Mountain bike sizing for a short female This is similar to this question on frame size, however that is addressing it from a road bike standpoint.

My wife is 4' 9", and I am interested in getting her a mountain bike, as she has expressed interest in hauling the kids back and forth to local parks, etc, in a trailer. We had a child's bike previously, that was...clunky at best. It doesn't need to be full suspension (Truthfully doesn't need to be front suspension either, although I suspect there aren't any of those around any more).

The frame size charts that I've seen all stop at 4'11" for the shortest, with a recommended frame size of 13-15". Will that be sufficient, or will I need to possibly look at kid sized mountain bikes? Her body morphology is normal (No overly short legs with larger torso, etc), so everything is in proportion.

Proper bikes do exist in kids sizes, in essentially all types. 24" wheels are now common, which makes things easier. Some examples:

Ridgeback dimension 24" (hybrid as you said you don't really need suspension)
Specialized Hotrock 24" (hardtail)

Many of the major brands offer equivalents.  This is something where sticking to the big brands probably makes sense, as there's plenty of junk out there too.  These tend to be entry-to-midrange bikes (though there are exceptions) but unless the park is up a mountain or 10s of km away hey'd be more than adequate. Compared to the full-size equivalents you probably get slightly lower-spec gearing, but that can usually be upgraded quite easily/cheaply especially if done when the bike is being serviced anyway.  They're often in stock in big bike shops so test rides should be easy to arrange.

Compared to squeezing onto a slightly too-large bike (at a similar price point) you should get a lighter frame, and if you go for suspension it should be capable of being set up for someone of that weight.

A test ride is essential whether you go down this route or try for the smallest bike marketed for adults.

And a tip: getting moving with a trailer is harder than without; jumping up onto the saddle every start isn't going to make it easy.


What is the purpose of this rear dropout screw? I am a long time MTBer who just got my first road bike. This is a photo of the left rear dropout. The screw I'm talking about is the little silver one just above the axle. There is a groove cut into both the frame, and the bushing of the axle, to allow this screw to fit there. I'm guessing its just an anti-rotation device to prevent the axle fastener from backing out (or slipping during tightening), but I have had dozens of bikes of various kinds without this type of thing, so I don't understand why it's necessary.

It also bothers me that it doesn't sit perfectly straight when both it and the axle are tightened. When I start assembling everything it looks straight, but once everything gets tight it actually wedges itself into a slightly crooked state, meaning the actual axis of the screw becomes slightly off parallel with the axis of the screw hole, which makes me think the threads are being stressed unevenly.

While it has a rotation prevention value, it's negligible really. The Fuji Gran Fondo introduced this system in ~2012. They have a few of their road bikes use this convertible rear axle system.

This system allows riders to swap between a 12mm thru-axle and a 135mm traditional quick release system.
That screw specifically has a female part on the inside of the frame. They pull together through the frame to sandwich the axle receiver (black part in your photo) onto the carbon frame. - This is a common method for attaching interchangeable Aluminum parts onto carbon and is stronger than having a single screw driven into the frame itself. You also have the same on the other side and the sides need to interchanged as a pair. This is a common setup for convertible rear axle frames in both MTB and road.

Now, on the the 12mm setup the non-drive side receiver is round yes. However this side is more of a pass-thru receiver and the axle treads on the drive-side. On that side you have the hanger shape and another off-set screw that actually prevents the rotation as you tighten.

In short, I don't think you will ever be able to get that screw to seat perfectly flush (not 'crooked') with the way you have your axle inserted. By the looks of it in your photo, the axle tread in on the non-drive side at the moment. I would suggest that is the wrong way around. That could attribute to more forces being exerted on that side's receiver than what it's designed for. The carbon on that side also doesn't have any other features to assist with those forces (as oppose to the hanger bevel on the other side). Swapping it over might just get the screw flush, but you can still expect the screw to drift in the hole and not be centered in the receiver.

Also, typically these binding screws are further way from the axle center. So it may also be an effort to compact the design as well.

Pretty gif for clarification:


XT derailleur 1995 maximum teeth? I'm trying to upgrade my cassette for lower gearing on a Nishiki Continental. The previous owner put on a (NOS) Shimano XT rear derailleur. I use friction shifters.

I looked on the back of the cage and the models says RD-M739. The document from Shimano says 32T maximum. What do you think, would a 34T 9-speed work?

I would like to have a bigger rear cog so I'm asking just to be sure it's not a RD-M739-SGS. How can I tell? Would SGS be stamped on the back if it would be?

Thanks!

Update: I actually found a 7sp overdrive with a 34T largest cog on another bike that I tried. Seems to work just as fine as on the bike it came from.

I just mounted the 34t cassette and it works fine.

I also tried it on an even older but same length DX derailleur and it worked there as well. Only using it for road and not MTB. Not sure if that makes any difference.


Adjusting wobbly handlebars This is the bicycle that I own:

My problem is that the handlebars have become loose right right where that red bolt is located. There is an identical bolt on the other side. I have tried adjusting them but they won't budge.

Does anybody know what these kind of handlebars are called and how they can be adjusted?

I have two bikes with this kind of adjustable stem for handlebar. It is using a simple "tooth" that hold it on position. If it is not tightened properly, the tooth will be grinded down and become lose after sometime(that cause the wobble).

To check it out, you need two wrench(with hex bits) or hex key. Wrench with hex bit is recommended, because it gave you enough torque to twist open the screw. One side turning at opposite direction while another holding the screw from turning.

After you loosen the joined screw,  you will know what I mean. Now adjust the handlebar and make it "locked" properly, then tighten the screw. Make sure you make it very tight (I don't have an expensive torque wrench to measure the torque) when you place the screw back.

(UPDATE)
The funny part of these kind of adjustable stem, is the "lawyer notes sticker" mentioned in Sheldon brown hands up article. Both of my bike come with this sticker.  I have better quality adjustable stem on my touring bike, which you don't need much force to tighten the screw and only one hex key is required to adjust the stem.

(Photo borrow from Sheldon Brown website, http://www.sheldonbrown.com/handsup.html )


Why are rear wheels dirtier? I have noticed that my rear wheel is always considerably muckier than my front one, after a wet commute.

Why should that be? They both travel the same distance and terrain. I assume this is a common experience.

Bike has mudguards.

As mentioned in the other answers, there could be several reasons that your rear tire is always muddier than the front after a wet commute.

The front tire splashes mud on the rear of the bike.
There is more weight on the rear tire, causing it to sink deeper into mud.
Your power is being transferred to the rear tire, creating more friction than on the front.
You're probably using your rear brakes, causing your rear tire to slide.  If so, it's probably better to use more of the front brake.

One more thing... the mudguards are probably not keeping your wheels and tires clean.  They're there to keep you from getting splashed.


What things to check on road bike after a long trip on poor roads Just bought a new aluminium frame road bike with 25mm tires. Due to very poor planning, I started a journey that turned out to be suited for mountain bikes: it involved country roads, unpaved gravel sections, some parts that were paved were more potholes than asphalt. After a pinched flat (because of the very poor paved sections), skidding 3 times and barely making it out, I decided to call it a day midway, and 45 exhausting kms(28 miles) spent.

Besides a very sore bum, I am wondering what other things maybe have suffered. What things should I check on my bike to see if anyone is broken, shaken, what things might turn loose, what areas are susceptible to paint being chipped at, what things to pay attention to on my next ride (which will only be on smooth roads), etc

I think road bikes are actually more durable than a lot of riders give them credit for. Unless you were seriously crashing into potholes there should not be any damage (although you may have picked up some paint dings from loose gravel surfaces).

You can do a standard 'once-over', paying particular attention to the wheels:

If the dirty or muddy give it a wash and clean and re-lube the drivetrain and chain
Check drive-train and brake functionality
look for rattles and anything loose
Check for play in headset bearings
Check the rims are true
Look for dings in the rim flanges and scratches in the braking surface.
Check there are no loose spokes.
Check for damage to tire tread or sidewalls


My chain slips despite new parts and tuneup I use my bike for commuting, and so my knowledge of bikes is enough to make to work and back.

I have a trek 4500 mb. I purchased it used, and from the very first day I have had this issue where the chain slips/jumps. Which means, peddling is far from smooth.

I've already:

tuned up bike (several times)
replaced chain
replaced cassettes
replaced crankset
replaced derailleur (rear)

But the issue persists. Slipping happens every day, at least once a day, but often when I create more torque.

What could the issue be? I like this bike, but the random slipping is rather dangerous as sometimes it happens when I'm standing. I have 2 bike shops near me, neither can give me answer or fix the issue.

I presume all the new drivetrain parts were replaced close enough together that they were all new or new-ish at the same time. If on the other hand just the chain was replaced, the cassette or rings were highly worn, you rode anyway for some time (say a few hundred miles), and then replaced those too, it's possible you could have put enough wear on the chain in that time to keep the problem going. You can measure the chain wear with a ruler to test this.

Misaligned rear derailer hangers and/or cable housing friction can both cause this and unfortunately can be missed by shops. If that were what's happening, shifting would be poor too.

In an extreme case, rear frame misalignment can cause this. You'd probably be able to see it though.

The other thing that can do this is issues with the ratcheting mechanism inside your freehub or freewheel, which can also go unserviced at shops. The common scenario is the lubrication at the pawls gets gummy or depleted, keeping them from popping up with adequate force to engage properly with the driver or drivering (arbitrary terms for whatever toothy bit the pawls mate with). Or a pawl or pawl spring can be broken or out of place, creating the same problem. Then sometimes as you pedal, just the tip of the pawls might be engaged with the teeth, which feels solid until it slips under load due to incomplete engagement. The sound and sensation is very similar to chain slippage.

If that is what's happening, one problem is hubs can't take too much of it before the pawls or driver get damaged and can never work right again.

