![enter image description here][2]][2]
[2]: https://i.stack.imgur.com/ZuOUz.jpg![enter image description here](https://i.stack.imgur.com/VaBg0.jpg)

As the picture shows the shifter, the derailleur is the bit at the other end, I presume its the shifter that has broken.
Any 7 speed shifter will work. this is a combined shifter so you will need a combined (with brake lever) shifter or you could choose to install a seperate shifter and brake lever.
You will almost certainly need (and be a lot easier) to get new brake and shifter inner cables to install the new levers. The cable installed though the shifter and brake lever then threads back to the derailleur or brakes. Reusing an old cable, is almost always an exercise in frustration followed by installing a new cable anyway.  I would install new outers as well when doing a job like this just to be sure they are not a problem.   Levers themselves are incredibly reliable, so its possible that the rear derailleur is part of the problem.
Brakes have two cable pull lengths, make sure the lever you purchase matches the brakes on the bike. In this case as the lever says V Brake so any V Brake compatible lever will work.
We don't do product recommendations, but something like ST-EF500-7R2A would be good.  If cost is a consideration have a look to see if you have a local bike coop.


How to prevent accidental unclipping while cornering? I have less than 10 hours on SPD pedals. Unclipping is becoming more and more intuitive (I no longer fall to the side when stopping at a traffic light). While it still intimidates me to jump with clips, cornering needs to be done.

When I approach a corner, regardless if on asphalt or on the trail, I look into the exit, rotate my head, chest and hips towards the exit, stay centered on the bike, but tilt the bike.

My concern is that by rotating my hips I will accidentally unclip, dropping my foot to the ground in the most dangerous part of the turn. Do I need to worry about this, and if so, how to prevent it?

PS: My pedals are mixed SPD/plaform pedals and the shoes are Cube AM.

Don't worry about things that haven't happened.

Most people new to clipless are worried about the exact opposite. "Will I be able to unclip if things go south in a turn?"

Eventually you will get to the point where clipping in/out is completely unconscious.

Having said all that, if unclipping when you don't want to really becomes a problem, look into getting a setup with more "float". Float is the angle at which the cleat releases.
SPD cleats come in different versions with different float.

You can also get pedal with more float that standard SPD's.


How do I determine my Campy cage size? I have a Campagnolo Chorus 9-speed rear derailleur. I am trying to determine the largest cassette I can use. The main question I have is how do I determine what size cage I have. It is not a new derailleur. I have 50-36 chain rings and currently a 23-11 cassette. Would like to go a little bigger on the largest cassette cog if possible.

There are two parts to this - the cage length is the distance between the two jockey gears in the rear derailleur, and this limits how many links of chain it can take up while maintaining tension.  Longer cages (like MTB ones) could do 11-42 so a difference of 31 half-links.

Road bikes tend to be narrower, so a short cage might only take up 11-2x.  There are many in-between lengths.

So change to the bottom gear, and look to see if your lower jockey wheel could move further forward.
Then consider if the chain was a couple links longer and you're in a small/small combo, would the chain touch itself?

The second part of your question is whether there is space for a larger big cog on the back.

The eyeball technique would be to put the bike into its bottom gear, so 36/23.   Then look to see how much space is left between the top jockey wheel and the largest cog.  If the bike came with 23, then 25 is likely to work, and you might be able to get up to a 28 in there.

Otherwise you have to change the rear derailleur too, which is another cost.


140mm rear rotor for bike packing Currently my bike has cable actuated disc brakes, which I will upgrade to Ultegra 8070 callipers and RT-800 Ice Tech rotors.  I use the bike for road, some gravel and bike packing.
The current rotors are 160mm front and rear.  The rear rotor is a pain when I remove my rear wheel: due to the rear derailleur I need to move the wheel slightly forward to remove it and I end up scratching my frame with the rotor (the non-drive chain stay, even when I am careful). After 2 years of doing this, the frame has lost quiet a bit of paint...
Because of this I am thinking to put a 140mm rotor in the rear, rather than replace it with another 160mm rotor.  But I am nervous about this for bike packing use.  I weigh about 80KG and worst case my gear would be about 10KG if I would ride with a pannier.
Obviously I don't want to get in a tricky situation by overheating my brakes, but I am also fed up with the scratching and want to apply some clear coat on the exposed aluminium.
Q: Should I be fine with 140mm rotors on a (medium mountainous) bike packing trip given my weight?

