What is the purpose of the 'tire guide' screws on shimano brakes On Shimano Ultegra and Dura-ace brake calipers there are round-head slot screws in the lower section of the brake pad holder. In the BR-6600 spare parts catalogues they are labeled as 'tire guide' (item 13), however they are not mentioned in the user manual. They are also absent from Shimano 105 brakes and from comparable SRAM brakes. What is their function?

The 'tire guide' screws are for deep section carbon fibre rims.

The idea of the brake shoe holder is that you replace just the rubber bit, not the entire shoe. In this way you do not lose your settings, as happens when you replace the entire brake block, not just the rubber bit.

For speedy wheel swapping, i.e. in race conditions, the 'tire guide' exists. These have been round for a few decades and were originally conceived with square, box section rims in mind, e.g. original 'Mavic' rims such as the MA40.

The problem with deep section rims and tire guides is that, when the brake wears down, the rim can come in contact with the tire guide. The last thing the rim needs is to be scored all the way round by the metal tire guide. This could damage the rim beyond its cosmetic appearance. As for the brake block, the last thing it needs is for the tire guide part of it to be damaged by being worn off onto the rim. This would not be a problem if the whole brake block was swapped out when worn, but, nowadays, it is just the rubber bit that gets swapped out.

Enter the 'tire guide screws'. These are made of a plastic that wears away quicker than metal does. So, when the brakes are worn, the plastic shoe hits the deep section of the aero rim instead of the metal tire guide. The rider notices this through what the brakes feel and sound like, to hopefully cotton on that it is time to put some new brake block inserts in. Instead of the brake block holders and the rim getting damaged, these simple plastic screws get worn down. Replacement plastic screws don't come with the R55C carbon rim brake pad inserts, although they do come with the replacement brake blocks:

http://techdocs.shimano.com/media/techdocs/content/cycle/EV/service/EV-BR_SHOE-Road-1326N_v1_m56577569830698525.pdf

Personally I think it is interesting how patents like this work. There is 'prior art' with tire guides covered in a plastic coating from the pre-deep rim era, Shimano update the concept with nothing more than a plastic screw and get a patent out of it.


What kind of bicycles do they ride in the Tour de France? I've been looking at a lot of the coverage of the Tour de France. All of the attention is on the cyclists, and no attention whatsoever on the cycles. Even in photographs or videos, they are so far away, or the bikes are moving by so fast, you can't tell what they are riding.

I know I definitely can't afford whatever kind of bike they are using, and it would be horribly impractical for me to ride one since I'm commuting, not racing. I'm just very curious as to what is the top of the line in terms of bikes. When I look at high end bikes in shops or online I can't tell if they are actually superior or if they are just loaded with expensive gimmicks.

What frames, brakes, seats, gears, tires, etc. are the world's top competitors using?

The focus is on the riders, because the bikes are just not so different from one another. The UCI (international cyclists' union) tightly regulates what shape and weight the bike must be, and what technical solutions are acceptable, so the sponsoring manufacturers can only compete on relatively minor features such as aerodynamic tubing or frame stiffness. These are of no practical importance to an everyday cyclist.

A typical racing top-level bike nowadays will have

an aluminum or carbon fiber frame, with increasing focus on aerodynamics over weight (because it's relatively easy to achieve the UCI minimum weight of 6.7kg regardless)
always a carbon fiber fork
either super light or aerodynamic wheels, depending on the type of rider and needs of the particular stage
either Campagnolo Super Record, Shimano Dura Ace, or SRAM Red component set, depending on who's the sponsor


XC (mountain bike) tire for dry hardpack and loose conditions I am just looking for a a new set of tires for my front suspension mountain bike (has a newer nicer fork on it now).

I mostly ride in the Gatineau Park in Eastern Ontario.  The conditions are almost always dry.  There is quite a bit of loose gravel and a good amount of hardpack.  The terrine is pretty hilly and occasionally I find myself loosing traction on my rear tire while climbing.

Right now I am riding a pair of stock tires.  Both tires are pretty cheap.

Rear tire.
Front tire.

Am interesting in upgrading to get a bit more performance out of my bike.  Would also like to reduce the rolling resistance.

Couple questions:

What difference will more expensive tires make?
What width of tires will work best for the conditions described?
What price range is reasonable for a good set of XC tires?
Any other pieces of wisdom I should consider when choosing tires?
Any examples of good tires for these conditions.

A good quality bike tire usually has a better size tolerance, a better rubber compound (might make more difference on traction than thread geometry itself), a better seating on the rim, and a better "feel" - the tyre carcass reacts better to bumps and curves, have a good cushioning effect and a good rolling resistance. I'd say there is a perceiveably relationship between price and quality, or at least the vast majority of low-price tires are not very good compared to medium- to high-priced ones;
For the described conditions, I'd say 2.0 would be best, some might prefer 1.95, some up to 2.2. More than this is possible, but probably not necessary;
Cannot tell about price range, depends on country;
Tires are funny in a way that the best tires (so as the best suspensions) do their work quietly. If you notice that you just GO, enjoying the trail and never ever having to think about the tire, traction, cornering control, pinch flats, etc., then the tire is good, it's doing its magic. Not-so-good tyres constantly remind you they're there, and you end up thinking: "this f***ing tire sucks!";
Tire models/brands are a very personal matter, but I had good tires - ones that did their magic - from (not in any order) Bontrager, Specialized, Maxxis, Ritchey, WTB, Panaracer, Tioga.


Panniers on front suspension forks I currently have four panniers (two front, two rear) on my touring bike and plan to purchase a new touring bike which comes with front suspension forks. Is it possible and if so, safe to add front panniers to a front suspension fork?

Whether it's possible or not, it's a bad idea.

With any suspended system, there's sprung weight and unsprung weight. Sprung weight is the weight carried by the suspension system, and unsprung weight is the weight that's "downstream" of the suspension system (the wheels, etc). In any suspended system, the goal is to maximize the weight that is sprung, and minimize the weight that is unsprung.

When you go over a bump, your unsprung mass gets pushed up, then recoils and goes down, and this cycle repeats until the energy in the system has been damped out (vocabulary aside: although we casually refer to suspension as "shock absorbers", real shock absorbers only damp out the recoil, not the initial impact). Adding unsprung mass makes that recoil much harder to damp out. If you put, say, 2 kg of rack + bag on your front forks, and another 7 kg of load, you're exceeding what the front suspension was designed to handle by a factor of 4 or so. Not so much in terms of the initial shock (which I imagine can be many Gs) but in terms of absorbing recoil.


Easy build, high weight capacity trailer for Burning Man TL;DR
I want to make a high capacity trailer from bamboo to ride around at a desert festival.

Bamboo structure (probably 1.5" or 2" major strength lengths, 1" for crosses)
Hitch using bamboo & bamboo joints to get it up to a rack or seat post, with one of the varied DIY hitches seen around the internet.
simple wheels with high rated weight capacity, or dual wheels
simple steel length with clamps on each side of the wheel to mount,
similar clamps to mount to the bamboo
weight capacity will be 300+ pounds
Estimated costs (at the moment) $200-$250 just for the trailer structure & seat location, and budgeting for mistakes)

Long version:

I'm seriously considering a heavy duty bike trailer for this year at Burning Man (those who don't know, giant arts/community festival in the middle of the desert, so very flat). I'm planning on having a large capacity 36v battery pack as I'm going to get an electric front-wheel conversion kit, and I want plenty of power (plus for lighting & such). So if I go for 20 Ah pack, that's something like 40+ pounds. Then on the trailer a small-ish disco ball suspended off the back with lights for at night. And another 12v battery for all the lights. And a small lockable storage space for stuff. And then a seat for someone on it. So, all told, plan on 300 pound capacity.

Searching around the net (both here and elsewhere), I think I've settled on bamboo framing & structure for it's strength, lightweight, and easy to work with (no welding!).

The two things I'm uncertain of right now, are the hitch & wheels & wheel mounts.

Hitch, I can do something fairly simple to attach it to a rear rack or even seat post.

Wheels and wheel mount is more complicated. I've seen quite a few people have success with 20" BMX style wheels but I'm trying to keep costs somewhat down. Or maybe something like plastic 20" wheels or 24" MTB wheels from Northern tool. As an alternative, use a much lower rated wheel in 16 or 20 inch, but go dually, so 2 wheels on each side. For mounting, seems like I could even just get a length of steel from Home Depot in the right OD, cut it to length, and put some clamp thingies onto it to mount the wheel (which includes bearings) and drill a hole in the bamboo and do the same to hold it in place.

It's very flat terrain with semi-formed dirt roads, not going to be going very fast (maybe 10mph) does what I've said above seem doable?

It's not too hard to build a trailer that will handle 300lbs / 150kg, but moving the trailer and staying on the bike in front of it are very different problems.

First, moving the weight. The playa is not smooth, so you're going to need more force than you might expect just to make it move. But since you'll be going slowly you can simply gear down to deal with that. It will help if you have bigger wheels and fatter tyres, so the 24" wheels would IMO be a better option. Those are not as strong when dealing with side loads, but again you're not going fast so the big problem will be people jumping on the trailer rather than fast cornering. Try to load the trailer so it's not inviting to climb onto.

Second, staying on the bike. The simple part is balancing at low speed. If your bike is geared low enough that should be doable, I'd put the seat down so you can put feet on the ground easily and stand to pedal if you need to. The more difficult part is when one wheel hits a bump or pothole and the 150kg trailer decides to throw you sideways. The trailer might also be able to lift your rear wheel off the ground, at which point you're going to fall over. The other obvious route to the ground is someone stepping onto the back of trailer. You can reduce that problem by putting a bit of weight on the back of the bike - maybe put your battery pack there. That will also help with traction, especially if you're standing up to pedal.