You could diagnose this by subbing in another wheel to test, or by getting someone to watch the skipping as it happens and confirm its the freehub turning and not the chain slipping. With experience one can make pretty good educated guesses about what's happening inside a freehub body by manually back-spinning it with the cassette off. Sometimes you hear tinkling or crunching inside and it's less of a guess.

Fixing it depends entirely on what hub it is. Usually the first step would be get some lube inside and see what happens. Some hubs make it easy to take the whole thing apart, but many do not.


Winter commuting - how to keep warm? I am interested in what the best ways are to keep your face and feet warm.

I saw some shoe covers on amazon, but they all seem to require you to be riding clipless which I do not. I think if I used a shoe cover, the bottom of it would get all ripped up by the teeth of my pedals.

The face is another challenge I have. I usually like to use biking glasses, but recently I started using a balaclava which covers my nose and mouth. As soon as i started breathing my biking glasses started fogging up! Is there a balaclava solution that works with glasses?

keeping your face warm while winter bike commuting

I recommend ski googles and Seirus "Masque" over a balaclava. This mask only covers the bottom half of your face, and can be paired with merino wool hat worn underneath a helmet. This is more versatile, as you can remove the mask, but still wear the hat off-bike. I also use a scarf underneath my jacket to make sure there's a good seal to keep the wind out. For my kids, I still use a balaclava for simplicity on very cold days.

keeping your feet warm while winter bike commuting

For keeping your feet warm, I recommend NEOS overshoes. They go over your normal shoes, keeping your shoes and pant legs dry and clean. Even the non-insulated options add warmth due to the layering. I like the Voyager model, which is also light and packable.

Keeping your hands warm while winter bike commuting

If putting your hands someplace warm doesn't work well enough, you can try a little cayenne to improve your circulation. A small amount can go in your gloves (or socks!) It has worked for me. This worked for my son:

I have another number of other winter cycling articles on my blog if you'd like to read more about my experiences and gear.


Two brake positions on fixed gear/single speed I recently bought a fixed gear/single speed with a flip flop hub.
It has drop bars with two brake positions. One on the hood and one set of cross top brakes.
I was considering removing the hood brakes, as having two sets looks a little silly (to me) on a fixed gear.
I don’t know if the bike was originally a conversion or if it came this way.

Would it be okay to remove the hood brakes and keep the cross bar brakes?

I do hope I worded everything appropriately! Thank you in advance for your advice.

You can use cross top levers without the main lever with some hacking. There is a thread about it here: https://www.bikeforums.net/singlespeed-fixed-gear/108969-how-install-inline-brake-lever-primary.html

You can also replace it with a 'normal' brake lever. If your bar is oversize (31.8 mm) it can be hard to find a brake lever that fits, but it's certainly doable.

Having two levers might not be such a bad idea though, since it means you have a brake lever within reach from all hand positions. But I'm planning on installing just a 'top' brake lever on my fixie, so I can certainly see your point. You can also put a TT bar end lever at the bottom of the drop and use the cross top lever as well. That will look 'cleaner' than the usual road hood thing.


Need new crankset for a 15+ year old bike [chain slipping on gears] Just discovered this site. My uncle gave me his old bike. The chain has been slipping and today we replaced the chain (previous was worn and stretched, the rear casette (to a used but less-worn one), and the two cogs on the derailleur. Now we can definitely see that the chain is slipping on the crank -  on the front, not the back gears.

Could you all please help me determine what kind of new crankset I need that will fit best?

42 teeth in the largest

Pics here: https://imgur.com/a/SHgDQEo

If you just want to go with something basic that's close to what you have, it's easy to get a replacement repair type crankset for this sort of bike. Check your tooth count, but it's probably 42/32/22, and then check the length, which is usually stamped on the inside of the arms. It will probably be either 170mm or 175mm.

The other distinguishing factor is that what you've got is a "low profile" type square taper crank, which is bike parts catalog lingo for "the arms are all bendy," as opposed to flat. They were the predominant type on 90s steel MTBs such as this. Square taper low profile cranks usually use the shorter range of bottom brackets, i.e. 115mm-ish, so if you want to re-use the existing bottom bracket, you'll likely need to get something similar.

However, that leads to the real rabbit hole: matching the bottom bracket. You want your front chainline to come out right. Different cranks use different length spindles to get to the same front chainline. Presuming the chainline is good now, and if the bottom bracket is in a condition that's worth re-using, the best way to proceed is pull off the existing cranks, measure the spindle, and get a replacement crankset that happens to take the same length according to its manufacturer specs. There's a further stipulation here that this bike could be old enough for its rear end to be a little narrower than the 135mm standard that was ubiquitous on mountain bikes from about the mid-90s on. Or not - doing this right would entail measuring. There are a lot of questions on this site about measuring chainline that can help you figure this out. Published BB numbers for the type of repair cranks you'll be looking at will be to give a modern front chainline of about 47.5mm, so if your target front chainline number is different for any reason then you'll have to compensate in how you interpret the listed spindle length.

If the existing bottom bracket is fairly worn and you think this bike is going to start being ridden again, replacing it with a decent cheap new one like a Shimano BB-UN26 probably makes sense because they're so cheap. If you want this to be a minimal cost repair, then do the above.

All that said, if you just search around for "42/32/22 square taper crank" you'll see tons of options.


RS Revelation '11 dual air fork leaks I have a RS Revelation dual air fork. It's new, never used before. I installed it and after a few days I noticed, that it loses air. Maybe 20-30 psi over night. So at morning it's just too soft and have a sag around 40% (way too much).
Air leask from both positive and negative chambers.

Is it normal for this fork or should I check any specific parts of this fork?
Please note, that there's no RS service center in my city or anywhere nearby and I would prefer to fix problems (if any) by myself.

I have never had experience with an RS Revelation fork, but you might find this forum post useful. Common solutions seem to be taking the fork apart, cleaning, and re-oiling the o-rings. Good luck!


Suggestion for rigid fork to replace 100mm-travel RST suspension fork on 26" Trek 4300 MTB? I have a 2008 Trek 4300 MTB (v-brake version) and am looking to replace the RST 100mm suspension fork with a rigid fork, but am having trouble finding something suitable.  I measured the fork length to be roughly 19 3/8" (~492mm).  All the rigid forks I've found (Surly 1x1, Sunlite) seem to not quite have the a long enough fork length.  I'm hoping someone here might have a suggestions.  Thanks.

That is a very big axle to crown number for a 100mm 26" fork. 490s for 26" is more associated with dirt jump/downhill/etc, hence the lack of options you're finding for a mass produced rigid conversion fork. What you'd want if you could get it is something around 465-470mm, which represents what the front end ride height would be with around a quarter of the travel used up statically, which is kind of the baseline rule of thumb that manufacturers go by to figure out what the axle-to-crown is going to be on their rigid conversion forks. Most 100mm 26" forks, say an F100 or Reba, were in the 470-475 range, so most of the rigid conversion forks for that sort of bike are around 445-455. It's all a game of approximations.

There were a few rigid suspension corrected canti post forks in that era that were kind of in the dirt jump/"BigMX" genre, with long, heavy, non-tapered chromoly legs. There was a Redline one in particular I'm thinking about that I'm unable to find numbers on currently, but I wouldn't be surprised if it was longer than everything else. It was very long and heavy.

If you can find a 1x1 canti fork, at 453mm they're on the longer end of what exists for this. That plus a 10mm extender headset lower gets you about where you'd want to be - maybe a little shy if the bike really is designed around a 492mm fork, but it really shouldn't be a big deal riding. Even without the extender it would still be perfectly rideable, but the rider position change would probably come into play more.


Number of gears for a racer I am looking to upgrade my racer, I currently have a Bottecchia racer from the mid-80s and it has 14 gears.  While looking around for newer racers I noticed that a number of them had 20 gears while other ones had 27 gears.  Since I live in Berlin, so pretty flat although with the occasional hill, what would be the recommended number of gears?

Bikes which have 27 gears will have triple chainrings at the front. Three rings can be very useful to give you lower gears, typically when you might struggle at climbing, or carry a load such as when touring. For example, I have an Audax bike which has a triple chainset. Its by no means a thoroughbread in terms of performance, but its suitable for a wide range of rides including multi-day trips.

However if you're looking at a "racer" bike, it is far more common to find just a double chainset at the front. In fact, many manufacturers produce double chainrings which will give you almost the same range of gears (but not quite) as a triple - these are called compact chainsets.

A double chainset will be what gives rise to your existing 14 gears (2 rings at the front, 7 cogs at the back), or the 20 gears (2 x 10) you've seen. In fact both Shimano and Campagnolo (I'm not sure about SRAM, but these three manufacturers dominate the market) now produce 11-cog rear cassettes, which would give rise to 22 gears. But 11-speed cassettes are at the high end of their respective product ranges, and 10-speed is far more common.

Note that while a triple chainset will make climbing easier, that's not to say that climbing is not possible with just a double chainset. Far from it. You'll probably find that most seasoned cyclists (and all professional cyclists I think) will ride with a double chainset.

So in summary in a place with occasional hills, a double chainset will probably suffice. But definitely worth considering the "compact" option too to give yourself maximum flexibility.

Example

The current Shimano Ultegra chainset comes in triple, double and compact variants.

The triple rings have 52, 39 and 30 teeth.
The double rings have 52 and 39 teeth, so basically the same but without the smallest ring. You can imagine this might make climbing quite a bit harder (30% to be precise) on your legs
The compact has rings with 52 and 34 teeth. So the same "high gear" limit, but a smaller second ring to make climbing easier. Clearly the small ring isn't as small as the triple, so the triple will give you the easiest gears, but as I say compact is "enough" for most of us.