I doubt it will make a big difference. A majority of the braking should be coming from the front anyway.  Most MTB's run a smaller rear rotor than front with no problems.

There are a couple of things you can do will help if going to a smaller disc. If brakes are DOT fluid, bleed with a DOT 5.1 to give higher temperature tolerance (although being Shimano I expect the brake are mineral oil) and run metallic pads as these resist brake fade better than organics.

The weight you are taking is not high - many riders of bikes would weight in excess of 100kg. Also when loaded for bike packing I would be surprised if you ride as aggressively as normal.

Ultimately it comes down to you braking style. If you are heavy on you brakes, drag the rear brake and generally have little care for heat management in them, don't do it.  If you have good braking technique and are not riding aggressively you will not have a problem.


How to bike with less stress on the calves I have a condition called functional PAES, which is caused by the calf muscles compressing the popliteal artery. My doctor recommended activities that would not put much stress on the calves, and while biking may not be ideal, it is much better than walking or running. Do you know tips or techniques to would make me depend less on calf muscles when riding?

The two changes I have made so far are:

Adjusting the seat to be lower than it should be.
Pedaling with the instep of the foot, never with the sole.

Do you agree that those changes will reduce the stress on the calves (even if they make my pedaling more inefficient)?

p.s. PAES is a very rare condition, and it is very hard for me to find support in the real-world in the country where I live, so I have no other choice than figuring out by myself how to live with it. It is definitely possible to change the lifestyle to handle functional PAES, see this ballet dancer case study for example.

If you are using clipless pedals, then mid-sole cleat positioning is sometimes recommended to triathletes specifically to reduce load on the calves (eg).

I haven't used it myself, but it might be worth a look.

Here is another question discussing mid-foot cleat positioning (with no super clear consensus)


Is this wheel built incorrectly? I am swapping around some hubs, and this means rebuilding two wheels, a 20" and a 26", both 36 spoke and both were done standard cross-3 lacing.

Here's how the 26" wheel hub looks after assembly.

Notice the two marked spokes?  They're both trailing spokes in this case, each go through the holes opposite ways.  That is, one is inside to outside, and the other is outside to inside.

Is this right or wrong?  And if its wrong, how wrong is it ?

Update - this wheel has been working perfectly for the last four years, and has done a number of MTB endurance rides without issue.

It's a little bit wrong in that it has zero upside and one potential downside, but that downside is unlikely to ever be relevant.

Trailing spokes straighten a little temporarily under drive load, and this causes the spokes to essentially be pushing on each other a little at the cross. On a wheel laced like this (there's no agreed upon term for it but let's call it "asymmetric"), the idea exists that the forces from the spokes pushing on each other in this way add together and can cause the rim to get pulled over to one side slightly in use, whereas with mirror-image lacing the forces would cancel each other out, or come closer to it.

This is probably a real thing that happens, but it doesn't really make any difference I've ever seen, and we're talking about a very small amount of movement in the rim. If there were consequences, it would probably be on a bike with tight tire clearance. Some wheel manufacturers make all their wheels this way, because it can save steps and/or simplify their procedures.

The more potentially consequential side to rebuilding a wheel this way is that double-grooving the flanges increases the risk of flange failure and increases the amount of work you have to do to get the spokes bedded into the flanges. So barring situations where you're forced to use a different lacing pattern on the same hub, or where you're switching to a rim of different "handedness" than the old one (only really something you'll see if vintage parts are involved AFAIK), there is zero reason to not re-use the existing grooves. (Note that this is not to say that flange failure is at all likely from double-grooving a tangentially laced wheel, just that the odds of it happening go up.) If the wheel was built asymmetrically originally, it should usually be re-laced this way.


Should I use a gel saddle or not? My girlfriend have just bought a gel saddle for her hybrid bike. She does day trips with it (30-50 kms) and a bit of commuting. Some say this saddle is useless and she should buy bike trousers instead. What do you think?

Generally you will find, for getting started a gel seat may help.  As do padded shorts.

However, once you ride regularly, and build some muscle and tolerance around your sit bones, you will find it annoying.

So it is a good gateway drug to getting used to a saddle.  Generally people find that narrower and simpler seats are more comfortable, once you start riding regularly and build up your seat area.