If you can mount to one axle of the bike you'll be more stable. The higher up the attachment point on the bike the better leverage the trailer has to push you sideways. Ideally the hitch would be below the axle, and with a 26" wheel mountain bike doing the towing and 24" wheels on the trailer that will also help make the trailer level. Even dropping it an inch or two will help.

Hitch

If you can get access to a welder/someone to weld for you, that spring-and-chain hitch is very robust and unlikely to break or fail. It's pretty easy to make and if you prep it there's only 4 or 5 small welds to complete it.

But for a week of BM you can probably get away with just about anything. Even just cutting up a truck inner tube to make giant rubber bands and using them to tie a flexible lashing on the rear rack would probably work (test it well before you go, because if it doesn't work on site you're going to be grumpy).

Wheels

I think you underestimate the cheap wheels found on kids bikes. For a couple of weeks with 100kg on them, most 20" wheels will do fine. And kids bikes are often thrown away, so you can probably get them very cheaply. You will pay more for decent tyres (or a supply of puncture repair kits and tubes, if you decide to spend your time fixing punctures instead).

I think the main issue you're going to have is the dropout area. You need to distribute the axle load along the bamboo somehow, so it might be worth using MTB front forks on the wheels (running horizontally) as the attachment points for your lashing. If you use "recycled" kids bikes just cut the forks off at the fork crown, or even leave the steerer tube in place. That way you have a fairly long section to lash to (albeit all the load is at one end.

Design

I suggest a basic design like my megatrailer, scaled to fit your requirements. You could lash that up with bamboo, the main addition will be cross bracing of the bed so it doesn't turn into a non-rectangular parallelogram (wire or rope would also work). I've seen this rough design made of lashed bamboo before and it seemed to work.

A chariot design would also work - make the towing arm 2-4 metres long to reduce the forces at the bike end of it. That would simplify everything except getting it to the event. The more I think about that idea the more I like it. You can just use 2-3 lengths of thick bamboo as the towing arm, strap the front end to your bike rack and even just run one length down each side of the trailer. If you did that you'd want 4-6m lengths of bamboo, but it would look quite cool IMO.


Can't thread crank puller I'm in the process of replacing crankset and bottom bracket on my road bike - square taper type spindle. Bike is only four years old and bought from new, so all original parts with threads in good condition etc.
Trying to thread crank puller tool into cranks but can't seem to get it to screw in - obviously don't want to force it as it seems like hand tightening should be sufficient. Looks to be the correct size and cleaned & greased the threads of both the tool and the cranks.
Is there a particular technique to doing this or is it really just a case of turning clockwise and it starts to engage with the crank thread?
May be an age old question, but never done this before and don't want to risk damaging tools and/or components. Any suggestions appreciated.

Try removing the black finish with a small wire brush. It may be anondized and difficult to remove. Regrease both sets of threads. I always start by giving the tool a quarter turn or so to the left before proceeding to the right. Seems to line the threads up and helps prevent cross threading.
In this area of the bike (cranks, bottom bracket) it's best practice to at first hand thread the tool, bottom bracket cup, crank fixing bolt, etc as a measure to prevent cross threading.  Regarding the crank puller: the outer nut needs to be threaded fully into the crank arm good and tight before you attempt to wind in  the center bolt that pulls the crank arm. You risk damaging the crank arm threads if the tool isn't fully engaged with the crank arm. Thus "hand tight" as you described would be risky.  A common error related to this is not having that center bolt of the crank puller backed out enough and so it bottoms out on the square taper before the outer nut is fully engaged in the crank arm.  Same deal: the crank arm threads strip or become damaged making subsequent removal difficult or impossible without ruining the crank arm


Bicycle Geometry 101? Are there any resources or books that discuss bicycle geometry? I am looking for resources that would allow to get a rough idea of how relaxed or aggressive a particular bicycle geometry is, by looking at the manufacturer's geometry specs. I realize that it would only impart a very rough idea and that only a prolonged test ride and preferably long term use of the bike can impart a full impression.

I am mainly interested in traditional road  and touring bikes, but resources that address the same question in hybrids, and other bike styles are also welcome.

Tim Paterek Manual for Bicycle Framebuilders contains the chapter on geometry. Very old version of this manual can also be downloaded for free.


Are there very deep (>40mm) rims with at least 32 spoke holes? I've been looking some days for different wheel options and it looks like it is really hard to find rims that fulfill the following:

Deep rims (40mm or more)
At least 32-36 spokes
Durable (reliable for touring)
Reasonably priced (range 400-600€ both)
Don´t have to be ultralight but not much more than 1kg.

I really like riding with deep rims but I found only pre-built wheels in the following two categories:

Entry level: Wheels have the aero form just for aesthetics and usually are pretty bad, low number of spokes, crap hubs... Around 100-300€ per set.
Really expensive wheels of carbon fiber starting at around 1000€ per set.

Why is not there something in between? Is not there enough interest for such wheels? I think I have just seen 2 o 3 models which could fit and one of them is hard to get from Europe.

Very deep aero rims exist for one reason: To minimise drag. The difference, however, between, say, 20mm and 40mm deep rims, is not that big. So if you are concerned about drag, loosing a few spokes gives another few points in air resistance (as does using aero (blade) spokes).

To phrase it differently: You would not use the (much rarer) very deep rims unless you also save on drag by using less spokes.

I figure you are in fact not that concerned about drag. You did not speak highly of aesthetics either. That lets me assume you believe that deep rims are more durable. This has been discussed on this site here.

My recommendation would be a good, proven, durable rim with 36 spokes (they are in fact not that expensive) and, considering your budget, have your wheels build to your liking.

Edit (based on your comment):

You say you want your bike to be "fast during the week" for commuting. Bear in mind, though, that the clothing you would be most likely to wear or even panniers add considerable drag as well. The weight you will be carrying further limits the effectiveness. I can still recommend not being overly focussed on drag. If you fancy deep rims, go for them. But, unless you have a particularly long and exciting way to work, I am pretty sure you would be quite hard pressed to feel a difference between box rims with 36 spokes and very deep ones with 24 spokes, commuting.

Any usual number of spokes is fine to carry you (at 80kg). However, if you plan to carry loads (eg. doing groceries regularly), I would err on the safe side.


What Seatpost Is This? I saw a picture of a seatpost that I'd like to buy but cannot find after much browsing. Unfortunately I no longer have a photo but have this information about it. Can someone identify it?

Black. Not sure if it was carbon or not.
Had a stylized "C" on it.
Was described as a Campagnolo C-Record seatpost (although I have never seen any Campy seatpost like this before).
Traditional round (possibly 25mm) post which transitioned to an aero profile
Saddle rail attachment was the most distinguishing feature. It was composed of what appeared to be disks with a concave furrow around their perimeter (like a clothline pulley) on either side of the post. The bottom of the saddle rails rested on this. Then there was some other type of attachment (was hard to see detail) on the upper side of each saddle rail.

It was a thing of beauty.

Possibly you were thinking of Ciasta aero seatposts which has a similar logo?

Something like this perhaps...


Multi directional release pedals for road bicycling? I saw one Force model that looked like a separated part that might release, twisting your leg upwards or sideways or something. Reminded me of the toe realease on ski bindings.

Basically as many directions as possible that is adjustable all the way, with tension and float.

What I'm after in the end is getting my brain reflex to release once I know I will fall; I've falling hard on my hip a couple of times.

There is too much float on my current bike, so no way I can twist my foot out and release; as I would break my foot or something.

At least, that is what I think that my brain thinks.

You can put road pedals on a mountain bike and mountain bike pedals on a road bike. They're just pedals -- all that needs to match are the diameter+threads on the pedal. Of course, you may not look cool using pedal X on a road bike but you will look cool using it on a mountain bike and vice versa (but this is peripheral).

The main thing with any clipless system is to practice -- its pretty unnatural feeling to be clipped into a bike when you start. You will fall and thats part of learning. (Practicing cliping and unclipping on some grass while riding or just in a doorway or trainer clipping in and out repeatedly while stationary may help) But after riding for a while, it will be like second nature. Ski bindings release either by twisting (like bicycle clipless systems do, though for reasonable sized feet you can only twist one way -- twist your heel outward rather than inward) or by some forward force (which doesn't really make sense as a regular release mechanism due to the pedaling action on a bicycle).

That being said, there are a few adjustments you can make with a system:

Cleat position: You can move cleats back and forward a bit to make it more comfortable. You can also change the angle of the cleat to some extent depending on shoes and cleats.
Float: You can adjust the float (which allows your foot to move a bit, measured by angle) on pedals by either using different cleats or adjusting the cleat depending on the systems.
Tension: You can adjust the tension (how hard the pedals hold the cleat) normally by some small screw on some pedals. Setting it at its lightest setting will normally allow most people to take their foot out without much work even forcing it.

I'd start by setting the tension to as low as possible when learning and using a float setting to something not too high and not too low (the low end is normally fixed (0 deg) and high is normally 15 deg ish, but how well this feels depends on the pedal). For Look cleats, I'd suggest the grey or red (4.5 and 9 deg resp.) rather than the black (0 deg) to start with, but you'd have to try different float to see whats good for you.

There are many clipless systems on the market (Shimano SPD, SPD-SL, Crank Bros Eggbeaters, Look, Speedplay, etc.)-- some are harder than others. For example, many Shimano SPD pedals can be clipped from both sides and can have recessed cleat (so you can walk in the shoes easily), but SPD-SL can only be clipped from one side and portruding cleats (hard to walk). "Mountain biking" systems tend to be a bit easier than "road" systems (and many road bikers run the "mountain" SPD system). You may find one system works better for you than another, but you have to try them. Working with your local bike shop is best for this, because trying many at home is expensive. A bike fit may also help get you in the right position with clipless.