V Brake Arm Stuck on Post I picked up a frame a week ago and the guy said that he had it for about a year or so. And he told me that both brake arms were stuck on the brake post. But I tried so many ways to pop these suckers off but nothing worked. I can also see grease on the bottom of both arms so maybe too much grease on them was the case? I never really work with V-Brakes too.

That's an indication of possible crash damage, because the brake arms have bent and distorted their mounts.  However your photo shows rear mounts which are rarely damaged this way.

It can also happen if someone deforms the mount by using the wrong bolt, or over-tightening it and deforming things.

You may be able to use a small automotive bearing puller to pull the brake arm off.  A couple of flathead screwdrivers can help provide leverage.

Another moderately good help is to warm the area with a hairdryer on high.  This may be hot enough to damage plastics, but shouldn't damage paint.  If the frame is carbon fibre or  aluminium alloy then don't try heat, but it works nicely on steel.

Last resort is to cut the brake arm off using a dremel and small cutoff wheel.  Its very hard to avoid damaging the mount posts though.

Crazy thought - have you tried backing off the spring tension adjust screws?  Not all the way out, perhaps 10-12 mm.

If the tension springs are somehow locked in a groove or something, this might help.


En masse bicycle commuting The area I live (NE United States) doesn't have a very large infrastructure for biking. There are scattered bike paths and they've finally completed a bridge that allows me to commute to work, but there's nothing like these in London or this one in Denmark. In fact, most of the time I'm sharing roads with typical American drivers ("Ooh! Look! A bicyclist! Let's swerve into him! I won't even have to put the cel phone down!"). In general, I like the solitude and the fact that often I'm the fastest vehicle on congested city roads (nothing like zipping by a line of cars stuck behind a clueless driver) but I've started wondering lately what it's like riding with a lot higher volume of other cyclists on the road. In general I avoid the bike paths in the area on the weekends because there's a disproportionate number of folks who seem ignorant of riding etiquette (slower traffic keep to the right, don't let your children lurch blindly into the path of other cyclists, etc.) but these aren't regular commuters.

Folks who ride in areas with much better infrastructure (doesn't even have to be a bike "superhighway") - do you find that higher volumes of commuters mean a worst commute for you personally? Does having a larger commuter "culture" help with other riders or is it just as frustrating as being stuck behind them in a car as they apply lipstick and chat away on the cel phone?

EDIT: based on some discussion below, an additional (yet related) question - are there considerations built in to the larger bikeways to allow riders to keep a faster pace (i.e., multiple marked lanes)?

It all depends on the riders that you encounter, actually. I've been in group rides of 40+ where everyone was an experienced cyclist, and it was smooth sailing. People were able to move in and out of various parts of the group at will, road safety and laws were observed, etc.

I've also been in rides with 6 people where the handling was sketchy, they spread out across the road, ignored traffic laws and it was generally not a pleasant experience.

The "commuter culture" is pretty much going to be just like the car commuters. You'll have quite a few that obey the laws and operate in a safe manner, then you're going to have the few that ignore the laws, people around them, and generally make it unsafe for everyone else. My favorite lately was a college "hipster fixie" rider that was riding no handed, cigarette in the right hand, cell phone glued to the ear with the left.

Operate your bike in a safe manner, watch out for the cars and the unsafe riders, and you should generally have a pleasant commute (And yes, there is nothing better than zipping past a long line of stopped cars! :D )


Should I replace these cassette and chainring? I saw my bicycle chain very dirty so after many months since last time I cleaned it and I checked the general state of the drivetrain. I totally forgot that a couple of years ago the chain was already somewhat stretched.

I found what looks like a very worn out chainring, a very stretched chain and a cassette in a mixed state.

Chain is 1.8% elongated.

Chainring:

Cassette: it looks like the 2nd sprocket is the most worn out, the 1st, 3rd and 4th not so much. It is a Maillard Helicomatic so I cannot easily find new sprockets, and probably not new in any case. I may need to replace the whole wheel. I wonder when this bicycle has been manufactured...

Which parts is good idea to replace now, given the actual status?

That chain should have been changed ages ago - at or before 0.75% ideally.  At 1% you will need a new cassette.  To get to 1.8% is astounding, and means that the cassette and chain have worn into each other,

The chainrings look OK, because there's a lot more teeth engaged compared to the cassette, however if the chain slips at the front after replacing chain and cassette, then the chainring needs doing too.

You might also want to examine your two jockey wheels and consider replacing them.  The main difference of that is improved shifting and little to do with skipping, but given the rest is that worn you may as well change all the wear items.

Keep your chain cleaner too - that's a contributing factor on transmission wear.

If I were you, I'd give the bike a proper refresh.

New brake and shift cables, inners and outers
New brake pads front and rear
New bartape

Depending on wear you might even consider new tyres and saddle, but they're more expensive so not a priority item.

Give your bike a proper clean and degrease (that means using an old toothbrush.   While doing so, examine the frame for cracks and any damage that was hiding under the dirt and oil.


seat tube deformed, is it dangerous? I just bought a 2nd hand salsa El Mariachi frame, that I will start to build this week.
Unfortunately when I received it I realized that the previous owner probably has ridden it with the seatpost too high or inserted only a few cm and I noticed that the top of seat tube is deformed, have a look at the picture.
Do you think it is safe to ride? or might break?
suggestions?

thanks for your input

It's probably fine, especially if it's 4130 or something similar, as opposed to a heat treated and/or air hardening tube.

From one picture and without hands on it I wouldn't necessarily recommend this, but such damage on steel frames can often be more or less repaired by putting in a stout seatpost of the right size, wrapping the area in a rag, and going to work on it with a rubber mallet. One good reason to do this would be if the deformation was partially bulged inward and the seatpost wasn't moving very freely, or making bad contact and tending to slip.

It appears that there would be room to cut off the end and extend the slot, but since the deformed part in the picture isn't at the top anyway there probably isn't much point. If you were finding that a seatpost goes in rough because the whole top part of the seattube is bent backwards, then this could perhaps make sense. It's critical you preserve a long enough slot in order for it to be able to clamp. Framebuilders have a minimum slot length worked out; I've seen it mentioned but I can't find it right now.


Touring on a Tri bike? I'm going on a coast to coast tour, fully supported, so only carrying what I need for the day.

I have a Trek Speed Concept I have used for Ironman races and a few multi day tours (75 mile days).

I used a touring bike with a triple for a similar ride a few years ago. It was great in the mountains (and for being new to riding at the time), but felt slow the rest of the time. Really wanting to take the Speed Concept on this ride...compact crank with 11/28 cassette, Thoughts? Am I nuts?

It depends entirely on what your are trying to accomplish and what your expectations are.  Many RAAM riders opt for a TT style setup, so don't let the long distance dissuade based on "it's not done" that way, because it is (by some riders).

A large consideration may be parts and maintenance.  Most traditional touring bikes opt for simpler parts that are easy to repair or find replacements for.  I saw a guy attempt a similar thing on a TT bike starting up north on the Haul Road and planning to finish in South America.  He crashed soon into his ride and needed a new derailleur hanger and bar end shifter for his fancy bike.  Since the hanger wasn't available in town (direct from manufacturer part) our mechanic had to fabricate him a hanger out of scrap.  For the shifter, nothing (within reasonable expense) could be done.  He was forced to call ahead to a shop in Canada and hope they could get one ordered and available by the time he got there, then ride without it for several hundred miles.

Also, from commentary from links on another answer, tire selection may be impacted.  Depending on the rear tolerances on your TT bike, your selection of tires may be limited to less than desirable tires for touring.

The point being that TT bikes tend toward extreme specialization and part styles that aren't often carried in stock.  As long as you are aware, careful, bring your own second TT bike, or comfortable with the possible delays (or some combination of the 4) it may be fine.


Never used a repair stand before. Wondering how much they can handle So, I've started to look into buying a bicycle repair stand.  I've never used one before, and I was just wondering if people keep their bikes clamped while really torquing down on a bolt, and trying to get stuck ones off.

I'm interested in going for a bottom of the barrel stand first, but most of them have plastic connectors that connect the clamping arm to the long vertical post that goes down to the ground.  I'm afraid that if I push or pull to hard on the bike, that the plastic part on the stand will break.  Is this a legitimate concern?

Are stands only meant for 'delicate' jobs, or can you leave them in for things like bottom bracket removal too (that often require a lot of force to remove cups)?

Also, doesn't the bicycle 'dangle' and move side to side a lot in a stand since it's only clamped in one spot?  I just imagine trying to tighten/loosen a bottom bracket cup, and the bicycle moving a bunch laterally.  Does this happen?

Thanks everyone.

The load limit is determined by the stand rather than the clamp in all but the cheapest setups. If you look at what bike shops use they tend to have great big chunks of steel with clamp arms bolted to those. But those clamps, even the really good ones, cost about the same as a cheap clamp with stand. So the question to ask right at the very start is whether you're better off buying the proper tool right at the start.

In both these photos (search for "bike mechanic" rather than "bicycle workstand") the key point IMO is that there's a nice solid bit of steel pipe holding the clamp up, and if you look around that pipe is normally bolted to the floor. Where I worked we used slightly thicker square tube with a clamp each side (two mechanics per pole).

 (via Boston News)

 (via JobMonkey)

That setup will be more expensive that a cheap portable stand, but a lot more effective. Find a local steel fabrication business, tell them what you want, say you're willing to wait until they have time to put one together, and it shouldn't cost too much. Most places will be able to make it from offcuts, and it's an easy welding job. What you want is thick wall mild steel square tube somewhere between 70mm and 120mm on a side and 5-10mm wall thickness, between 1.5 and 2m long. Weld that to a bit of plate about 400-600mm square and 8mm-15mm thick. The reason for the loose dimensions is that you are aiming for "what spare bits do they have", if you specify it exactly they will cut it for you and charge accordingly. So that post will cost between "some beer" and "$300 plus tax", depending.