I would like the suspension specs on my 2002 Rocky Mountain Element. Any help is appreciated I'm riding a 2002 Rocky Mountain Element.  It has a blown shock in the rear.  I would like to find the specs for replacement of the Fox Float R 2002 shock.  Any help is appreciated.

Via https://www.bikes.com/sites/default/files/2004_RMB_TECH_MANUAL_EN.pdf page 47

Shock size is 6.5" eye-eye, 1.5" stroke.

Note: Thats a 2004 spec so check the eye-to-eye length, if thats a match theres a high probability that the stroke length is the same.
Ebay/Amazon is your best bet for random shocks, you don't need to replace with a Fox. While OEM shocks are custom tuned for a given bike model I imagine you'd just prefer to be back on the trail so don't stress too much about an exact shock match.
The other alternative is to send the shock to a professional for a rebuild. The pro shock mechanics have access to almost anything via their channels.


Why does the chain tension vary as pedals are turned? I have a new single-speed bike (after purchase this year, it was unused in a garage for a few months), but as I turn the pedals, the tension in the chain varies noticeably.

What should I check, one-by-one, to find the source (and fix it)?

If not mitigated (I'm guessing it'll never be perfect), can it wear down the chain/sprokets faster? Cause any other issues?

More information, and bonus question:

I'm also having an issue that twice per a full pedal rotation, there is a click sound that seems to come from the bottom bracket. Not sure if related?

Possible causes:

There is "play" in the bottom bracket bearings, this could also explain the clicks. Usually this is quite noticeable, and you can check it by grabbing the crank-arm and trying to move it sideways. Usually this is not the cause for variable chain tension on singles;
The chainring is "eccentric", either because of haveing been tightened off-center, being manufactured off-center (some defect or poor quality), or damaged. The best way to check is to suspend the bike or turn it upside-down, then slowly spin the cranks do see if it looks off-center. If it is badly assembled, you can try to loosen the bolts and recenter it manually;
The sprocket might be off-center. This can be very subtle, but you can see the difference between the sprocket or the chainring being off-center depending on how many times per turn the chain reaches its tight spot, since the sprocket has a much smaller diameter;
The chain itself can be unevenly worn out, or be uneven from factory. This can happen with very cheap chains, and can cause even a combination of slight unevenness of chain, sprocket and chainring to create a somewhat "random" pattern of tightening and loosening of the chain as the bike rolls.

As for the consequences, I would say that the main problem would be to adjust the rear axle too tight, as this would cause excessive mechanical stress on the drivetrain, or to assemble it so loose that it falls off. Except if you ride fixed or coaster brake (when the lag while pedalling backwards would become a bit annoying), there is not much problem in letting it a bit more on the loose side (enough not to reach an overtight position).

Also, if you use good quality chains and replace the chain often, the rest of the drivetrain tends to "age well" while wearing, because the teeth tend to "even out" in the process. But if you use crappy chains, even good quality gears will suffer a lot more...

Hope this helps!


How do I calculate the spring weight rating for my bike? I have a home built bike design and the rear shock absorber that came with the part bottoms out so I want to get one that is more appropriate. But I have no idea how to calculate which one to buy as far as the tension of the spring is concerned.

At Amazon for example there are many from 550lbs to 1500lbs shocks. I don't want an immovable spring nor do I want another weakling so how do I calculate what shock to get?

ADDITIONAL INFO EDIT
I found this calculator
https://www.tftuned.com/spring-calculator
I put in 210lbs - shock stroke 1.5" - wheel travel 4.5" - 33%sag

I don't have a clue how to read these results.

From that spring calculator site  "The spring rate is the amount of force required to compress the spring one inch, and is measured in pounds."

Your current spring is rated at 550 pounds according to the label

Optional - to test it, put the spring somewhere you can measure the compression accurately, and load it with 55 pounds of weight.  It should compress 1/10 of an inch and then rebound to the original length.  Likewise it should extend 1/10 of an inch if you hang 55 pounds off it.

As long as you're not exceeding its elastic limits then the spring will rebound to its empty size (so says Hooke's Law)  Otherwise it will permanently deform, but that will take a lot of weight.