In the comments, Kibbee has pointed out two products which may be relevant: Shimano makes "multirelease" cleats for their SPD system, which are easier to release by rolling or twisting your foot in any direction. Shimano's Click'r system also is designed for getting in and out of easy.

Finally, clipless is not for everybody -- if you're perfectly happy with platform pedals or for some reason clipping in via toe clips, feel free to continue using it.


Swapping cranks, but the new crank is wider, how do I compensate for this? I was swapping the cranks and bottom bracket on my karate monkey from a Truvative stylo crankset (Mountain Double, GXP bottom bracket) to a Race Face Evolution DH (Mountain Triple, Race Face bottom bracket, It's Shimano Hollowtech II compatible I think).

However, the width (Q-factor?) of the Race Face triple crankset is wider than the Truvative Stylo.  If I install it and tighten the bolt, it looks to be 5mm+ of exposed space on the crank spindle and the crank arms can slide side to side through the bottom bracket since the spindle is so long.  I'm pretty sure my BB shell is 73mm (according to surly).

What do I need to do to compensate for this space?  Spacers between BB Shell and BB Cup? How many spacers will I need, and of what size? Is there some common spec listed for the cranks that I should have been able to tell this from the start?

You're right, you want to space it between the shell and cup.  You can put spacers on either side to get the chainline right.  Most cranksets come with spacers (2.5 mm is probably the most useful size for you) but if yours didn't any LBS should have a few to sell you.  Something like this: http://wheelsmfg.com/bottom-bracket-spacer.html (I don't know if these work with hollowtech BB's or not)

You'll probably want to get an assortment of sizes if you can, and use as few as possible to get things lined up (I assume this would help maximize BB stiffness, but really I just hate having excessive spacers - makes it more likely I'll lose one when disassembling/reassembling).


Upgrading gears from microshift to Shimano I have a Firestorm 29D (3 * 8 gears, 24 total) bike. The shifting is not smooth at all. I would like to upgrade my rear derailer and shifters or groupset to Shimano altus or any other. Kindly suggest me if its possible to do so.
Current configuration:

Shifters: Microshift TS38-8 3X8 Speed
Crankset: Prowheel 24X34X42T, 170mm
BB Set: Sealed Cartridge
Freewheel: Steel, 12-32T 8 Speed
Wheels: Alloy Double Wall 36H Rims
Rear Derailleur: Microshift RD-M25

I did try tuning it using the barrel adjuster but still the shifts are not smooth.
I was thinking of replacing the entire drive train. If Altus is not that good option what do you suggest is a good upgrade?
Yes I feel the same this gearset should have been smooth but it is not :( Since I bought this bike 2 months back I have rode a distance of 1000km.

Even cheap components should shift okay-ish, unless they are badly worn.
Shifting problems are usually caused by any combination of:

Bad adjustment: Incorrectly set cable tension or limit screws.
Excessive cable friction: Due to bad routing, worn cables, worn cables housing, missing/bad cable housing end caps or very low-quality cables.
Bent derailleur hanger. Look at the derailleur cage from behind the bike, it should be parallel to the center line of the bike.
User error: Don’t shift under (high) load. Don’t shift in a standstill.
Worn components. Usually the chain. You should replace the chain early enough, when it’s 0.75% stretched. This will typically be after 1000 to 4000km, depending on conditions. If you do so the cassette and chainrings can last more than 10000km. The derailleurs can also last more than 10000km.

Have you ruled out all of those? Only then would I think about a replacement/upgrade.


Do bar-ends with brake levers exist? I'd like to have those upward bar-ends, but with brake levers attached.

It's pretty hard to explain without a picture, but I hope someone understands what I'm looking for.

Does anything like this exist?

With any number of brake puller solutions such as this: http://www.amazon.com/Problem-Solvers-Cable-Doubler-Levers/dp/B001CK0R64 you can have as many levers as you want. Installing an additional lever and cabling isn't hard but if you don't want to do it your LBS will have no problem.


Upgrade the rear shock on my bike? I currently have a 2006 Cannondale Prophet 1000, that I use for trail riding. I would like to upgrade the Manitou Swinger rear shock I have. How do I know which shocks will work with my bike? Is there a guide to choosing a shock that will fit best?

Any shock with an eye to eye length of 20.0 cm (7.9 in) and 5.0cm (2.0in) stroke will fit as a direct replacement for your shock. All the shocks available as OEM options on the 2005 Prohphet used these dimensions.

Any different eye to eye length will alter the geometry of your bike. Any different stroke length will either reduce travel, or if risk damaging your frame if the travel is too long.

As to setup, that will depend on your weight and riding style. I will add that the prophet is a single pivot design, so you may benefit from platform technology to prevent bobbing.


help me identify/find more info about bmx forks with this symbol - & Trying to find out as much as I can about these forks and the logo. Originally the forks were grey and had a big sticker of this symbol ( & ) on one side. As you can see in the picture there is a small engraved & symbol on the bottom of the forks,but when I looked it upon google I couldn’t find anything. Any/all info anyone can help me find would be greatly appreciated !!

They are, unsurprisingly, called And Forks.

A close-up picture showing the logo, courtesy of VitalBMX:

The only other internet source I found on these is the following BMX Union interview, from 2011. So it seems that this brand never took off and those forks were quickly discontinued.


Pedals with largest outside platform area I am 86 years of age with RA and badly splayed out feet. I already have pedal extenders on my custom 350 watt ebike trike (on a Biria frame) and have wrapped rug/carpet laying  tape around the pedals with the rough gritty surface up - to no avail.

I have tried Amazon and eBay and can't identify a wide platform bike pedal that might solve my problem. Does any body out there have a solution or recommendation. Be an angel. Mike Crombie

Something like the Crank Bros Stamp pedals might work. The large version are recommended for people with size 10-15 feet, and they also have metal pins that stick out allowing your shoe to grip onto the pedal better.

It might make sense to go to a local bike shop to see what help they can give you. Seeing the pedals in person might let you know if they can work. Or they might be able connect you with someone in your area that modifies bicycles for people with mobility issues.


Bike shifts well for low gears OR high gears - but not both I have been having issues with my 9-speed rear derailleur and was hoping somebody could help shine some light on it. Thanks in advance! I can adjust my rear cable tension such that either the few top gears or few low gears will shift appropriately, but not both.

If I tighten the cable, the shifting for gears 1-2-3 is very smooth - but then trying to shift to 4-5-6-7 it gets a bit more sluggish and then 8-9 barely work at all (i.e. if the shifter is set to 8 it will stay in 7, and if the shifter is set to 9 it will stay in 8).

Conversely, if the cable is loose the bike shifts well in gears 1-2-3-4, but then it is very sluggish for 5-8, and when the bike is in 9 the chain is constantly trying to "jump" into 8th.

What I've done:
-The lower limit screw is set such that when the cable is disconnected the bike pedals in 1 smoothly
-The upper limit screw is set such that when I push the derailleur inward the bike pedals on 9 smoothly and I am unable to force the chain into the spokes
- I've replaced the derailleur hanger (as I read this is a common issue when a few gears present shifting issues)
- I've adjusted the B-tension screw such that the derailleur cog is 5 mm from the biggest cassette cog when in 1st gear

I'm wondering if the "range" over which the derailleur is moving left-right is slightly smaller than the cassette's width and therefore by tightening the cable I can force it to match the low gears fairly well, and vice versa for the high gears. I've googled pretty extensively and haven't found anybody else describing this issue unless they are trying to match shifters, derailleurs, and cassettes with different gear counts, which I am not.

If it's helpful: I recently converted by bike to a 1x9 using Shimano Alivio 9 speed shifter, Shimano Alivio Shadow 9 speed rear derailleur, Sunrace 11-40T 9 Speed Cassette and a JGbike derailleur hanger extender (the derailleur cog was running up against the biggest cassette cog)

When gears shift cleanly only over part of the cassette, it's often due to the alignment of the rear gears.  If you look directly at the position of the cassette gears and jockey wheels as you shift up-and-down, is the angle not-quite-right when the chain won't shift properly?

Even with a new hanger, if the gear mech itself or the extender has been bent, you might need to bend the hanger out of shape to compensate.  You can buy a hanger alignment tool if necessary (about £65, so not cheap).

Also... is it the smaller gears that aren't shifting?  Is there enough tension in the chain?  If you've bought a new chain, be aware that most are supplied with several extra links that you need to remove with a chain-splitting tool (which costs less than a tenner).

Otherwise, any kinks in the gear cable or grit/gunk in the cable housing could be affecting the cable tension.  It's worth replacing them periodically, and it's both cheap and easy to do.  You'd probably want to buy a good quality pair of cable cutters, though (£15+).

Hope this helps :-)


Which spoke type do I need for my bike? I have a Giant Trace X3 2012

It has 26" rims. Which of these spokes type do I need for my bike? Strongest or best match for the spokes I already have.

DT Swiss Champion Stainless PG Spokes
DT Swiss Champion Stainless DB Spokes

thank you

The difference is whether the spoke is butted or straight gauge.

A butted spoke is thinner in the middle, which allows more flexibility without damaging the wheel, which usually makes it the stronger, as well as the lighter choice. The choice is purely personal, though, and either will function as long as the lengths are correct. Note that not every spoke in a wheel set is the same length.


Inner elbow/bicep tendon pain from drop bars? I've just recently bought a new bike with drop bars for my daily commute. It's great fun and actual feels quite comfortable after following a few fitment videos and guides online.

The bike is a single speed Kona Paddy Wagon.

I have no pain or strain while riding, however at night the tendons on the of inside my elbow tighten up and get quite sore when used. It is really hard to pinpoint the pain, but it's not muscle, it's tendon. However the pain happens whenever I bend/flex my arm with the palm down or thumb up. When the palm is up, it doesn't hurt.