I used to use a simple length of square tube with the clamp on it, and I'd put that in the vice on my workbench. But that was a 6" engineering vice that weighed 30kg, bolted to a 100kg steel framed workbench. If you have a bench like that it's a great way to get an easily moved out of the way stand.

 (via Mσᶎ's awesome Paint skills)

A stand like that will hold an electric assist loadbike without problems once it's bolted to the floor. With a bigger plate you can avoid bolting it down, but it might fall over if you don't pay attention (and it's heavy enough that if it falls on your bike it will seriously damge the bike, or you). Lifting a heavy bike into the stand, on the other hand, will be a hassle. My local eBike shop uses powered hoists for that reason.

A cheap stand will be very flexible, and even if it doesn't actually collapse, it will feel as though it's about to even with a lightweight road bike in it. When you want to apply any real force to the bike you will need to brace the bike against that force as well as applying it. Which is a huge pain. That said, they do work for most minor repairs and adjustments.

But the stand is cheap and it folds away to nothing. Hopefully when you want it to fold, but for that price you can't be too fussy. What you're buying there is light and easy to fold, you're not paying for a usable workstand.

A better lightweight design is this style:

They support the bottom bracket rather than the top tube/seatpost, so there's less stand to flex. It's slightly more twiddly to get the bike in and out, but they're easier to work with in my experience. At least for upright bikes - it's unlikely that a recumbent or load bike will fit into them at all.

edit to add:

Finally, many "bike storage systems" actually work ok as workstands. The ones that suspend the bike from the roof using pulleys are very close to the power hoist that my LBS uses. Many of the "arms poking out from the wall" style have arms long enough that you can pull the bike out a bit and spin the pedals while the bike is on the storage unit. This style of leaning hanger is available pretty cheap if you can put up with less decorative versions:

With the "wall hook" style that hang the front wheel it's less convenient, but you can put a block under the bottom bracket to push the rear wheel away from the wall and adjust the gears that way. Reaching the handlebars when the bike is hung up is only easy if you're tall, though, so it's not always an option.

Many car racks can also be used this way.


Hydraulic Disk brake piston not fully retracting My front disk brake's piston doesn't fully retract.  While I can ride the bike, the brake is slightly rubbing.  (IE, if I just spin the wheel with my hand, it'll go around about one and a half times and then stop.) It's definitely slowing me down.

If this fixable?

The advice I got was that it's not worth the trouble and to buy a replacement set.  The current brakes are Avid Juicy 7s that are about 7 years old

I would try repairing them before binning them and purchasing the Shimano upgrade. If there is no obvious fluid leak around the piston the seals are likely in good order and you've got a sticky piston rather than a failed calliper. This is a simple fix:

Remove wheel and brake pads.
Using a flat headed item hold the working piston in.
Squeeze the lever, the non-retracting piston should be fully out.
While holding the lever wipe around the piston with a clean lint free cloth.
Still holding lever lubricate the retracting bit of the piston with a bit of brake fluid (DOT 4 or 5.1, not oil, as this may damage the seals and/or might work through the seals and mix with the brake fluid)
Release the lever and repeat lubricating 5 more times, the piston should now be retracting.
Wipe off any residual brake fluid from the caliper.
Use a brake block to push both pistons evenly back into the caliper. Pull the lever with the block in to align.
Refit the pads and wheel.
Realign the caliper.

Please note, never pull the lever when there's nothing in between the two pistons. It's hard to separate pads and near impossible to separate pistons without bleeding.

Juicy 7s were good brakes, if they aren't broken there's no point rushing out to replace them.


Source for statistics from pro cycle races I've been searching all over the web for statistics from bike races, starting with the Tour de France because it is the largest. Stats I have been able to find include each stage's winner with their time. I'm just wondering if anyone knows a good resource for pro cycling stats like time per km or per segment within the stage. I'm pretty curious about the riders performance at certain parts of the stages.

Depending on what you're looking for, a site like trainingpeaks.com might meet your needs. You can often find power meter data files for riders collected during both the Grand Tours (the Tour de France, the Giro d'Italia, and the Vuelta a Espana) as well as many one-day classics (like the Ronde van Vlaanderen (the Tour of Flanders) or Paris-Roubaix). From these data you can extract speed, power, cadence, gear ratios, pedal force, heart rate, and slope over different segments of a race. In certain circumstances you can estimate aerodynamic drag and other parameters of performance.


Can you add oil to a hydraulic disc brake reservoir without bleeding the brakes? Is it possible to add oil to the hydraulic disc brake reservoir to increase the stiffness of the lever, without bleeding the brakes?

There are 2 types of hydraulic brake systems, referred to as open systems and closed systems.

Open systems have a reservoir, with a cap, usually on the brake lever, above the master cylinder.  These systems, when proper care is taken, can have fluid added, or hoses trimmed without rebleeding the brakes.

Closed system brakes, like most older Hayes brakes, (HFX-9, Nine, Original Hayes) can't add fluid, because the only access to the fluid reservoir is through the bleed ports.

Whether you can add fluid or not, if your brakes need to be bled due to water or air contamination, then simply adding fluid will not fix your problem.  If you have a simple fluid leak, with no contamination, then it may work, although you should also look for the source of the leak, and fix it.

Bleeding a brake is not a difficult task, and usually requires few, if any special tools.  If your brakes need to be bled, look up the manual, and give it a go.  You can't really do any permanent damage, and if you follow the directions, you shouldn't have any trouble, anyhow.


How to calculate elevation gain for a route not recommended (by Google) for cycling I have a need to figure out elevation gain on a (United States) freeway (to compare options) to plan a cycling route. Google will NOT allow me to drag the points into the freeway route if cycling is the transportation method. If I switch it to a driving route, Google will not give elevation gain stats.

It appears that if a route is not recommended for cycling, Google will not let you route it (which I realize could be hazardous otherwise). IMO, it should only give a warning and let users make their desired route.

Anyhow, is there a way out there to get elevation gain stats on road/routes not recommended for cycling?

After some thought I feel strongly that this question is in the correct context here. True it’s a question also about software, but I doubt the software user base has as much to offer it as cyclists do.

Whether or not it’s legal or safe is a bit irrelevant. Google’s safety and legal limitations are just examples of why I might need such a feature. And we know that software, the law, and road and highway planning aren’t perfect. For the purpose of just finding out if such a feature exists somewhere on this planet, we’ll say I’m using my best judgements about safety, and would not do something I felt was a risk for myself or others. Safety is another primary goal in using our own judgement for considering all possible routes. The law may in some cases be wrong, or many not regard changing conditions such as weather or road construction, and direct us through a more dangerous route. Also, say we’re out on the road and there’s some sort of emergency; elevation may become a critical consideration in finding the best way home.

I highly recommend https://brouter.de/brouter-web for bicycle route planning. It also calculates elevation gain/loss and tries to avoid elevation changes.

Keep in mind that elevation data can be inaccurate since it’s usually using Digital Elevation Models which are based on satellite data. For example it might miss things like bridges entirely and display a huge elevation gain/loss for crossing a gorge. See https://brouter.de/brouter/elevation.html


Damaged paint on fork dropouts (magnesium) – is it dangerous? I've noticed that paint on my Reba fork peels off near quick release dropouts. The lowers are made of magnesium according to RS website. Should I regard it as a cosmetic issue only, or is it in any way dangerous? There are no other damages.

How can I prevent it from peeling off further?

Note: edited to include information about material.

It probably won't peel further (you can apply whatever paint you want around the edges if you want), but the issue is just cosmetic.

My suggestion is just to ignore it and move on with life.


Single speed chainline I have just finished my first fixed gear based on an old Raleigh Rapide frame. But the chain line is off and I hear a crackling/ticking noise when I pedal.

The wheels are replace with a gipiemme wheelset and I kept the old bottom bracket and crank/chainring combo. The chainline is off by a few milimeters.

I have created an image that shows the issue:

My first guess is to replace the spindle/axle. Are they sold seperatly from the cups? The current spindle is asymetric (longer on the driver side), but for a single speed bicycle I could probably buy a symetrical one right?

How can I find out which spindle I should get?

What other options do I have?

I would surely go by changing the bottom-bracket for a longer one (be it changing the spindle as you said, or installing a sealed Shimano-type one).

If you don't want too much to keep your current bottom bracket with separate spindle and cups, the sealed one is much more reliable, long-lasting, play-free and water-resistant.

To find out the correct size is not a trivial task, I think you should go talk to some friendly and experient bike mechanic, since there are some subtle factors involved in bottom-bracket crankset interaction, that determine the final position of the chainring.

If your spindle looks long, get a shorter one and move the ring to the outer side of crank spider. If your crank is already very close to the frame, find a longer bottom bracket.

OR

You could play with the wheel/cog position,sometimes there are washers and nuts around the bearings that can be moved, swapped, changed for thinner/thicker ones, etc.
I have a fixie with a very cheap rear hub, and there is a lot of dishing, but I don't care, I've ridden dished wheels my whole life and they worked. It is not prettiest, but it is a minimal problem compared to twisted chainline on fixies/singles.

Hope it helps!


Crate of beer as cargo I recently bought a two wheel cargo-trailer without suspension, and I am quite happy with it.

My main issue is that it gets incredibly loud when carrying a crate of beer, especially an empty one.

Is there a trick to keep the noise down? I tried to wrap the crate in towels, but it does not really help.

Edit

Cardboard-dividers did not change a lot, compared to my towels. They did look pretty cheap, there might be better ones.

Tilting the crate 30 degrees in the trailer however, reduced the noise level substantially.

buy cases of beer with the cardboard dividers between the bottles.  You can then re-use the cardboard dividers in other cases of beer.