Based on the numbers in your question the answers from the calculator are:

Single Pivot / DW-Link

CCDB/5th(CVT)/Man(SPV)    764 lbs
Fox/RS/Maz (shims)       859 lbs

This is a single pivot suspension:

4 Bar / VPP

CCDB/5th(CVT)/Man(SPV)    840 lbs
Fox/RS/Maz (shims)      935 lbs

This is a pivoiting suspension:

The other titles are brands

CCDB is probably Cane Creek
5th CVT is probably Progressive Suspension Fifth Element
SPV is Manitou air shock
Fox is Fox Suspension
RS is RS Suspension
Maz escapes me sorry
Shims is one way of adjusting the spring, by adding more washer-like obstacles to compress the spring sooner.

Given your bike is slightly non-standard, at the end of the day you're going to have to take a guess.  If your bike has a see-saw pivot in the suspension, go higher or if its a straight squash then go lighter spring rate.

You could also consider the normal load you exert on the saddle when it bottoms out.  Then imagine half that weight, and extrapolate from there.


How did my headset get this way? I have a newish bike I bought second hand.  To the best of my knowledge, the headset has not been dismantled as it all looks original.  It's a threaded headset and a 1" fork steerer tube.  It looks awfully like this Ritchey headset apart from the Ritchey logos - but I'm pretty sure it came out of the same factory. https://www.chainreactioncycles.com/ritchey-logic-threaded-headset/rp-prod39820

It has never quite sat right - and pressing on the handlebars always made a slight squeaky sound.  I thought I'd have a go at dismantling it using the right 32mm wrench on the race.  The locknut came out no problem - I used the wrench to loosen it and then it came out just with my hand, so I know the steerer thread was fine.  But then I tried to take the race out, and man it was hard, I had to use the wrench with full force.  I managed to get it about 1/8" from the top before I stripped the nut on it.  And at that point, it looks like it's been cross threaded as the race doesn't quite sit parallel to the tube end.

So the question is how could this have arisen?  Is it possible the factory assembled a cross threaded race and just forced it all the way down to a point where it sorta passed quality control?  Or is something more sinister at play here and do I have an even bigger problem?  And as for any tips on how to get the race out?  I'm thinking of sawing through the nut itself but not sure if this will work.  Any ideas very welcome.

Thanks in advance.

Nathan's comment is solid -
Assuming Stephan removed the keyed washer when he took off the lock nut...

How did it get this way?
It's hard to say, here are some possibilities.

It may have been cross threaded from the factory. Seems like a long way to cross thread something - all the way from the top of the steerer tube to it's current   location and then back up to almost the top. Cross threading usually results in some thread damage that should be visible in the steerer tube threads.
A previous owner may have cross threaded it. Same observations as option 1.
I can't think of anything besides cross threading (and Nathan's suggestion)

How to fix it?
First, check Nathan's thought - look for a keyed washer sitting on top of the race nut. It's labeled "Washer" in the diagram below.

Assuming cross thread - since you are 1/8 of an inch from the top with a rounded nut I'd look for a tool that will like a large vice grip to clamp on to turn in the last little bit. Some penetrating lubrication might help.
I'm worried about cutting the race off. It's hard to imagine how you can cut it without damaging the steerer tube threads. If you use some kind of a small cut off saw, don't go all the way through, make a couple cuts and experiment with a chisel to remove a section of the race it might not damage the threads.
I've read of people having success using heat to remove stuck nuts. I've never had any luck with it.

Maybe someone else will have a better suggestion.

If the threads on the steerer tube are OK all you'll need is a new adjustable race.
If not, you may be able to clean up the threads with the right threading die.
If not, you'll need a new fork


Which new road bikes can have seat height 890mm or more? I'm looking for a new aero road bike. I'm a tall person. And from past experiences and from bike-fiting advices I need a seat height of around 890-895mm.
I checked Cannondale, BMC, Factor, Orbea. They don't have any model that can have that seat height.

Giant Propel can have it but currently it's not in stock and it'll be earliest next fall.

Canyon can also have, but after the recent seatpost drama, they don't have the stock and I'm not sure I want the Canyon bikes.

Trek Emonda/Madone can have it. But from past experiences, I do not want another Trek bike.

What other bike brands and models can have that seat height?

Sounds like you're searching for a carbon bike, but a steel bike might be more likely to be available in your size. The Surly straggler has a 620mm seat tube (62cm) option, and the Disc Trucker has a 640mm seat tube (64 cm) option.   Steel bikes often have horizontal (not sloped) top tubes, so you end up with much less seat post exposed. They also have round tubes so you can more easily find a longer seat post if need be. The extra weight isn't much assuming you spec it out with the right components for everything else. As most you'll end up with a couple extra pounds which won't be a huge percentage of your total weight (bike + rider).