I'm not even 100% sure it's because of the bike, but the position my hand is in during the pain is basically the the hood position, so it makes sense.

Had anyone experienced this? It's what I imagine tendonitis might feel like.

During my attempt at setting things up, I managed to take a couple photos, I don't know if they help or not.

Tendonitis (tendonosis) is one possibility, however I would expect some pain during riding especially during the beginning of your ride. When you say biceps tendon I assume you mean near your elbow.

That said, the first things I would investigate are ulnar nerve irritation or compression at the cubital tunnel a/o the ligament of Struther's. The ulnar nerve weaves through several fibrotic "soft" tissues in the upper arm where entrapment can occur including the medial portion the triceps. The vibration of the road (absorbed by hand, triceps, and FCU muscle mentioned below) coupled with wrist extension and wrist radial deviation can put sustained tension on the ulnar nerve which can cause entrapment and damage.

The flexor carpi unlaris muscle can also contribute or cause this problem.  Repetitive inflammation of any tissue in the body results in the development of scar tissue which can occur between muscles, fascia, and within the sheath through which large nerves travel. As scar tissue continues to develop, the restrictions or fibrosis will increase in these areas.

Go see a LMT or chiropractor who is certified in Active Release Techniques so they can help break up the scar tissue and get that nerve moving more freely.  Surgery should be a last resort in this and most other repetitive use musculoskeletal injuries. This is related to and can be exacerbated by cyclist's palsy, and Tunnel of Guyon entrapment of the ulnar nerve. I experience this problem as well, mine is worsened by core weakness and too much pressure on the hands. Higher handlebars will help get some pressure off your FCU and triceps as well. They are ugly as sin, but those long tall quill stems are helpful.

Ride On.

Eric Poehlein DC


Mountain Bike on Paved Roads I'm an occasional biker. I bought a mountain bike (nothing fancy) with the idea that I might use it off-road or on mountain trails (of which there are many here in Calgary). However, since I've bought it I've done nothing but bike in the city on streets and paved bike trails.

Is there anything worth doing to my bike to convert it to something more suited to urban biking? In particular, the tires have me wondering; they have large rubber off-roading lugs that surely aren't doing me any favors on pavement. I'm not looking to spend a tons of money on a retrofit, but will do so if its worthwhile.

You can get a set of slicks or semi-slick tires that will reduce your rolling resistance. If you're using it to commute lots as well then fenders are awesome to keep the rain off. I have a snap on rear fender that goes on any bike I'm riding if it's raining (outside of races). I hate having a wet butt.


New Shimano 11 speed road chain problem I just bought a new 11 speed Shimano chain online. The wide end of the chain had a flat pin half sticking in, I tried to use a chain tool to release it a bit allowing for more room to connect the other end of the chain. Instead I accidentally removed it completely.

Now I can't get it back in like the other chain connectors. Do I need a Shimano chain Connector or is there another way to do it?

Can I just get some of the left over chain and add it to the other end getting rid of the part with the pin I knocked out or is it required?

Thanks

All Shimano chains I've fitted recently have come with a special connecting pin in the box, rather than a pre-fitted flat pin.

This dealers' manual for Shimano 11 speed chains only describes use of the bullet-shaped connecting pins: https://si.shimano.com/pdfs/dm/DM-CN0001-02-A-ENG.pdf

You can buy packs of 3 or more. Fit one then to avoid long walks, keep the others in your wallet or in your puncture repair kit.


Front hub not centered in dropouts Is there an adjustment which affects the amount of axle on each side of a front hub?

I have one wheel set, in which the front wheel does not center in the fork.  If I switch to another front wheel, that one does center properly in the fork. (Closing the quick release is difficult, one side of the fork gets pulled in). Therefore, I know the problem is not with the fork, but with this first wheel.  I suspect that something is wrong with the hub, and has been that way for the life of the wheel.

Is there an adjustment I can make to attempt to get the wheel to be properly centered in the fork?

I will answer my own question, I think I have figured it out.

The Shimano skewer is slightly thicker diameter than the skewer which originally came with the hub. (However, the skewer which came with the hub is poor quality and doesn't close very well.)  I think that the end cap is slightly too small diameter to let the Shimano skewer all the way through the axle and move freely.

I have a Bontrager skewer from another wheel set which seems to work.  Looking at the two skewers side by side, I can see where the Shimano gets larger diameter closer to the threads than the Bontrager skewer.

The hubs in question are branded "Pure" and the wheel set came from Bicycle Wheel Warehouse. Note that a Shimano skewer worked fine in the rear hub.

Not sure what I will do, as the Shimano skewers have the nicest cams.

If you see the comments, I was able to fix this problem by purchasing a new Shimano Ultegra skewer.  The threading was different on the Ultegra model, and it is compatible with these hubs.


Which electrical freight bicycle would you recommend? I am looking for a bicycle to make my car redundant for weekly groceries.
A typical Saturday trip would be to the department store(5 km) then to my parents for delivery (20 km) then to another shop (20 km) then back home (5 km), with a up to 45 kg of luggage.
The possibility to fix the dog in it or in the future to transport grand children would be an asset.
I was thinking of Larry vs Harry.com or Urban Arrow.

Any experience with these makes?
Any other suggestions?

Sadly these kinds of shopping questions tend to be closed as off-topic because they directly compare two things, and the answers only have a short shelf life.

My general advise is the same for any bike.  It must be comfortable for you, and fit you, and suit the environment in which you intent to use it.  That means getting a leg over and test-riding both.
Try and spend at least a short time on leg power only, before using the electrics.  You might feel differently about the options depending on that.
Extra thoughts about a cargo bike

They're not small - do you have room to store it?
They're not cheap - can you store it securely?  Cargo bikes are desirable and attract thieves.
Even unloaded cargo bikes tend to be heavy.  Will that be an issue (ie do you have stairs etc)
For the special loads, you'll want a bench seat, possibly removable. and a couple of seatbelts.   For the dog, you'll want an eyebolt or similar in the middle of the floor to secure a walking lead, to stop dog jumping over either side.
Insurance - does yours cover a pricy cargo bike?
Batteries - they tend to not last as long when the bike weight increases.  Make sure you can either fit several, or at least carry enough spares to swap.  On the flip side, its a bike, so ultimately you can pedal it without battery.  Thus "range anxiety" is less of an issue than an electric car where you're otherwise stranded.

Remember Batteries are consumables - make sure you can still buy them in the future.  They're not cheap either.


Shimano 105 compatible 13- or 14- cassettes I've just purchased a bike with a 105 group-set, 50 + 34 chainrings and a 11-34 cassette.

I was expecting to be able to replace the cassette with a closer ratio one, with a slightly lower top gear: maybe 13- or 14-. However the shop I purchased it from said the 105 rear mech wouldn't accommodate cassettes with a top ring smaller than 11 or 12.

Is this accurate? Surely if the derailleur can handle the combination of 50T chainring and a 13T or 14T sprocket two or three gears down from top, it can handle it 50T combined with 13T or 14T as top gear as well? Wouldn't a 14T-32T cassette require less forward and backward take-up from the derailleur, compared to the 11-34 cassette that's currently on the bike?

Modern rear derailleurs do in fact have a min and max smallest sprocket specification as well as largest min and max largest sprocket specification. You can find the specs here.

The min and max size of the sprockets is not just affected by the chain slack the derailleur can take up, it's affected by the angle of the line the cage moves along relative to the center plane of the bike to maintain separation from the cassette. This is different for short and long cage versions of derailleurs - a long cage derailleur moves at a different angle than a short cage to track a wider range cassette.

The current RD-7000 SS (short cage) and GS (long cage) min and max sprocket specs are:

                 SS    GS
Low        Max   30T   34T
sprocket   Min   25T   30T
Top        Max   14T   12T
sprocket   Min   11T   11T

So if you have a short cage version you can use a 14 tooth smallest sprocket.


How do I fit this pair of chain tensioners on my single speed bike? I have these chain tensioners:

How do I install them correctly on my single speed bike? Do they go on the inside or outside of the frame?

My dropouts look something like this:

Apologies if the answer is really obvious. Appreciate the help.

They look like you want those "in" the horizontal dropout. The bracket should cover the frame and as you tighten the bolt it will pull the axle further away from the cranks, tightening the chain along with it.

Be careful to not over tighten as you want a little 'slack' in the chain. Also, it is very easy to tighten one side more than the other resulting in your wheel not rolling straight (just slightly off center is what I see most often).


Tools required for trailbuilding? Shovel,
Saw,
Roulette (very long, perhaps even geodetic roulette),
Ax.

The trail will be built in a forest. So there's no rocks, just dirt, small stones and a lot of roots. What else will I need to build a good forest trail?

It depends a lot on the ambition of the trail and the local conditions. Are you trimming branches in a forest or creating a safe path down a rock face?

Other dirt-working tools will probably be helpful, a pick and wheelbarrow are the obvious ones I can think of. Knowlege of how to safely prune trees and plants, plus some knowlege of trail construction, and some skill at dealing with people might be handy (I'm not sure whether skills count as tools in the same way knowlege does).

Consumables like tree repair paint and gravel will be useful and possibly necessary.

If you have significant embankments you can definitely move concrete embankment bracing segments by hand, but a motor vehicle would make that easier. If you're using concrete a trowel would be good. If you're driving stakes a sledgehammer is essential (and if you're not, what holds your anti-erosion material in place?)

The limited MTB trail making I have done has all just required a spade, hammer and supply of pegs (I have used a small axe for the latter two but it's not a good idea). Stuff that I could carry on my bike, in other words.


Spongy brakes/ deeper brake press My hydraulic brake (both left and right) has gotten weaker. I don't know how to say it, but it's like my brakes can now be pressed deeper. My front brake is so bad that it is touching the grips. I got this problem after a crash I had. Can someone help me find a solution to fix this?