Could I replace a hub on a wheel? I have a freewheel and I keep bending the axle, however the rim, spokes and tire are all fine, does anyone think it would be possible to unscrew the spokes, buy a new hub that has a freehub, install that with maybe new spokes and my previous rim? (And also buy a cassette) because I don't see the point in buying a whole new wheel just for the hub.

Simple answer: yes, but it’s not worth doing.

Cost of hub, spokes, nipples and having wheel rebuilt will exceed the cost of a new wheel. Even if you re-use the spokes a new wheel will still be cheaper.

Wheel building requires special equipment, expertise and time to do correctly.


FOX FLOAT CTD Evolution oil leak :( I have a FOX FLOAT CTD Evolution LV 184x44mm, which worked fine in the summer, afther the cold weather arrived, and I started to ride under 15C, it started to leak some oil. It was pretty nasty, but I wasn't able to do anything, my bike is stored in non heated garrage, so it can get pretty chilly out there, -5C.

Now the temperature started to rise, so I bought a service kit, with seals, and a friend of mine, came by to replace them, like on this video

But even after this, the oil leaks like there is something broken. The shock still works fine, it has 3 modes, and the lock still converts it to a hardtail, and the folly open, gives a nice bouncy feel to the ride.

 it looks like this after 15km 10 tarmac / 5 offroad

Does anyone has an idea what can cause this problem? I did not crashed withe the bike, once, and in the summer there was not a single drop of oil on the stanchion, even after 2500km of offroad. :((

This is how it looks after 30km :(

Hope you can help me. (Please do not suggest to got to the local bike shops, they don't work with fox shocks)

I am certainly no expert in shocks, only ever stripped one model a couple of times...

Is the shock holding pressure?  If so, its the wiper seals leaking not the aircan seal - check the damper body for scratches/damage. If not external damage I would re-service the shock pay special attention to the damper body condition and that the damper seals were correctly reassembled.

If the shock is loosing pressure, it will be the aircan seals. Check the internal surface of the aircan for scratches.


How can I determine the model year of my GT Talera bike? How can I determine the model year of my GT Talera bike? The serial number starts out as CM17F5

Assuming you own it, try registering the bike on the GT website at http://www.gtbicycles.com/can_en/bike-registration
You'll need to provide contact info of course.


Chain not running straight at the front I have a touring bike which works fine. But when I shift to either of the two larger cogs on the front the chain hits the derailleur on both sides. Obviously it's because the cogs don't run straight but I'm unsure what my best options are. (It moves around on the smallest cog as well, but not enough to hit the derailleur)

Can I bang this around judiciously with a hammer and fix it, or is it something that is a potential danger and needs service, or should I just take the derailleur off?

If I take the derailleur off then I'll just have one front gear, but I could probably live with that. There's no bike service places in this country, nor do I have special tools.

Bending the chainrings back is a possibility, but what you want to avoid doing is bending them around when what's actually causing the problem is misalignment coming from either the crank or BB spindle.

If the warble on the rings is uniform across the three rings, that's a strong but not automatic indication of a bent or poorly aligned BB spindle.

If it's the larger two only but the inner is more or less straight, that's a strong indication that the crank spider tabs are misaligned, which is often a fixable problem. Spider tabs can be "trued" by removing the chainrings, taping something flat like a popsicle stick to the FD to use as a gauge, and bending them around using an adjustable wrench so they run true with each other. This is bending aluminum, which always introduces some risk of fatigue failure. Then put it back together and if that doesn't work, you can try working the individual spots on the rings back into alignment.

Just making it a one-by may be reasonable, but it can be difficult to get it to not drop the chain if you're not using anything to help keep it on. Good chainline is a must if you're going to avoid this, but it's not necessarily enough.


England Fix Your Bike Voucher Scheme: how not to miss the next release? The UK government is running a Fix Your Bike Voucher Scheme in England which allows members of the public to receive a voucher worth up to £50 towards the cost of repairing a bicycle.
At the time of posting, the voucher scheme has been hugely popular and all vouchers in the first and second releases have now been allocated. - this is two days after the second release.
What can I do to make sure I don't miss the next release?
The scheme has this FAQ page which also includes a question to the same effect, and what does it do with it? Of course it dodges it! Come on, it's the government, what did you expect.
Note: I know this scheme opens several ethical questions: Should I apply or leave it for those more in need? Why doesn't the government allow notifications, or a waiting list, or a prove-your-need bidding system? This question is not the place to discuss any of this.
I can think of the following example answers:

A link to a website or forum where you can sign up to get notified,
A way of "sensing" a release approaching - perhaps someone with an understanding of government and book-keeping mechanisms knows that it can only be on a Thursday?

As a secondary question, why does it seem nobody has ever asked this question on any forum? I thought everyone would want to know? Is my question illegal or against the (undefined) spirit of the scheme?
Also, I have reservations about the wording of the Title of my question, especially the use of a negative "how not to". If you can improve it, go for it, and remove this line from the Body too.
Finally, I am conscious if this question is fit for this SE, but people seem to have got away with some much worse questions.

The 'fix your bike scheme' forms part of the UK Conservative government's range of economic populist measures in response to covid-19 (which included 'eat out to help out', a scheme which gave discounts for restaurant meals to support the restaurant industry, but may have led to more covid cases https://www.theguardian.com/business/2020/oct/30/treasury-rejects-theory-eat-out-to-help-out-caused-rise-in-covid).
Essentially the thinking was 'people will avoid public transport and we should encourage more cycling'. This may relate also to Boris Johnson, the Prime Minister, getting covid-19, and feeling that his obesity was a factor in the severity of his illness (https://www.washingtonpost.com/world/europe/boris-johnson-obesity-coronavirus/2020/07/27/d5d0221c-cff0-11ea-826b-cc394d824e35_story.html)
Other measures have included 'pop-up cycle lanes' https://www.bbc.com/news/uk-53105020 but many have been removed following complaints from motorists (https://www.worthingherald.co.uk/news/politics/pop-covid-cycle-lanes-chichester-removed-no-longer-needed-could-worthings-be-next-3014037  https://you.38degrees.org.uk/petitions/remove-the-pop-up-covid-19-cycle-lanes)
The 'fix your bike' scheme is an appealing idea as there are probably a few million bikes around in bad condition that could be put back on the road but probably they aren't going to that.
Anyway, because 500,000 bikes (the total number of vouchers) is a lot to repair all at once, they are releasing them in batches of 50,000. Only around 4.5 million people in England ride bikes at least weekly

so those vouchers all at once would be overwhelming given the normal volume of work for bike shops/mechanics
There have been two releases so far:
https://www.cyclingnews.com/news/bike-repair-vouchers-launch-in-england/

28 July 2020 at 23:45
16 November 2020 around noon (not announced in advance)

The long gap between the first two releases was due to the overwhelming demand for bikes globally due to covid-19, and massive demand for paid work, so adding more 'free' work into the system had no benefit to mechanics/bike shops at the top, since they had more work than they could perform.
Now that it is dark and cold in England, the bike industry, including repair, has calmed down massively, and government-funded repairs are more welcome.
However with several million cyclists, 50,000 vouchers will not go far.
Since the vouchers are 'free money', the government does not seem to be pre-announcing them, since they demand will vastly overwhelm supply.
I had a look on Twitter, and found:

https://twitter.com/transportgovuk/status/1328316455037919240 12:38pm GMT 16 November 2020

It was also mentioned slightly earlier by Grant Shapps, Minister for Transport (12:31pm) https://twitter.com/grantshapps/status/1328314766121644032, and Cycling Industry News (12:06pm) https://twitter.com/cyclingindustry/status/1328308340292792320
This page should be updated with the new details:
https://www.gov.uk/guidance/fix-your-bike-voucher-scheme-apply-for-a-voucher
A service such as this one, could keep track https://visualping.io/
The vouchers ran out by 9pm and there were also website problems https://twitter.com/transportgovuk/status/1328445587432337410
Given that there are 390,000 vouchers remaining, so 7 or 8 more releases, then you have some chance of getting them if you are subscribed to places that will notify you when the vouchers come out. Tracking the gov.uk page and also maybe https://fixyourbikevoucherscheme.est.org.uk/ for changes might give you a head start, as the pages will obviously be 'live' for some minutes before it is publicly announced. If you wait till the public announcement it's possible that the server will be overwhelmed....
I would note once you have the voucher to shop around carefully, as a lot of repair places will still charge you £££ even with the voucher. They don't expire till March. It is 'real money', albeit possibly paid slowly by the government, so don't be fobbed off with any place that wants to treat it like some kind of dodgy discount voucher - this is paid for by £50 (plus admin!) of taxpayers' cash, it's not like a groupon or something where there is a fat commission to a third party. Obviously though busy repair shops might still prefer upfront cash, hence shopping around....
Note also that the money is for repairs which must include some element of labour, can include parts, but not accessories. Those who are handy with a spanner looking to get some value out of the voucher might find that something like a new tyre (but only if the existing one has perished), chain or cassette would maximise the value of the 'parts' rather than the 'labour', but this is something to be discussed with the shop after you have obtained the voucher

Eligible Repairs include repairing or replacing:
o tyres, tubes, wheels and related components;
o braking system components;
o transmission system components;
o components for permanently fitted lighting systems.
o other essential components which prevent safe use of the cycle e.g.
deteriorated grips or saddle;
• The following are not Eligible Repairs:
o a sale of replacement parts without any repair work.
o replacement or upgrade of existing safe and roadworthy components
or of removeable lighting accessories.


Front wheel wobble at high speeds I've noticed that when I get going above around 30 mph, normally on a downhill, my front wheel starts to oscillate back and forth slightly, like it is steering is a slightly sinusoidal path rather than in a straight line. I'm curious what might be causing this phenomena? Perhaps it is an artifact of my particular body size and frame geometry, or of the wide tire size catching wind (37 cm)? my wheel is fairly true left-right wise although it has a tiny bump in it up-down wise. I'd expect if this were the cause I'd notice it at lower speeds to though. Any thoughts?