Shimano 105 brifters (5800) and Avid BB5 compatibility Are Shimano 105 brifters (5800) compatible with Avid BB5 mechanical disc brakes?

Yes they are. I had Avid BB5 calipers with Ultegra 6800 levers (same cable pull as 105 5800) on a Specialized Tricross and they worked very well together.


I'm trying to find what model my Bianchi is I'm trying to know what model my Bianchi is. It's written "Mask Lite Alloy" on the body but couldn't find any other indicator for the model so does anyone has an idea what model it is?

It's sitting in my cousin's basement and he's planning to dump it or give it to someone else. That someone is me and I don't know how to figure out the model. The frame is aluminium by the way.

At first glance I thought it was horrid cheap late 90s BSO that someone had slapped a Bianchi sticker onto.

But no - here's a similar unit:

This was found at https://www.picclickimg.com/d/l400/pict/254206275588_/Bianchi-mountain-bike-for-competition.jpg but the site has somehow disconnected the image from the associated text.

I'd be hard-pressed to say which is the newer/older between this orange one and your one.  Both have old-style boots on the front suspension, which suggests late 90s.

The other find was a police auction website at https://www.propertyroom.com/l/bianchi-mountain-bike/12983885

Sadly this one has no useful details either.  This one has disk brakes, no stanchion boots, and is probably a much later model than the one above or yours.

Both the pictured bikes have both chainstays and something like seatstays, , whereas your one only shows beefy L-shaped stays holding the rear wheel.  This makes me suspect that your bike is the oldest, and the rear... fork (?) wasn't that good which is why later versions reverted to a separate triangle.

Personally I'd do basic maintenance, change the brake pads, clean it, and ride it.  The rear shock will be pretty useless after all this time (those shocks weren't very good to begin with.)   So just ride it.

There's almost nothing to be gained by knowing what model a bike is other than a general interest.  There will be no parts that are unique to this bike, other than the frame itself.  If you need a replacement part, take the old one to a LBS and ask for "one of these please"


Replace disc brake pads for Huffy mountain bike I have a Nighthawk Mens 18-Speed Mountain Bike. When it comes time to replace the disc brake pads, I saw that Huffy sells the whole brake caliper for $8.

It seems like it would be cheaper to just replace the pads, but I can not find them.

Chances are the calipers are compatible with with something like BB3 pads. Problem is finding some will be more expensive than buying new calipers. You could look at pictures and 'take a punt' buying off the internet, or go to local bike shop that can match to your calipers with new pads - but that will cost at least twice as much.

I suggest spending a bit more and upgrading to a known brand of caliper, so when it comes time to replace pads you don't need to go though the exercise again.


What size is the tiny ball bearing used in SRAM rim-brake caliper quick release detents? SRAM road rim-brake calipers (mine are specifically Rival from 2011) have a quick release lever to facilitate wheel changes, as many calipers do.  The SRAM QR lever has detents which make a little "click click click" noise and feeling as you rotate them.  Today I found out how that detent works, and wish I hadn't.

You see, I was replacing the M4x6 button-head screws on the QR "axle", as they were quite rusty (see SRAM Rival brake caliper screws/bolts are rusty, how to replace?).  I had unscrewed one of them a couple weeks ago to check the screw size, ordered the screws, and now had them in hand.  When I unscrewed the second one, I heard a little "ping" as something fell down on the floor.  I searched around for it, and behold, it was a tiny ball bearing!

So in the process of opening up the first brake a couple weeks ago, I'm sure the ball popped out of it, and the floor has been vacuumed since then so goodbye.

The question is: can someone tell me what size the ball bearing is?  I can tell you it's roughly 1-2mm, but I don't have sufficiently precise equipment to measure it.  Bonus points for a link to purchase replacements (in small quantities!).

As an aside, this design seems comically bad: they use a screw which for some reason is more prone to rust than any of the others in the groupset, and when you unscrew it there is this tiny metal ball sitting on a tiny metal spring waiting to eject it from the assembly.  It's no wonder why they don't call out these parts in the service manual!

The balls are 2mm in diameter.