If both brakes are exhibiting the same issue, and the issue had developed in parallel over time it's likely that they just need to be bled.

If a crash caused damage and allowed air to enter the braking system, it's likely that only one brake would be affected.

You should inspect the entire brake system looking for damage. Also check the brake pad wear and sticking pistons.


How cities came to decision to allow bicycles and/or motorcycles to enter bus lanes? Some cities debate about letting 2-wheel wehicles (bicycles or motorcycles) enter bus lanes. Why should (or not) we let them enter? When it is ok to let them use bus lanes? What factors should be taken into account? What kind of evaluation should be made?

This is not a definitive answer, but it's too long for a comment.

The primary purpose of bus lanes is to allow buses to move (more) quickly through peak hour traffic congestion. A bus carrying 50 people is using about the same road space as 3 cars when moving.

It's also a political statement to car users: take the bus to get there quicker.

If we allow other vehicles to use the bus lane then

The other vehicles must not slow the buses down.
The other vehicles must also make more efficient use of road space than cars.
And the message should be consistent.

In a traffic mix where motorcycles are less than about 3% of the traffic they will probably not impede the buses, by my guestimates. Another solution is to allow the motorcycles to filter through stationary traffic.

In a location where the buses average 20 kph then cyclists are not likely to delay buses unless there are many more cyclists than buses. This case would be rare, but possibly occurs in a few places in Western Europe. In these locations there would be no benefit in mixing cyclists and buses.

More common is the case where the buses average 40 kph and cyclists are rare enough that the buses can pass in reasonable safety. In this situation mixing cyclists and buses makes sense in policy terms, because the three principles mentioned above are supported. In practice the bus drivers need training to mix safely and consistently with bicycle traffic.

So it's about the relative frequencies of the vehicles in the traffic mix, and their relative speeds.


Is there any use to motor pacing for people in the cat 4 to cat 2 range actually useful? In the local cycling club some people are keen on racing but are no higher than cat 3 in the events that they can enter and the power that they produce. The general consensus is that motor pacing could be the 'secret sauce' that improves everyone's level of performance before next years race season.

Other are sceptical and make the point that its only for people with high enough power outputs that can only be consistently matched by a motorcycle. I agree with this point but cant help but wonder if there is something I am missing, does pedalling at this speed and cadence prepare your legs faster or could the same effects (for cat 4-3 power riders) be achieved by fast group rides?

Background

If you have the resources (motor scooter and someone experience in how to do it) and time, motor pacing could be very good training tool for building high-end power for a variety of fitness levels. Where it excels (when done properly) is getting riders to train at their lactic threshold. Motor pacing will push you to levels that are hard to replicate outside of real race conditions.

The consistency of motor pacing is also great as you can fine tune the intensity. The fine tuning allows you to sit closer and longer on your threshold than might be possible with a group of riders, especially if your group of riders has limited riding experience and differing fitnesses. Motor pacing can also accommodate a variety of fitness levels, the driver simply drives at the appropriate pace to put the rider at their threshold.

Now will this be the "secret sauce?" I have some doubts for the following reasons:

1) Drawbacks for inexperienced riders / clubs

Cat 3 can represent a wide array of abilities and skills depending on your region. Many newer riders do not know what it is like to ride at their true threshold.  They hold back, resist the wonderful lactic acid pain rather than embrace it.  For them, motor pacing may have fewer benefits over regular fast club rides.

Inexperienced riders also may not have the riding skill to motor pace safely. To motor pace well you have to be able to ride with your front wheel an few inches from the tire of the lead vehicle. This can be dangerous for unexperienced riders who may suffer from lapses in concentration.

Your diver must also be experienced.  I have paced behind an inexperienced driver and it was frightening to say the least.  Their speed would surge and slow and at one point I actually hit the vehicle with my front wheel.  I didn't crash, but this could have bee some serious carnage, especially for the riders down stream of me.

2) Raw Power Rarely Wins Races

Very few riders win races by riding off the front with their superior power. If you see someone riding off the front of a pack it is because the pack has allowed it, it is not due to their 'superior' power.  Very few riders ever ride away from the group through pure strength. Ones that do are typically so naturally strong their rarely stay long in Cat 3 anyway and in few years will likely be riding pro.

Not everyone has this genetic ability, and its also not the only way to win races at the local level. Strategy and race smarts can be of equally importance. I find many new racers overvalue fitness and undervalue learning how to read races and plan efforts. Too many are too twitching looking to jump on and 'go fast' too early in the race. For these riders motor pacing will not teach them how to read races.  It will not teach them how to make a plan, and commit every last ounce of energy to it's execution (i.e., execute, or fall in the ditch in exhaustion).  It will not teach them how to neutrally deconstruct a race and assess what worked and what didn't and come up with revised strategies to try the next race. It will not magically impart singular focus and the passion needed to win.

That said, motor pacing can still be a frickin' blast when done right!


Determine what headset bearing size The headset bearings are going out in my bike.  How do I determine what I need to order.  See pictures that might be helpful.

The Bike is an older Trek 3700.

Thanks,
Paul

That size looks like an EC34 (external cups, 34mm inner head tube diameter for forks with 1.125 inch steerer tubes).

You'll either have loose balls, balls with a retaining cage (metal or plastic), or cartridge bearings.

If you have caged bearings, loose bearings will work fine but be more fiddly to install. Take one to your LBS or hardware store.

If you have cartridge bearings, the size will be moulded into one of the rubber seals or be laser-etched on the side of the casing. Your LBS may stock one or two common sizes if you're lucky. Otherwise either buy a complete headset which uses the same size, or buy a complete headset and get it fitted or press it in yourself. Complete headsets can be cheaper than replacement bearings but the cost of paying a mechanic to install it will exceed the part cost.

TH Industries make the bearings used in many headsets. Their brand FSA offers a variety of affordable good quality headsets.


Comfort Bike for commuting? I currently have a Trek 3500 Mountain bike which I use for commuting 34km total each day. I did put on thinner tires. My average speed is about 20 - 22 km/hr
I'm tired of the leaning forward all the time and was considering getting a "comfort bike" where the handlebars are higher than the seat.  This would provide a much more enjoyable view/ride. I'm thinking something like this:
http://www.primeauvelo.com/en/cypress-dx-42604-0014040.html

IMHO I am guessing (please correct if I'm wrong) that once you go non-road bike, the differences of hybrids are marginal.  I believe most (all?) hybrids have more or less the same top speed, and my question is - would a comfort bike be more or less the same as a hybrid, but a hell of a lot more comfy.

I commute on 28 km/day at 22-25 km/h average. I normally use a city bike, where I am not exactly leaning forward but neither sitting at 90 degrees.

However, I had to use for an entire week a different model, where I was more "seated":

though at the beginning I was feeling more relaxed, on the long run it was not that comfortable: keeping a decent pace was a struggle (drag and head wind, feet slipping on pedals), and also the steering was far less precise than I wanted, resulting in slower rides.

Maybe see if you can borrow such a (or similar) bike and use it for a week or so, before switching to it.


Any thoughts on spoke lights? I was considering getting some spoke lights to increase visibility at night, and although there are a number of options they all seems to have a relatively low battery life, or get bad reviews. Here are some examples:

http://www.niteize.com/products/spokelit
http://www.monkeylectric.com/
http://www.cateye.com/en/products/detail/SL-LD120/

The best value for money would probably be getting some reflector tape, however it doesn't offer as much visibility and also relies on the light shining directly on you.

So if you were to recommend a spoke light, what would it be?

P.S. What surprised me is that I haven't seen any battery-less solutions, which I would have thought would be the obvious choice.

EDIT: Are revolights a good idea? Some things to consider before getting Revolights (which I will, because they are so damn cool)

From my trials with spoke lights I have not found ones that I like, but I have learned a few things about them that might be useful to others with more money.

Illumination - It is important to recognize how much light the lights can put out, and not just when the batteries are fully charged.
Batteries - There are a multitude of spoke lights with all sorts of battery requirements. A lot of them use the disk shaped batteries. These range in hassle to install and maintain since some of them only use a single battery while others use varying amounts in different quantities.
Ease of activation and deactivation - Some are easier to turn on and off then others. I prefer buttons rather then those you have to press on both sides. When you are riding around in the winter, one of the times you need to be seen the most, and you have frozen fingers turning lights on and off can be quite painful. Having lights that won't hurt your fingers might be a godsend.
Cost/benefit ratio - The aforementioned Monkey Lights may provide a lot of illumination, not to mention a few points in style, but they are not cheap. God forbid your bike gets stolen. Besides I can think of a few other areas on my bike I would want to drop that money on. But hey, at least you will get noticed.

Personally, I don't like the design of the SpokeLit. It fails on 3 of 4 of my qualifications. They are a pain to turn on and off. They do not stay bright for long and the batteries are expensive. Granted I ride a lot so your battery life may differ. What I have thought about doing is wrapping my spokes in Glowire or something like it.


How to "shop" for bikes via mail order What is a good method for finding a bike which matches my riding style, body measurements and bank account size when not able to actually go and try the given candidate bike model(s) in-person?

In my particular case, I live in a corner of the world where the type of bikes carried by almost all dealers (large and small) are in no way what I want: I want something akin to a classic "randonneuring" bike, but there is only one shop which "carries" anything close to that-- the shop has a single Kona Honky Tonk, and their solution would be to e.g. add fenders, racks, etc. Perhaps this is in fact a good solution, but I would like to have more than one available to me.

Manufacturers/models

Obviously, I can do research on the Internet to find appropriate manufacturers/models (e.g. Kona, Surly, Salsa), but I would need to actually get one of these bikes, and they don't always deliver (I am outside the US, and it's even harder to find local brands which make similar bikes because everyone wants a bike suitable either for Grandma or for Lance Armstrong despite still riding in their Lycra more slowly than I can walk in ski boots).