You're likely experiencing speed wobble/death wobble:

Wobble, shimmy, tank-slapper, speed wobble, and even death wobble are all words and phrases used to describe a quick (4–10 Hz) oscillation of primarily just the steerable wheel(s) of a vehicle. Initially, the rest of the vehicle remains mostly unaffected, until translated into a vehicle yaw oscillation of increasing amplitude producing loss of control. Vehicles that can experience this oscillation include motorcycles and bicycles, skateboards...
...
In two-wheeled vehicles
Wobble or shimmy begins when some otherwise minor irregularity accelerates the wheel to one side. The irregularity may be a wheel which is out-of-round, out-of-true, or out-of-balance. As the wheel rotates, it will exert a cyclic load to the vehicle frame, which if matched with the system's (vehicle and attached accessories) resonant frequency, can produce a speed wobble. During the wheel rotation, a restoring force is applied in phase with the progress of the irregularity, and the wheel turns to the other side where the process is repeated. If there is insufficient damping in the steering the oscillation will increase until system failure. The oscillation frequency can be changed by changing the forward speed, making the bike stiffer or lighter, or increasing the stiffness of the steering, of which the rider is a main component. While wobble or shimmy can be easily remedied by adjusting speed, position, or grip on the handlebar, it can be fatal if left uncontrolled.
...
An academic paper that investigated wobble through physical experimentation and computer modeling concludes: "the influence on wobble mode of front tire characteristics, front frame inertia and chassis stiffness were shown. In particular, it shows that [by] increasing front tire inflation, chassis stiffness, and front frame inertia about steering axis and decreasing sideslip stiffness of front tire, wobble mode damping is improved, promoting vehicle stability."

So this can (and does...) happen with just about any bicycle.  And as the term "death wobble" implies, it can be really dangerous.
When it happens, do not panic. You need to change the resonant frequency to get the oscillations to stop. One of the worst things you can do is grab your handlebars tighter and try to outmuscle the oscillations - grabbing the bars tightly isn't going to "increase the stiffness of the steering" because your upper body is up in the air, attached to the bars by two flexible arms.  So you're really not adding any stiffness to the steering if you grab grab your bars harder.  Not only that, if gripping the bar tighter doesn't work (and it probably won't...), more powerful oscillations will be transmitted through your tighter grip to you and your mass will be quickly added to the oscillations and you'll almost certainly crash.
Relax your grip on your handlebars, and to really change the resonant frequency of your bicycle, clamp your knees against the top bar.
The relatively low pressure of a 37 tire might be a contributing factor.


29" wheels - what advantage do they provide over smaller wheels? I was wondering what advantages 29" wheels give. From what I understand they are well suited to mountain biking. Are they any use on road bikes perhaps?

Regarding road bikes, the 29" rim size is actually the same as standard 700c wheels used on road bikes -- only the tire is different (larger).

One difference that I don't see mentioned often is that 29" vs 26" wheels change your effective gearing.  If you have two bikes with the same gearing but one with 29" wheels and one with 26", the larger wheel will have a higher gearing overall because of the larger wheel diameter (one turn of the pedals move you farther down the trail).  This means that the 29er can help you reach a higher top speed, but the 26er will have a lower climbing gear.

Also see the comparison on Wikipedia.


Help identifying brand of bicycle I'm attempting to identify the brand of bicycle that is shown in this picture.  Unfortunately these are the best quality I can find.  When I zoom in the letters are too grainy to see.

Can't tell.  The threaded stem, cheap looking fork, along with the warning sticker on the crank not to thread the wrong side pedals in the wrong crank arm, along with the plastic chainguard on the crank, all point to it being a department store bike.


Are you required to cross the finish line on a bike? Suppose you get a flat 100m-1km (or some distance that you can sprint/run) from the finish line. Can you leave your bike and run the remaining distance to the finish line? Or are you required to carry your bike while running? Or are you required to cycle across the finish line (i.e. wait for a service car to come fix your bike)?

UCI regulation 1.2.109:

  The rider may cross the finish line on foot, provided that has his bicycle with him.

Note that "his bicycle" may be a teammate's bike or a neutral service bike (and that "he" may be of any gender but the UCI are too lazy to rewrite their rules).


Need help in identifying bike I have got a bike as a birthday present. But I can not find it on the official website. So can you help me identify the bike please? I wonder if it is the original Bulls bike or replica. Also wonder which model it is. Thanks in advance

Based on their website - they don't sell fatbikes.  The two models of full-squish bike are called "wild cup" and "wild one"
https://www.bullsbikesusa.com/wild-cup.html

But the images show "normal" sized tyres, and distinctively different top-mount for the shock.
So either its a model no-longer sold, it's from a different company with a similar name, or it is a knock-off.
Ask the giver for the paperwork so you can "register the warranty" and do enjoy your new bike.


Is it appropriate to carry furniture with bike and suggestion for equipment I am coming from a culture where there are not many bike roads.
But now I am moving to a place where bike roads are awesome and cool.

Since I do not know the "bike culture" well in Denmark while I think this should be acceptable  I wanted to ask if I try something like below,

Is it legally or culturally bad . BTW While looking for stuff I am trying find ones close to my house which is far from center to avoid dense population and narrow bike roads.

If it is OK do you have any advise for a trailer type or other equipment(for example like green and orange ropes in the picture) to accomplish that?

Based on the photos on the Christiana website I think you'll be fine. The exact law I'm not sure of, I can't find a translation of their bike laws online.

It seems that people do carry big loads on bikes there, which isn't surprising given the strength of their cycling culture. You have the right idea about not doing it in rush hour.

The generic load carrying questions are easier to answer. I suggest not loading with the centre of gravity as high as your photo because it means you can't ride on roads where there's a side slope, and cornering is harder. But if that's the trailer you have, that's the trailer you'll use. Just be careful.

I would build or modify a trailer that's as wide as I can get down the paths in the area, once you have somewhere to live. I have built trailers more than a metre wide and not had problems, and in both cases I have built them so I can have a flat platform over the wheels, which lets me have loads wider than the trailer easily.

(big) (big)

(same trailer, flipped upside down to use a second set of dropouts. Or just load it so you can have a higher layer of stuff that sticks out more)


How can I add full fenders to a frame with no braze-ons? I recently picked up a bike I want to ride in Seattle rain, but missed the fact that the frame had no braze-ons for attaching full-coverage fenders. I already have a set of SKS Raceblades, but they only provide partial coverage. Do any manufacturers make full-coverage fenders I could use?

Crud Roadracer Mk2s offer a bit more coverage than raceblades I believe

http://www.crudproducts.com/products/roadracer/roadracer_


What is the recommended tension for my AlexRims X2100 rim? I'm working on a bike which needs a couple of fixes, but the truing process is a new world for me. And I want to give long life for the wheel.

I have a 26" wheel with 32 plain gauge spokes (aluminum steel). And it needs some truing but I want to know the right spoke tension. After I went over a few videos I figured out that the easy way for me would be using an app such as CheckSpoke. You set the spoke length and diameter and then pluck the spoke and it shows a reading in Hz and N.

What should the readings shows for good tension on DS and NDS?

I'm truing a rear wheel with a cassette.

Some manufacturers have published recommended spoke tensions for their rims. For two examples, Mavic recommends 70 to 90 kg (700 to 900 N) in front and drive side rear and Velocity claims 110 to 130 kg (1100 to 1300 N). Non-drive side tension should be set so that drive side is at recommended tension and the rim is centered.

For high spoke count road wheels there is a workaround where you increase the tension until the wheel turns slightly taco shaped and then back off until it is true. This works for narrow rings like Open Pro, but can result in excessive tension for smaller and stiffer MTB rims.


Shimano PD-6800 vs PD-9000 pedals Other than a 12g saving in weight and the Dura Ace label, are there any further potential reasons to prefer Shimano PD-9000 pedals over PD-6800?

Edit: This question is specifically about pedals rather than general Dura Ace vs Ultegra comparison.

In addition to the points noted in other answers, there is a significant technical difference: bearings.  Traditionally, Dura-Ace equipment with bearings has had much better quality bearings/races/cups/seals/etc. That appears to be true here as well. Look at the parts breakdown documents from shimano and you'll see a significant difference in the axle/bearing setup:

PD-6800 - 12 ball bearings inboard, 12 outboard with bushing between
PD-9000 - 17 ball bearings inboard, 9 outboard with needle bearing between

The bearings in the 9000 will live much longer and deal with intense loads better than the 6800. That said, the 6800 is a fine pedal.


Bug Repellent for Mountain Biking that won't melt my gear? The east coast is supposed to have a really bad year for ticks with Lyme disease as well as the concern about Zika Virus and West Nile Virus.

I know DEET is effective at both keeping bugs off and melting technical gear. I'm worried that repeated use of DEET will destroy my nice Goretex jacket, my expensive bib shorts, my softshell trousers, synthetic jerseys, and technical overshorts.

What's the best option for repelling mosquitoes and ticks for mountain bikers riding in the woods that won't harm my technical gear?

See Example:
http://sectionhiker.com/deet-dissolves-breathable-fabrics-experimental-results/
https://www.outdoors.org/articles/amc-outdoors/two-common-hiking-items-that-deet-will/

Check if icaridin (Wikipedia) protects against disease vectors in the region you would like to bike at.

Icaridin is less damaging to synthetic materials, less sticky, and repels many types of insects (and arthropods).

Icaridin also has down sides, for example, it may not be adequate for some disease vectors and a single application does not protect as long as DEET does.

Please note, that these draw-backs are particular relevant for 7% solution of icaridin. Most comparative tests that find an equivalent effectiveness of Icaridin to DEET use a 20% solution. The latter may not be available as a commercial product in your country.