How do I know?  Well, I found a bearing supply shop, and asked them to see some of their smallest balls.  I bought one 2mm ball and one 3/32" (2.38mm) ball for all of 20 cents.  The 3/32" ball was slightly too large to fit in the hole, so I tried the 2mm one, and bingo--a perfect fit.  Putting the QR mechanism back together is a pain because the tiny 2mm spring wants to eject the ball again, but with the brake facing straight down it's doable.


Are there special concerns traveling by plane carrying Air shocks? Are there any special concerns or precautions to take when traveling by plane with a bike that has air shock or air fork?

Is it necesary to take the air out or is it safe to leave them as they are?

By the way, the tires need to be deinflated?

Details: I'll be traveling by air with a bike that has a Marzocci Bomber MX Pro, that has air springs. My fear is that pressure changes may affect the shock. Also, and I don´t know if I will be near a bike shop at my destination.

Most (all?) airliner holds are pressurized and nearly all are heated, at least above freezing if not to cabin temperature, so I wouldn't expect any particular problems. The atmospheric pressure at sea level is around 14.7 psi, so even if the the hold was not pressurized at all, the worst your bike would see would be around 15psi extra pressure in the shocks/tires. The air pressure at 30,000 feet is around 4.4 psi, so at typical airliner cruising altitude, an unpressurized hold would mean that your tires and shocks would see about 10psi of additional apparent pressure.

If you were running some fat low-pressure tires on your bike pumped up to their maximum pressure, then you might want to back off on the pressure a bit for piece of mind just in case it ends up in an unpressurized hold, but I'd bet that even a bike tire rate at 30psi will stand up to 40psi without bursting. But I'd have no qualms at all about a 110psi bike tire standing up to 120psi in the plane.

Naturally, if the airline has any special requirements, you should follow those requirements, but I've flown my bike on several different airlines (including overseas), and have never seen a requirement to deflate the tires and have never had a problem.


What do I need to look for when buying a new rear wheel? This is my bike:

https://www.giant-bicycles.com/au/xtc-27dot5-2-2014

Stock rear wheel axle in the hub is broken. I couldn't find replacement axle so I need a new wheel.

I want to use my old disc brakes. Will certain wheels only accept certain disc brake sizes?
I want to use the old drive train / cassettes. Will certain drive trains / cassettes only fit on certain wheels?
I need a new quick release for my back wheel because the old one's grooves wore away. Will all quick release axles work for my bike? (ie. http://www.chainreactioncycles.com/au/en/hope-qr-steel-skewers-rear/rp-prod31896)
Can I fit a different sized wheel on the back than in the front? Would that cause any problems?

The wheel's hub has one of three possible rotor mounts - there's 6 bolts, two sizes of centerlock, and a very small chance of something else weird.

You need a hub that matches your rotor's mounts.  And yes there are adapters available, but you should buy what fits properly.  Do buy new bolts rather than reusing the old ones.

You have a 10 speed cassette, so you need a hub that takes a 10 speed cassette.  I believe 8-11 are all the same depth but the inter-cog spacing drops.
You probably will get a new skewer with your new wheel.  They're relatively cheap, you probably want a 135mm long one for the rear.  Your bike does not suit through-axles so you require QR-based wheels, or wheels that have adapters for QRs.  Wearing away like this might be a sign of something else being wrong.
Yes, but it gets messy very fast.  Refer to the large collection of existing Q&A on this:

Can I combine different wheel sizes in one mtb?
Is it worth swapping MTB front forks/wheel to ISO 584/27.5" from ISO559/26"?
Can I change my 28" wheels for 24"?
Disadvantages of run 650B wheelset on a 29'er
There are a lot of questions with very good answers on this site - do search them out.


How can I find out what's clicking on my bike? I've got a relatively new (~ 3 months old) road bike and whilst I'm riding I can hear a clicking noise coming from the bike. It seems to be when I apply pressure to the left crank. The bike is a Specialized Allez 2016, shown here.

Rotating the pedals on the cranks by hand, there doesn't appear to be any grinding from dust/grit ingress. Applying pressure to the pedals whilst the bike is stationary, there doesn't appear to any noises. There's no play in the crank arms when 'rocked' side to side. Rotating the cranks by hand whilst the bike is stationary, I can't hear the noise. I've removed by stem wiped and reinstalled along with the headset bolt, making sure not to over tighten the headset bolt. Bottle cages and frame pump bracket are secure on the bike, too.