Fit/sizing

However, even after finding a potential choice for me, how can I even know if it fits me?-- I'm not a freak or anything (180cm and ~67kg), but I do know how differently even different road bikes "feel", and so the idea of ordering a bike online sounds like a bad idea to begin with.

Maintenance/repair

Although many bike components are more or less standardized to some extent, might I still not need to get some components which are "exotic" to my location, given that the bikes themselves are not sold here?-- having to mail-order a replacement for something which broke unexpectedly would be a tad annoying.

So, is there a reasonable non-local solution here for me, or might the best solution to simply be to do as the Romans do?

Thanks for the advice.

I would suggest a serious conversation with your local bike shop(s).

Do your research, identify what you want, and ask them to do a bike fitting and order the correct size for you.

The idea is to encourage them to invest in you while you invest in them. They may want a deposit up front. But if you can convince them to get what you want, you have started a relationship, and can expect benefits such as service when you need it.

If you just buy from mail order or the internet, then when you have a problem that you cannot solve, you'll be stuck. Shops can be a little less helpful when they know the online origin of the bike.

If the first shop wont do it try the next, and play one against the other. If there's only one shop then work on your relationship with them before you "pop the question".

BTW your weight and height are similar to mine - not unusual - but arms / legs / body sizes differ so do get a proper fitting.


What's the approximate stack and reach for a 5'10" 178cm man The top-tube length is no longer a good measurement for sizing a bike. Stack and reach are better for reasons I won't reiterate here.
The problem is, while there are many lookup tables and calculators to roughly guess a top-tube length for person's height, I cannot find the same for S&R.
The long and detailed articles on S&R (etc.) only talk about how to measure it on your bike, and not how it maps to the reader's body in a practical way where they can immediately apply it to shopping online.
Whenever someone asks my question, the responses (across the web) avoid a direct answer and offer instead that "its complicated", "get a proper bike fit", "go into a shop" or "you can only know by riding".
But these answers don't help at all. The reader is left with no answer and they just fall back to using the original flawed top-tube vs. height when choosing a bike from an online seller, hence every advert still quotes the TT length.
So, I know its complicated, but if the bike mags are right, then I'm better off shopping to a flawed S&R measurement than to an even worse top-tube length.
I assume that OEMs choose perhaps 5 different S&R sizes for their frames to target a set of approximate customer heights, so there must be a table somewhere.
What's the ballpark S&R for a 178cm man? (thanks!) ...inside leg, 85cm

The lack of definitive answers you've noticed is due to the amount of (often unknown) variables at play here. Body height and inseam are indeed good starting points, but people around the internet won't be able to estimate just how flexible you happen to be. Arm length, discipline and your personal preference on how 'aggressive' of a riding position you want also play a major role.
In this light, the advice you've received is reasonably good. After riding a certain bicycle long enough to get a feel of it, you'll be able compare the S&R of that bike to another one and make a somewhat educated guess on how that other bike would feel for you. The perk of going to a bike shop is the opportunity to throw your leg over bikes of your choosing, which likewise will give you some sort of an idea of which size would fit you.
Of course, your question is valid in a sense that for most people, there exists a ballpark of S&R measurements where they should probably start looking at. However, bike manufacturers often got your back on this. Along with the geometry charts, most of them provide you with a model-specific rider height recommendation. While it's not technically a S&R recommendation for your specific dimensions, it's the starting point you should be looking at instead of any arbitrary stack and reach that you haven't tried yourself.


Visible play in the front wheel that is not in the thru axle but in the hub itself? (video included) The video shows that the play seems to be in the hub:

Is it the bearings causing this? Are they worn out or not adjusted?
What steps can I take to resolve this play?

Yes, this is play in the bearings. How to fix it depends on the type of hub you have.
'Cup and cone' bearing hubs have ball bearings between fixed cups in the hub and adjustable cones on a threaded axle. These can be adjusted to take out play.
Other hubs have pressed-in cartridge bearings. These just need to get replaced , you'll probably need a bike repair shop to do this for you as they will have the required tools.
You may be able to do some research and find what type of bearings you have, otherwise you'll need to start disassembling.


What is the torque needed for chainring bolts? I have a bike that is no longer in production, but it has a standard drivetrain (FSA). I had some shifting issues the past couple days, and to my surprise when I did a clean/inspect, three of the 5 chainring bolts had dropped out and the other two were finger loose.

I salvaged some bolts from my donor bike. I needed a breaker attachment to my 5mm hex to get them off. There was no residual threadlock on the threads. Now I'm unsure how hard I should tighten them onto the first bike.

Why would they have come loose in the first place? How hard should I tighten them to prevent this from happening again? Would a dab of threadlock be good insurance?

A Shimano "General Operations" manual states the tightening torque for road chainwheels is 12-14 N-m.  For mountain bike chainwheels it's upped to 14-16 N-m for large and middle ring and 16-17 N-m for the smallest ring of a triple.
The website: http://si.shimano.com/#/
The manual number I'm referring to: DM-GN0001-20-ENG.pdf
Blue loctite or equivalent threadlocker is indicated here as well.
I can't accurately surmise the cause of the loose and lost bolts in this specific case. However my experience with situations of loosening bolts or part failure due to "coming apart"  in various mechanical settings often comes down to incorrect or incomplete tightening of the fastener (bolt, nut, etc). Part of this process is rechecking and re-torqueing after a break-in period of normal use.


Rear derailleur does not downshift properly, shifts up smoothly I can't get my rear derailleur to downshift properly. Especially in the middle of the cassette it'll delay a bit before shifting.

Limits are set correctly.

Since I can't explain this properly I recorded a video

My only guess is it being slightly bent.

This looks like a classic case of the cable sticking in the housing momentarily as the shifter lets out cable to downshift.

Your indexing looks fine as the chain is not rattling or trying to shift on it's own. FYI the derailleur high and low limits do not affect shifting or indexing.

Try removing the cable, wiping it down with a clean rag, applying a little chain lube and reinstalling. If that does not work replace the cable and housing. One cable and a length of housing is not expensive.


Shifter doesn't reach bigger gears My gear shifters (c. 2000 Shimano XT) will not shift to the bigger cogs (higher cable tension). Pushing the shift lever doesn't move the indicator past about half way so I can't reach the big cog on the front, or the lower gears at the back, it just doesn't click up into the next gear.

The bike is about 16 years old, so I'm guessing something in the shifters has worn out, but I thought I'd ask here in case there's something I missed and they're repairable!

I went to my local bike shop and they advised me to open up the shifters and give them a good spray inside with wd40, since it could be caused by the internals getting clogged up with dirt and grease.

This worked great and I can reach all the gears now, just need a little adjustment and then I'm good to go!

The bike shop was Ralph Colemans Cycles in Taunton, very helpful staff!


Disc brakes make noise My disc-brakes on my mountain bike sing/scream when I brake. I have tried to clean them, but it didn't work. Should I replace the disks or the brake pads? Is there a better (cheaper) way to fix this.

In short, squeaking brakes are caused by the sound of your pads sticking then slipping increadibly quickly, rather than applying presssure to your discs smoothly.

Solution:  Sometimes these problems can be a right pain in the butt.  Sometimes your brakes need time to bed in, sometimes, as you know, your discs just need cleaning, or importantly, drying. But if that doesn't work you need to rough up your discs.  You can get products with abrasives in them just for this purpose, or, less expensively.. I know many people have had success with very fine sand paper.

Give that a try before replacing your discs.


What type of lubricant/grease is most suitable for brake and shift cables? I bought this lube some time back when I cleaned the bearings in my rear wheel:

Now I am replacing all the cables on my bike and the instructions say to use white lithium grease. While I was at the bike shop yesterday, I asked the guy if the above ParkTool grease would suffice and he said it would. However, someone online said that this grease would not work as it would introduce friction within the cable housing.

So what is the correct answer? If I already put that lube on my cables, should I clean it off (if that's even possible) and apply the proper grease?

Edit: For anyone wondering, here's the cable kit I bought:

https://www.amazon.com/gp/product/B00L8NDVD6

And here are the instructions:

A heavy grease may introduce drag between the cable and housing, so a light lithium grease is preferable.

Lubricants can trap dirt and grit, meaning a greased cable would work better than a dry cable initially, but soon become contaminated such that the greased cable is worse.

Using a teflon-coated cable will avoid the need for lubrication and prevent water from being in contact with the steel strands.


How long can I ride my bike with a worn cassette? I took my bike to the mechanics the other day and along with needing my chain replaced they said that I also need my cassette changed and the front cogs.

I was wondering how long I can ride my bike now with a worn cassette before it becomes unridable? The teeth on the cogs seem a bit worn but they are nowhere near as bad as what I have seen on other videos.

What can I expect to happen when the cassette does start to fail? Gear slipping? Crunching sounds?

In my experience, skipping in certain gears at the rear is the first sign.
Usually in the most used sprocket.

Then the chain becomes worn - and perhaps starts to snap - and when you order a replacement - it skips all over the place because it is being run on an overly worn drive-train. You might be able to salvage the old chain and run it for a bit longer - but sooner or later - you have to bite-the-bullet and buy complete new drive-train.

But if your current drive-train is happy and not exhibiting any malfunction (keep that chain clean and oiled) - you could go for many many many miles on it.


Need help identifying a bike We bought this bike from a boy scout camp in Baltimore MD called Broadcreek about 3 years ago. They were donated to the camp to be used by camp counselors.  We have contacted the camp but o one has any idea to their brand.  It was red but we painted it for my daughter.  We know the following, it has a rear disk brake, it is a 3 speed that shifts on the handle.  We were told it has "internal gears".  It is relatively new because it has a built in light on the front and back and they are LEDs'  The lights don't have a switch and we put in new batteries and the front flashed and then did not work.  She gets all kinds of questions about it ("is that electric?", "where did you get that thing?") and she would love to have an answer and get the lights working.  thank you in advance for your help.