The topic effectiveness of insect repellents is also covered on (travel) stack exchange.


Negative 17 80mm stem on MTB? I currently have a 27.5 hardtail mtb. I use it for commutes and traveling rather than trails or downhill tracks. I'm planning on upgrading some parts and one of them is the stem.
Will a -17° stem have some benefits or help and improve my riding? Given that I only ride on roads and use my bike for commutes? What can I gain from using a negative stem?

Lowering the hand position will essentially move your shoulders forward and down, in an arc.  This will put your head further forward, and you'll have to look up slightly more.  It will also put more weight on your hands.
If you currently ride with your elbows slightly bent, then they will end up straighter.
This will also very slightly rotate your pelvis forward too.
I'd suggest confirming your saddle height is good first - assuming you're riding on the road, then it should be high as possible but not enough to make your hips rock side to side.  If that happens, lower it by a few mm.
Also if you're riding on road only, you don't need the wider handlebars.  Narrower bars let you fit through traffic gaps better, and will be slightly more aero.


Is it possible to fit this Tioga Mc Groove saddle on my bicycle? See images here.

The bar the new Tioga saddle is mounted on is a bit thicker than the one the original (terrible) saddle is mounted on and won't fit as is.
I can take the old saddle off its bar no problem but it seems like the new saddle's bar can't be removed without removing the clamp.  The nut with a slot for an Allen key (it's actually not, it's slightly bigger than a certain Allen key size) is unbelievably solid; it will not budge, which leads me to believe it's not intended to be opened.
I took out the metal bottom inside of the plastic bar with an Allen key.  Insides there's a removable spring and deep inside (inside the plastic) it looks like there's another thing to be opened with an Allen key but it's hard to tell.  Even if it was, I don't know what kind of tool is able to open something like that down a shaft.
I tried a lot of other pointless things, including heating up an Allen key so it would expand enough to fit properly; I'm pretty desperate at this stage.

Do saddles vary for different size slots (i.e. different bikes)?
Is it possible at all to fit this saddle?  If so, how can it be done?

Yes, your bike can be fitted with pretty much any saddle.

The (metric) allen key on your new saddle is a 6mm. If you're using Standard Allen wrenches its probably a little larger than 7/32".

The seat post needs to fit your frame. So you will need to mount the new saddle on your old post, or buy a new post that exactly matches the size from your original one.

It does sound like you've disassembled the guts of your suspension seat post, so if you can't get it back together, you're probably looking at a new seat post.

There should be no problem mounting that seat on any post that fits your frame.

I hope that helps.


taking bike on vacation I'm planning to take my bike on this year vacation but I have certain dilemmas where and how to keep bike secure during my stay. Bike is nothing fancy (MTB, 26" wheels, full suspension bike with Manitou shocks, aluminum frame, new SLX groupset, Fox DOSS seat post...) more of a sentimental value because I put too much work and effort in maintaing it.

First of all, I'm staying at a hotel which doesn't have secure room for storing bikes and management doesn't allow keeping bikes in room or on balcony. Hotel only has bike racks at the entrance to each hotel wing (some of theme are covered with 'security' cameras) and most guest keep their bikes locked there. At night, those racks are in dark and I have no idea if I'll be able to see it from my room.

My concern is that by keeping my bike with other bikes (usually cheaper ones), it will stick out and be nice 'target' due to higher end parts and components.

The other option is to keep bike inside my car on unsecured parking lot (no street light, no surveillance) which is even further away from hotel and my car has no alarm to hear if someone tries to open it.

My bike will be unattended during night, and most of the day while not riding it (meals, going on beach...) I also considered leaving my bike at home and renting bike but prices are outrageous - so it isn't an option.

To be honest, at the moment I'm still searching for a decent bike lock so I have yet to solve that part of a problem (and I'm probably little paranoid when it comes to bikes).

Any ideas and suggestions how to secure bike (and enjoy vacation) are more than welcome.

You could try leaving the bike in your car, but covered with a dark blanket so that its not visible at night, it would be even better concealed if you took the wheels with you into your room at night as it could make the blankets profile flatter (handlebars turned to be inline with the frame).

If you dont mind taking it apart even more (pedals and wheels) you could even get a bike box to put it in, when you cover it with a dark covering then it would present a flat surface in your car which would be almost invisible in the dark.

Additionally, park near a street light or as close to the entrance as possible so its covered by the "security cameras" you mentioned.


How many spokes can break before I need a new wheel? 3 of the spokes on my wheel are broken. How can I tell if the wheel is still good to use?

Can I just replace the spokes or do I need to buy a brand new wheel?

The spokes support the wheel under compressive load. The rim in itself is relatively weak in compression. Of course, losing a spoke means that the remaining spokes have to carry increased load and you risk breaking more spokes or buckling the rim beyond repair.

(Note: minor buckles can be removed through "truing" the wheel, a process of adjusting spoke tension to pull the rim in both the axial and radial directions so it is round and straight again)

Recommendation:

Have a bike shop assess whether the rim has been damaged from riding on 3 less spokes. If they deem it is still usable, then they can replace your spokes (possible more than just the 3 which broke) and true the wheel if necessary.

Further reading:

There are some interesting websites that consider analysis of a spoked wheel:

Spoked wheel analysis

Bicycle wheel stiffness


How to install a Rohloff Speedhub on a Surly Troll with rear facing horizontal fork ends I have a Surly Troll with rear facing horizontal fork ends.

Is there a recommended way of installing a Rohloff Speedhub 14 on the Surly Troll? These answers mention tugnuts and washers, but perhaps Rohloff have their own adapter for this type of bicycle / fork end.
Or perhaps the Surly Troll with these fork ends wasn't made for an IGH?

Pictures of the fork ends (this is a pre 2017 Surly Troll):

This is the answer I received from Rohloff customer support

https://www.rohloff.de/en/service/search/bike-finder/details/item/troll/

  Built of 4130 CroMoly steel, the Troll is designed as a comfortable off-road MTB/tourer. The frame feature gusseted sloping toptubes, Surly Trip Guides for running full shift and brake housing, mounts for linear-pull and disc brakes plus ample room between the stays for high-volume rubber…up to 2.75"!

  The Troll’s…rear load horizontals feature a derailleur hanger, slotted disc brake mounts, M10 x 1mm threaded holes for mounting the Surly Bill & Ted trailer via connecting hardware (or B.O.B. Nutz), and a dedicated anchoring point for a Rohloff OEM2 axleplate. Surly designed a ton of versatility into these framesets because they wanted you to build a bike the way it will best serve you. Framesets available in sizes XS, S, M, L and XL.

  The Troll, requires:

  Disc brake use:

  TS DB OEM2 SPEEDHUB + special 4-bolt brake rotor + spokes with a 2.9mm neck length.

  Rim Brake use:

  TS EX OEM2 SPEEDHUB + spokes with a 2.9mm neck length.

  The OEM2 anchoring bolt is positioned in the additional horizontal dropout slot as illustrated above.

  PLEASE NOTE:

  2017+ Troll models will in addition, require the Surly '10/12 washers' to convert their 145mm 'Not-Boost' dropout system back to 135x10mm standard.

And this is the answer from Surly customer support

  ... Troll’s rear dropout actually features a dedicated Rohloff torque arm slot. Our recommended set up is the OEM2 axle plate and the a Speedhub that uses the “TS” (bolt-on) axle paired with our 10/12mm adapters (below) to allow the axle to sit snugly in the Troll’s 12mm Gnot Boost dropout.  You can also get one of our Snuggnuts if you are concerned about the wheel slipping, but most of the time, the bolt on axle is sufficient.


Getting a dura ace 7800 derailleur to work with 10 speeds I have a bike set up with a dura ace 7800 derailleur, specifically listed as a 9 or 10 speed model. I am interested in getting it working in the 10-speed configuration. Two things:

I remember reading somewhere that you have to rout the cable a certain way to get it to work with 10 speeds, but I can't remember how to do so.
I can't get it to rest in the bottom gear even when the limit screw is all the way out and the cable isn't attached. I can easily force it into place, though. I am considering taking out a spacer from behind my cassette that the instructions said I would be needing.

Any advice?

The Dura Ace 7800 rear derailleur has two different positions for the pinch bolt/clamp that holds the cable in place.  One of these positions will limit the derailleur's range, and make it incompatible with 10 speed systems.

If you loosen the bolt, re-orient the clamp, and tighten again, it should work on your 10 speed system without any problems.


What features make a good fitness tracker for cyclists? What features are needed, and what ones are desirable on a fitness tracker for a cyclist? I am looking for one that will support jogging, walking and other exercise, but cycling is essential.

There are heaps of 'reviews' of these things, and a such large number of products available, I can't find information that gives me much confidence that any particular model supports cycling, and how well it does.

How can I assess what is a good fitness tracker for someone who primarily cycles, but not exclusively.

More constraints, this is for a small woman who can't wear a chest strap or watch/band (5ft with really thin wrists). She also runs(slowly), users a scooter(leg power/not motorised), walks and plays soccer occasionally.

She wants to get an accurate measure of energy use in kcal - and the tracker we tried was not very accurate.

Willing to look at multiple devices, if that is the way forward.

I come to this question as (in chronological order) a speed skater, cyclist, and runner. I have been a full-time Data Whore since early 2007. I have used various Garmin devices and smartphones. What I have found works best is the device that is on your person, with a sufficiently charged battery, and actually recording data.

I spent five years using a Garmin Forerunner 205 on a daily basis. That thing rocks, but Garmin’s device firmware that provides the user interface is just universally terrible. In spite of that, they are still very good devices for their intended purpose. After swearing I’d never buy another Garmin I was given a 405CX and after giving that away a few months later, was given a Forerunner 305. I still use that to this day.