I'm running out of ideas other than it being a bearing issue with the bottom bracket or the bearings in the pedals, but after such a short period of time, I find it hard to believe that they could have gone already - I've only done coming up to 600 miles on the bike.

I'm not sure how I can ascertain whether or not the noise if coming from the BB or pedals if I can't hear it when the pedals and/or cranks are rotated whilst stationary.

Anyone any ideas what I might have missed or more importantly how to troubleshoot further?

First of all, welcome to the "mysterious click" society!

The obvious first thing you want to check if this is pedal or not. Find a certain way to reproduce the click and reproduce it by pressing on the pedal, its furthest end, only. Then try to reproduce by pressing only crank by your foot using similar force (be careful, cranks are slippery!) and watch what happens. If click does not happen, then there's a good chance all you need is to tighten your pedal a bit.

If the click is still happening, check the screws on your stem and handlebar, saddle, also check if quick release levers are tight enough. These can click if too loose too. If you have a threaded stem, tighten the center screw - it does click if loose.

It is usually very hard to understand from where exactly the click comes. Try to apply the pressure without grabbing handlebars, try all kinds of tricks to understand what is clicking.

Carefully check out all the frame and cranks for cracks. Those can happen on new bikes too. Check your chain - may be there is a loose link?

If the click still happens, then it is a bit more mysterious than the usual causes. I have had a bike which was so mysterious so that even LBS disassembled it all and re-assembled for free - the click was gone that way. Reason still unknown.


Oiling bike frame to keep it cleaner? A friend recommended that I take an oily cloth (with regular motor oil or such) and wipe down the entire surface of my mountain bike frame. He claims that it's easier to hose off after, and it actually keeps cleaner. It seems counter-intuitive to me, as I think the dirt would just stick to the oil.

What do you think? Do you do this, and does it work for you?

I should add that this is for a wet, muddy climate; the argument being that oil repels water...

I'd think that oil would repel water (make washing harder) and attract dirt. Maybe since we're in such a wet climate (Andrew and I live near each other) it's decent advice to keep the rain/wet trails/dirt of your bike but I still think that your bike would gather dirt even in the West Coast rain. Especially in areas that are hard to get at like around the seat stays and seat tube.

We oil our chains and they get filthy, even on the road. I'm not sure why it would be any different with the frame.

I can't see any scenario where that is good advice. I agree with the comment that waxing would be a better option.


What should I be doing a week before a long distance bike ride? I have a 50 mile bike ride in 1 week.  I have been training for a while and I am trying to figure out, at this point, if I should be:

Training hard, doing a few long bike rides to get prepared
Resting and taking it easy.

I have heard both arguments (one saying to do a similar ride and others saying focus on resting)

Any suggestions for what to do a week before a big bike ride?

The correct answer is both. You should do a long ride, around 80% of your goal distance 4 days before your actual ride, and then rest off the bike for 3 days.

That gives your body a wake up call that serious exercise is coming, and then a rest period to build up for it.

This answer has some explanation about why, but the only real debate is in the timing of the ride and the length of the rest period.

For most people, 3 days is enough to recover, but not so much as to lose the gains you made.

FWIW, 50 miles is a long ride, but not so long as to need to be excessively concerned with your training schedule, as long as you've been putting miles on the bike, and as long as you pay attention to eating the right food, in enough quantity, both in preparation for the ride, and while doing it.


Race Face Crank/Chainring Compatibility I have a Race Face Evolve DH crankset which takes 104 BCD chainrings. However, I pulled a 104 BCD chainring off a Shimano Acera Crankset and the rings don't interface properly with the Race Face cranks. The chainring bolts line up, but the shape of the ring below the crank bolts has a different curvature and doesn't mate with the crank spider.

I'm trying to just buy cheap/durable steel chainrings for my mountain bike and didn't expect this incompatibility.

What chainrings are generally compatible with this crankset? Are sram/truvative rings generally compatible?

I had this problem with a pair of Race Face Cadence cranks (road version).  I think Race Face does this to force you into buying their chain rings.  I am sure there is some "engineering" argument why their rings are more compatible with their cranks, but frankly their rings are only so-so (my opinion).  So far every brand I have tried has this conflict as they use a square profile on the ring/crank interface, not a square with rounded corners.

To get around this simply Dremel or file off the offending material on the chain ring so it fits flush on the cranks.  Then pedal off (or glide downhill in you case) into the sunset with a smile on your face.  I have done this with a some FSA rings and have put 5000 km into them with no ill effects.