A friend told me it may be from a bike share.

We found it!  Somehow it came to Marlyand by way of Barcelona! http://www.barcelonayellow.com/bcn-transport/78-bicing-city-bikes


2014 vs 6061 vs 7075 aluminium components I saw a crankset made of 2014-T6 aluminum alloy (so it was claimed).

I read that this alloy is somewhere in between 6061 and 7075 in terms of strength. I also learned that it is also more brittle than both 7075 and 6061. But the thing that caught my attention was its bad corrosion resistance. According to the Wikipedia:

  The corrosion resistance of this alloy is particularly poor.

Hence I'm curious if it is worth to get a chainring made of 2014-T6? I am more interested in its durability as I am not into any competitive riding.

Other than from corrosion, do I need to worry about other types of failures?

Aluminum alloy 2014 is often used in the aircraft industry for structural support beams and the auto industry for truck frames.
See metallurgy reference.  It outta be just fine for a chainring.

Alloy 2014 T6 has a Tensile strength (ability to resist stretching forces) of about 483 MPa which is comparable to structural steel and much higher than 6061 T6 aluminum's 300 MPa.  This strength is achieved with a tremendous weight savings (as opposed to steel).    All this is to say that it appears the 2014 aluminum is stiffer than some other possible materials which is beneficial in a crankset so that more pedalling power goes to crank rotation and not lost through material flex.

Regarding cracking, that increased susceptibility of 2014 is confined to manufacturing processes such as welding, where special support of the piece is required, or where bending the alloy is needed, avoiding sharp turns is necessary.    Oxidation prevention in pieces made of 2014 alloy is carried out by bonding a thin layer of pure aluminum (a "skin") or some form of painting, anodizing or powder coating to the outside.


Debugging an FD problem through three visuals The front derailleur cable is as taut

as I can get it.

To attach the cable with as much tension, it's first necessary to understand the inside of the barrel adjuster.

And the H limit screw on a Sora FD is so undone (top red arrow)

it does not even touch its footing (bottom red arrow).  (The yellow ball is removed.)

Yet when the chain is on the larger chainring and on any of the three smallest cogs, the chain rubs (red arrow)

against the FD cage on the outside.

What else should I try?

If at this point I insert a tougher rubber ball to tighten the FD cable even further, the cage does get off the chain. Is that an indication that my best effort to pull the cable hard before tightening it was not good enough, and I should try pulling harder?

Components: Sora Sora R3000 front derailleur and ST-R3000-L shifter.

Update (question re "judgment" tool, following Nathan Knutson's answer):

The cable goes from one geometric point (bottom red arrow) on the bottom bracket to another geometric point (top red arrow) on the derailleur. There is no tweaking possible to the location of these two geometric points. What is, then, the purpose of the judgment tool?

I'm going to assume you've got FD-R3000 and are pairing with a compatible road double shifter.

The anchor position is adjustible. Follow the procedure in the Shimano dealer manual for your model. It is available at si.shimano.com. There are only two positions so if you don't have the special angle-finding tool you can use process of elimination. Failure to use the right position can cause what you're experiencing. The two different positions slightly alter the lateral point on the arm where the cable is anchored, which tunes the total throw.

All the "long-armed" Shimano road front derailleurs have the quirk of needing a ton of cable tension. The axiom with them is that once the right anchor position is chosen and assuming compatible parts, setup problems are almost always due to inadequate tension. They don't conform to generic instructions for FD setup. A good procedure is start with the shifter and barrel adjuster in the slackest position, then use pliers, a fourth hand tool, or the inner limit to pre-actuate the heck out of the FD as you pull the cable tight while anchoring the cable, then add some more tension as needed with the barrel adjuster after that.

You usually must accept essentially zero clearance between the chain and inner cage in the low gear with these derailleurs.

Another compounding factor to difficulty adjusting the "long arm" FDs is that the cable is anchored in a rather bent position with them, which can make it difficult to simply loosen the anchor bolt and pull out more slack - the memory of the material makes it want to return to how it was. You can try making a marking on the cable where it was exiting the anchor previously in order to be more sure you've actually added tension.


Why is my Hope XC freehub locking when the quick release is tightened? Recently I found that the freehub on my Hope XC rear hub won't rotate, but only when the wheel is in the bike and the quick release is tightened.

I've removed the freehub (which slides off easily), and serviced the pawls and springs.

I thought perhaps tightening the QR pushes the freehub against the lip seal, preventing it from rotating.

I spoke to Hope, who suggested that it might be that the internal spacer has worn. However, when I insert a small washer behind the spacer and install the wheel again the freehub still locks, despite there now being a visible (though small) gap between the freehub body and the lip seal.

Here's a link to the exploded diagram:

http://www.hopetech.com/webtop/modules/_repository/documents/XCRearHubExploded.pdf

The spacer I'm referring to is item number 5. The seal is item 11 - the 11 nearest the right (there are two).

The behaviour is the same with the cassette removed.

The cartridge bearings in the freehub body were worn. Actually, only the one nearest the hub body was jammed. I've obtained replacements and all is well again. It was a relatively simple (though noisy) job to bash them out with an old screwdriver (remember to remove circlips first - a circlip tool came in handy).


Small non-folding bike Are there any small non-folding bikes, of relatively good quality?

From what I see around, Brompton/Dahon produce only folding ones.

Ideally, should be under 10 kg, and have a few gears (but single gear is fine as well). I don't care so much about the structure (frame type/wheel size), as long as I can use it comfortably for short city distances.

I don't entirely exclude folding ones - but the folding mechanism clearly has a cost, and it's something I don't really need. The target is more a bike with small frame/wheels, and longer saddle/handlebar supports.

The Big Shot Mini Polo would be a good option, but the seller said they don't produce it anymore.
The A-Bike could be an option.

I'm a ~70/75kg 5'10" person.

====================

Post purchase edit:

I ended up buying an A-Bike, and while on paper it could be an acceptable bike, its engineering is a disaster.

Riding on 6" wheels is not a big problem. The problems are two:
- it's very, very hard to pedal
- the sprockets will consume and become unusable after sometime

This bike will not last more than a few months. DO NOT BUY IT.

====================

Right now, what appears to be a good option, is the Dahon Jifo - the price is unfortunately high.

Big Shot Bikes Polo Bikes are interesting and rather small. It does appear these are discontinued now.

However, Mixie bikes and the Salsa Mini-Velo are other small bike alternatives.


Correct frame bike for me I’m trying to measure a cyclocross bike. I’m 172 cm, leg length 77.5cm.

Some websites like ebicycles say that my bike frame size is 53cm.

I’m already looking for this bike with seat tube 54cm.

A gravel bike that can be easily a touring bike for long travels.

What would be the problems of getting this bike?

Thanks!

There is no such thing as 'your' bicycle seat tube size, except as a very rough approximation. Bikes of different models and from different manufacturers that are specified as the same seat tube length say can actually vary quite a lot in size.

Seat tube length is a poor sizing system, and only really works to differentiate frames of the same model. This is why many manufacturers just use small, medium, large etc. The stack and reach system is much better, but somewhat hard for new riders to figure out an make use of.

All of that said, a 54cm bike sounds a bit to big for you. All of the bikes I've had are 54 or 55 and I'm a little taller than you.

Advice that is repeated by this community again and again is that you have to try out bikes for size before you buy. If you are buying from a local store, let the sales staff guide you. If you are buying used from private sellers you'll have to do a little research on bike fit and always do a test ride. If you are starting out and considering buying mail order from an Internet site - don't.


What are these eyelets for on my 2015 Diverge? I just learned a bit about Specialized's "Plug and Play Fender" that apparently fits my bike by way of metal rod into the leftmost hole of the first photo, secured by the set screw in the second photo.

This made me insatiably curious as to what the other threaded hole is for. The marketing materials I read before buying the diverge said that only the aluminum model had eyelets for a rack, and in this carbon model there's no eyelet at the top of the seat stays for a rack - just that one lower eyelet. It does not appear to be 1/4-20 thread, for what it's worth.

What could it be for?

The smaller hole is for  Specialized's proprietary "plug and play" fenders, while the larger is for a rear rack.  The larger hole can also be used as an alternate mounting point for other types of fenders. For a rear rack on the carbon frame Diverge, it is intended you use the Specialized Rear Rack Seat Collar (second picture), which combines a seat collar and mounting eyelets for a rear rack.


Replacement crankset for MegaExo BB 24mm on 8 speed bike I have a Specialized Allez E5 from 2017 with Shimano Claris (8 speed) and I'm looking to replace my crankset.
I believe this is my current crank.
My specific and potentially stupid question - am I right in just looking for replacements that fit my BB or is there anything special I need to consider for the 8 speed? I'm probably going to get a like-for-like replacement in terms of teeth, ring size and so on.
Thanks

is there anything special I need to consider for the 8 speed?

Yes, you specifically need an 8 speed crank.
8, 9, 10 etc speed group sets use progressively narrower chains, and the cranks have narrower chainring spacing to suit.
Many people seem to think you can get away with one speed difference and there are special shims available that adjust chainring spacing but it’s easier to just get a explicitly compatible crank.
Be aware that FSA MegaExo road (68mm shell) is dimensionally the same as Shimano Hollowtech II road, so you can fit a Shimano crank. Personally if I were upgrading to a Shimano crank I’d upgrade the bottom bracket to a Shimano unit also.


Why are riders allowed to draft behind cars in Grand Tours? During one of this week's stages of the Giro d'Italia, Richie Porte had a 'technical' issue with his bike that caused him to lose a number of minutes from the peloton. It was of significance as it was less than 10k from the finish and as a result was always going to be difficult for him to regain the time lost on the other GC contenders.

His team mates obviously did their best to pull him pack to the rest of the group. This included the whole team drafting behind one of the Team Sky cars for a period of time.

My question is: Why is this allowed?
Surely he/they are gaining an unfair advantage over the rest of the riders.

Addtionally:

Would it have been the same if he'd have fallen off 10k from the start line?
Would he have been allowed to do so if he was two minutes in front of the peloton when he crashed?
How is it decided what drafting is appropriate, and what penalties are handed out when it is deemed the riders gained some advantage they were otherwise unentitled to.

It is not allowed by UCI rules, but comissars usually allow it if it is due to mechanical reasons and used to get back to the peloton, since they have discretional ability to decide. Time penalties or disqualification if used to gain advantage over the peloton. So, rule enforcement may vary depending on many circumstances, and I guess they don't want to lose stars like Froome, that could also be important when turning a blind eye on some minor issue


Upgrading Gates CDN to CDX-EXP First of all I will start with the fact that I'm completely new to the world of hardware related to bike parts.

But I must say I ride my bike a lot. My everyday commute is roughly 40-50 km. I drive a Pegasus Premio SL belt 2019 and it is a city bike. I bought it almost 6 months ago. As of now, I have rode more than 5km with it. As far as my knowledge goes, it is equipped with a Shimano Nexus 8 speed hub with a Gates CDN S150 belt drive system. I don't know how many teeth I have in my belt (sorry).

Recently I saw that my belt started to chip its teeth away (of course wear and tear). Therefore, I'm planning to switch to a Gates CDX-EXP version to avail myself its robustness (at least that's what the website claims ;)). So, here I am.

I would like to know which combination of sprockets (front and rear) should I use and how many teeth should be in my belt and why. Moreover, I would like to know the meaning of teeth in the sprockets and belt. In addition, I would like to know whether I can use the re-use stuff from my old CDN S150 crankset.

This question is mainly because I tried searching for combinations on google but not with much success (I'm bit lost, because I haven't had much experience with it, yet). I of course read their manual, but it has different combinations and honestly, I'm a little bit lost.

Finally, I would like to have your feedback on whether it is worth upgrading.

regarding the amount of teeth on the sprockets/crankset:
 The ratio between the amount of teeth on the rear sprocket and crankset determines the gear ratio of the bike. Even though you have a gear hub the ratio between the sprockets will still determine your gear ratio. The smaller the sprocket in the back/the bigger in the front the higher your top speed is, but keep in mind it will take more force/less revolutions to keep your bike rolling at the same speed when in the same gear with such a sprocket ratio (small in the back large in the front).

check out the "gear ratio" section: https://www.whycycle.co.uk/buying-a-bike/bike-jargon-buster/bike-gears-explained/
general info regarding gears: https://www.sheldonbrown.com/gear-theory.html

If you want your bike to maintain it's current gear ratios either re-use the original sprockets or pick new sprockets with the same ratio of teeth (back/front).

the amount of total teeth on the belt should not really matter as long as: A) your belt isn't too short as in you cannot get it around both sprockets even when the wheel is adjusted so that it is the position most to the front of the bike as it can be B) your belt isn't too long as in you cannot get the belt tight enough with the available adjustment range (back to forth adjustment of the rear wheel) without the rear wheel falling out of the dropouts

A higher number of teeth on a sprocket means the force on the belt is distributed over a larger number of teeth. Which will reduce the wear rate of the sprocket and in theory also of the belt.

Regarding compatibility: This page suggests the CDN and CDX-EXP parts are compatible.
https://willem.com/blog/2018-02-24_creating-the-ultimate-commuter-bike/#continue

Judging from the story on the website above I'd say upgrading to CDX-EXP (especially the stainless steel instead of polymer rear sprocket) is worth it. As can be seen on the website the polymer sprocket doesn't seem to hold up all that well, especially when riding in harsh conditions.

This is after just 1800km according to the website:

CDN vs CDX-EXP sprocket:


Can I use a smaller bike inner tube than it supposed to My bike says I need a size 29" inner tube and I got a 26" wheel what’s gonna happen?

That's not going to work, you need an inner tube of the proper size for your wheel rim diameter and tire width.

The tire width should be printed on the tire along with the diameter. Tubes come in various width sizes that support a range of tire widths.

If in doubt, take the bike or wheel to the bike shop and let the staff pick a compatible tube for you.


Middle-aged child seat (Before I ask my question, please note that I am aware that "shopping questions" are not appropriate here. I'm trying to determine if a product exist, and if not, why, not to get a particular product recommended.)

tl:dr:
We are looking for a child-seat without foot rest and with 3- or 5-point harness.
Oddly enough, that does not seem to exist?

We have a Kona UTE 2104, with a Polisport Bilby seat on the back (fixed directly in the rear deck).
We are looking  to add a second seat, also fixed in the deck.

Ideally, we would like the seat to:

be a good fit for a 7 y.o., ~45 lbs (~20 kgs),
have a 3-point fixation (shoulder + between legs, i.e. a 3 or 5 point harness),
not have foot rest.

The reason why we'd like not to have foot rest is to be able to keep using the large frame bags on both sides of the bike:

If you could find a seat that did not have footrests or was advertised as holding a 7 y.o., ~45 lbs (~20 kgs) child it would not meet the ASTM International standard. It's over all safety would be questionable.

According to consumerreports.org:

  There are no federal standards for trailers or bike seats. The AAP recommends that any trailer or bike-mounted child seat meet the safety standards of ASTM International. Look for a sticker on the product or the packaging that indicates compliance. It's also a good idea to buy trailers and bike seats from reputable bicycle stores and manufacturers. Be careful about what you might find in toy stores, because those items might not meet the same safety standards.

If a child seat is manufactured according to the ASTM International standard:

  The carrier shall be manufactured free of burrs, sharp edges, and sharp points; when present, these shall be properly covered with protective coatings to prevent injuries. In addition, the carrier shall be equipped with a rear reflector, footrests, backrest, armrests, protective devices to prevent contact of hands and feet with moving or movable components of the bicycle, and belt or capturing devices to keep the child from standing in or leaving the carrier.

  This specification covers child carriers that mount to the rear of bicycles in order to transport children or accessory loads with a maximum weight of 18 kg (40 lb)

An option might be a tag along.
It also reduces weight on the rear wheel vs child seat and bags.

This rig would work with a rack and bags/panniers

EDIT:
Further comments indicate the need to carry two children.
A tandem tag along might be an option that reduces the inherent instability of a large weight high over the rear wheel and still accommodate bage.


Why do cable disk brake instructions say not to use the barrel adjusters? Most instructions that come with cable (aka mechanical) disc brakes say not to use the barrel adjusters on the brake levers.

Why not? Is there that much difference between the barrel adjuster on the levers and the barrel adjuster on the calliper?

As you dial out the barrel adjuster on the brake lever you pull more cable by effectively lengthening the cable outer (aka cable housing). By pulling more cable you change the starting position of the caliper brake arm, which if extreme enough, could mean:

the caliper brake arm may not have enough travel to get the full braking power; and,
If the caliper has some sort of progressive engagement trajectory, you start the contact point at a later point in the curve. (This was noticeable with early Shimano mechanical disc brake calipers, which would  loose initial brake bite.)

Either or both imply you are operating the brake outside of the intended design parameters, which means that the functioning can be negatively affected.

Adjusting pad engagement by using the adjustment knobs on caliper keeps the caliper brake arm in the same relative position regardless of pad wear thereby maintaining brake function throughout the life of the pad.


Should I apply pressure on the saddle during downhill on a rigid frame It is known that, while climbing, one should apply consistent and maximum weight to their saddle, in order to have precious rear tire traction.

The other day I was going down a dirt road, and the road irregularities and scattered stones, bounced the rear wheel maybe  up to 15-20cm in the air. My concerns are two:

loss of rear traction, while the wheel is in air
the saddle hitting me from behind, and throwing me over the handlebhars.

Should I attempt to apply some pressure on the saddle? In what way?

For example, I imagine that I can close my tights, thus clamping the seat and having some control over it.

No. If you sit on the saddle then you become connected with the bike. That means that the next hit from the ground will be transmitted as is on you and you'll most probably go flying in an uncontrolled manner, usually nose heavy, and you don't want that.

Apart from getting rest or pedaling, the only case where you touch the saddle is with your inner thigh (one, not both of them) in some offcamber cornering scenarios. But I think this is irrelevant to your question.

General rule for descending on rough terrain is:

heels down, applying max pressure on pedals (that's for flat pedals)
body in attack position
hands relaxed, ready to act as suspension
knees relaxed, ready to act as suspension
stay low
look ahead, not down to your front wheel


How to prevent cycling shorts damage from brooks swallow saddle? I am new to cycling and I have brooks swallow saddle and pair of cycling shorts. After the ride, I observed that the short's fabric is a bit damaged. This happened at the same place for both shorts. I don't know what exactly is causing this to happen. Can someone please suggest me on how to prevent this?
I also applied saddle cream after buying the saddle. This happened immediately after the first ride with both shorts.
please find image details here -
Castelli -
Gambitt -
saddle image -
EDIT- short full photo - https://imgur.com/C2eDcOX
EDIT - possible reason - https://imgur.com/QFWPNPB

I finally found the root cause after confirming the issue with the bicycle store. Also, I thank, @Andrew Henle for helping me out in finding the issue.
There are two reasons for my shorts being damaged with this brooks saddle.

My left leg is seaming inwards (arch is dropping inwards) while pedalling which is the reason, my left thigh is constantly touching the saddle front part.
My brooks saddle has a slight bulge towards the left side at front of the saddle, which has to be straight. And the friction due to this rubbing on leather is a catalyst in this damage.

The bicycle expert in-store suggested me to go for a non-leather saddle for now.