Take my anecdotal experience for what it is worth.


Does a carbon frame need two-bolt seat clamp? Does a bike with an alloy seat post and a carbon frame need a seat post clamp with two bolts? Most clamps these days seem to be either quick release or single bolt. Is that safe to use with my set up?

I have read a little around the subject and not found any definitive answer.

On carbon frames I've used, they have had a single bolt clamp like this one, so it should be fine. Personally, I'd like to use a slightly bigger clamp and one of those rubber size-decreasing rings to avoid cracking the frame. If in doubt I'd phone up the manufacturer of the frame and ask!


Why do some triathlon seatposts go straight up and down instead of at an angle? Why is it that some triathlon bikes have a seat post that adjusts straight up and down instead of the more standard axis that aims at the bottom bracket?

This means that if you raise (or lower) the seat on the special triathlon bikes, the torso/leg angle would change more than for a normal bike, right?  Doesn't this also mean that the straight-up vertical adjustment of these special triathlon bikes do not fit as wide a range of riders as if the seatpost adjusted in a way that kept the same torso/leg angle along the axis?

This question is not about triathlon bike geometry or efficiency of peddling.  Rather it asks about why the displayed vertical seatpost adjustment axis is used instead of a more standard adjustment axis for seatpost.

Here is a tri bike with the vertical seatpost:

Here is a more standard bike:

To crudely simplify things, a triathlon/TT bike position is much the same as a road position, but basically "rotated forward", so your arms rest atop the very-low-set bars. A consequence of this is, the seat ends up further forward.

(source)
Using Chris Froome's TT position as an example, noting the hip position versus the bottom-bracket position:

(source 1 and source 2 - I couldn't find a good side-on picture for the road-position, so it has quite a lot of skewing to align to the TT-position picture)
This "Proper Bike Fit for Triathletes" article has a vastly more detailed explanation (and is the source of the first diagram!)

Doesn't this also mean that the straight-up vertical adjustment of these special triathalon bikes do not fit as wide a range of riders as if the seatpost adjusted in a way that kept the same torso/leg angle along the axis?

As long as the frame is roughly the correct size, the tri bike should be just as adjustable as a road-bike, if not more..
Look at the tri bike image in your question - the saddle rails cover around 3/4 of the length of the saddle, allowing a greater range of movement forward/backwards (compared to the road bike, where the rail often covers less than half of the saddle)
Additionally, the aero-bars are much more adjustable than standard drop-bars (which are mostly limited to stem-length adjustments). Aero-bars can potentially be moved quite far forward or backwards (although at some point you will hinder steering/stability)


How should I install the front wheel of a Muddyfox Bike (UK) This is my first bike ordered online and I don't have much experience in assembling. My problem is with the front wheel, which according to the assembly guide just fit into the fork.

However there are two nuts attached to the bolt which, as far as I understand can't be taken out and, the fork does not have enough space to "contain" both nuts.

Please see the images, on the left side the nut is between the bike and the fork but on the right side the nut and the fork are aligned so that the wheel moves no longer into the fork.

Any help?

The nuts you see are bearing cone and locknut, and they should not be removed unless you are servicing the bearings.

This kind of tolerances are something to be expected from bikes at this budget. Your options are to spread the fork by force, or since the bike is mail order, just return the whole thing.


is it possible to put a bigger than 34t chainring on Merida e160? Is it possible to put a bigger than 34t chainring on a Merida e160 MTB? There is only about 2mm of clearance from the chainstay.

Depends what you mean by clearance. X or Y in the diagram below?

if you mean X then you likely have room for a bigger chainring. If you mean Y then you are probably out of luck.

Using a formula for the radius of an n sided polygon and assuming tooth profile does not significantly vary for different size chainrings, each additional tooth adds about 2mm of radius to the chainring.


2x10 drivetrain and chain crossing I've used to ride with 3x10 setup on my MTB. Now I've got a new one with 2x10 (Avalanche 9R Expert).

The question is: do I need to worry less or more about chain crossing on this bike?

This is not a duplicate since I'm mostly interested in difference between 3 and 2*10 setups in terms of chain crossing

The chain will travel less distance sideways, so less, but still if you are big front, big back, it may still touch the front derailleur. I wouldn't call it something to worry about though.