Smartphones are great for “light” use, but when the GPS radio is running full-time, as required for an accurate athletic recording, battery life will absolutely be an issue. If the total riding time in a day will never exceed a couple hours, a smartphone could work. If devices such as heart rate monitors, cadence sensors, etc., are desired, they can be used with various smartphones by way of either ANT+ adapters or using Bluetooth accessories.

I’ve also long had issues with chest strap HRMs, in that they simply don’t stay up when I run. If I tighten the strap enough to keep it in place, it makes me nauseous. But recently I have realized that putting the sensor on the left side of the ribcage just below the armpit still gives a good read and stays in place better, and that even letting the whole thing slide down so that the sensor is over the solar plexus still seems to work. And I’m a relatively thick-chested male; conventional wisdom is that smaller females tend to have an easier time getting a read because there is less tissue to attenuate the electrical impulses.

Now, all that said… I say spring for a standalone GPS device if possible. They will offer significantly better battery life, and at least as of late 2014, still use much better radio hardware which makes for more accurate and less glitchy data. Many of them can be quick-release mounted on either handlebars or a wrist strap. But if you do go with a phone positioning accuracy will be close enough, and without a whole lot of biometric data (not just heart rate but also oxygen usage), caloric expenditure is just a wild guess anyway.


Looking for a new bike, any tips for buying a good bike? So as the winter is coming and I have never ridden with a bicycle to work in winter I need a bike that can be fast, but at the same time safe for winter. I have heard that there are some winter tires for bikes, do they really work?  Any tips on those too?

Probably some of you are commuting to work with the bike a long time now and I hope I can get some good tips on that.
To be honest, I have never ridden a bike to work, so any kind of tips will be appreciated.

You don't say where you are located, so it is bit hard to tell what your specific requirements might be, but you do make a distinction around 'winter riding'.  So let's assume you mean cold, perhaps treated roads, perhaps snow, perhaps ice.

For tires, while there's some tension between 'wide' and 'fast', I would suggest 32mm or wider, if they'll fit in your frame, fork, and brakes.  Something with tread if you plan on riding in the wet or on treated (gravel-covered) roads.  If you expect to encounter ice, you may want studs.

Another unknown is time of day and what the lighting conditions will be.  In my opinion the single biggest safety improvement you can make is to ensure you are visible in darkness and in low light, to drivers who are in a hurry, tired, and often distracted.

I would recommend highly visible (hi-viz yellow and orange) clothing, many reflectors (especially moving reflectors, such as ankle bands and spoke reflectors), a bright, multi-mode, rechargeable stroboscopic rear light; a bright, constant-beam, rechargeable front light, and an auxiliary stroboscopic white front light.  There are many good choices out there.

There are also helmets with integrated safety lights available; these work well in my experience.

If you are looking for specific product recommendations I'm sure many folks can provide them.


Convert 2019 Giant TCX Advanced Pro 2 1x to 2x I'm looking at a 2019 Giant TCX Advanced Pro 2 which was sold as a 1x.  I have a Shimano 2x groupset laying around and would love this bike as a 2x.
Based on this image from this sold listing, it looks like there's a spare entry into the downtube:

And this review shows a hole behind the seat tube above the BB:

Are my eyes decieving me or could I run gear cable down that and into a front derailleur?

Response finally came through from Giant:

Yes, you should be able to route cable for a front derailleur.


What is the theory behind a gravel bike? As I understand a gravel bike, it's basically a road frame but perhaps with a slightly more upright riding position. It has wider tires with much deeper treads and a stiffer rubber than standard road bike tires. What is the theory behind these changes? I had always thought that the thicker and stiffer tires were to prevent small bits of gravel from pinching flats, but is the theory instead that the deeper treads and wider tires are supposed to increase traction? And what is the rationale for the upright riding position?

GCN had a funny take on this recently: Gravel bikes exist because mountain biking is now boring. Or to give slightly more nuance, mountain bikes make it so easy to ride over difficult terrain that they remove the challenge.
Coming at it from the opposite direction, road cycling may be losing some popularity because A) roads in many places are poorly maintained due to austere public-works budgets, and B) motorists are motorists. Which creates some demand for something that you can ride on bad roads/roads that motorists don't drive on.
Gravel bikes generally are designed for a little more comfort and stability than a road-racing bike--more in line with a road "endurance" bike. Hence the more upright position and slacker angles. Some people ride gravel bikes with fat slicks—I don't think you can make any sweeping judgments about tires, other than they're fatter than road tires.


Reassembling rear wheel hub I have a ten year old decathlon cheapo bike and I wanted to take out the axle out of the rear wheel to see if I could replace it with a quick release mechanism and also learn a bit about how it works (the bike is cheap and not important). I undid a few nuts until I could take out the large axle bolt but when I did, out fell a load of ball bearings from either side.

I don't think I'll be able to reassemble it and a lot of the parts are rusty and probably need replacing but I don't know what to replace them with and like I said, ideally it would be quick release.

As far as I can tell the assembly is a freewheel cassette. Then there was this large bolt going through the wheel with two nuts and another threaded item I cant identify either side. Inside there were the bearings each side with a washer like cover. But they seemed only to be held in place by the presence of the bolt.

Edit: The bike is a rockrider 5.0 from about 2010 or so.

Yes, that bolt was the closing side of the ball bearings, your current axle is probably a "cup and cone" hub.

You opened the cup, so the ball bearings that where rolling on the cone just fell off.

You have to replace them (same diameters and possibly same hardenss ...), clean and grease all the parts (rusty and not rusty, it does not really matter).

Finally, you can replace the axle with a quick release skewers, but it must be of the same (internal) length as the one you are replacing (130mm, probably).

Giving the exact bike model or at minimum a picture of the wheel&hub may help us help you.


How accurate is Google Earth I always use Google Earth to plan my cross-county routes. Lately, I have begun to ride long distance trips (over 70 kms). Checking my bike computer against Google Earth I have noticed consistent discrepencies of over 10% (computer give me more distance than Google Earth).

I have checked my computer againts my hand held GPS (old Garmin eTrex) and both differ by less than 0.5% in short test (2.5 kms). Also, I cross checked with my ride partner and we both are getting the same readings (+/- 3%) from our computers (different brands) over long distances (20-30 kms).

My bike computer is generic cheap chinese model. I can only select whole wheels size (26"), with no fine tunning. I trace my routes over dirt/paved road, so I certainly keep my planned course.

Can you explain why real distances (according to my computer) are always +10% over Google Earth? What's your experience?

It largerly depends on how you are marking the route in Google Earth and how you actually ride it. There are a couple of factors that introduce small diferencies when measuring distances and their effects are multiplied over distance, so the longer the route, the bigger the difference.

The straight line effect

For example, if I plan my route drawing a line over the map, but I only mark some points, Google will draw a straight line between two consecutive points. Remember that the shortest path between two points is a stright line, any other path will be longer. But when you actually ride the route you hardly ride straight lines, you ride curves. Each curve will add a little more than each line segment in your map, so, when adding all these diferencies up, the result is a longer actual ride than the planned line.

When following or marking a route using some sort of GPS based solution, you have to account also for the "sampling frequency" of the device. For example, lets say you take a minute to travel around a roundabout. If your GPS device also "samples" your position every minute, it will likely mark your position twice in the same spot, so it will record 0 traled distance. This will affect you more in the more curvy trails and routes, specially if you ride at higher speeds. GPS based solutions also work calculating the distance from two consecutive points and adding up with the next pair, and so on. (Yes, it asumes a straight line between points). The higher the sampling fequency the more acurate the distance will be recorded, but also battery consumption will be higher and if files are a concern, they will also be bigger.

This also occurs in the vertical dimension. For example if you side over a small hill first going up a few meters, then going down over an otherwise straight path, but you marked only the beginning and ending point, most likely the software wont take the hill into account, measuring the distance as the straight line between the points.

The curved line effect

There are also another factor that comes into play: We all know that most bike odometers work by counting wheel revolutions. But many of us do not mentally acount for many wheel turns that are not actually accounting for travel distance. Lets say, you lift up the bike and let the wheel spin, or when you get to a resting point and do a few empty loops while waiting for other riders, etc...

Something else is that, in curves, the front wheel actually travels a longer distance than the rear, and you, actually travel a distance that is in between. For example, lets say you ride trhoug a puddle that makes both your tires very wet, an then on a dry surface you ride a really tight U-turn. Now see the path marked by your tires. The fron one must have drawn a bigger semicircle than the rear one. If you want to be sure, measure them with flexible metric tape ;) This seems too little, but over a long route, every tight corner you ride, actually adds up to the distance "seen" from the front tire.

The longer the route, the more this will affect your predicted route distance versus actual ridden distance. But also, the more curvy routes are the ones more severely affected.

To improve the distance acuracy of the planned route, use shorter line segments along curved parts of the trail, i.e. put the points close together.

Note: I have always doubted about wether Google really takes into account ground level when measuring distance over traced paths, I don't know if it includes altitude of the ground at the marked point or if it assumes all points are at the same height. If it asumes same height, calculated line length is less than the actual path.


Spinning bike speed vs outdoor ride speed I have been riding indoor on spin bike and I average 40 km/h, would someone help me translate these speed to outdoor cycling?

Based (very roughly) on this calculator here, I'll guess 28 km/h or less.

Using a 0 weight rider and bike with no wind and 200 watt output you get roughly the speed you are getting on the trainer (the weights are used for rolling resistance).  Leaving the power the same and changing to 80kgs, a 9kg bike and 15 km/h wind it gives 28 km/h which is a significant drop.  I am not sure about all the formulas the calculator is using, but introducing rolling resistance and wind resistance will surely take big chunks out of that speed.

I am not sure what kind of spin cycle you are using, but depending, it may be introducing some sort of resistance that it equates to rolling/wind/mechanical resistances.  However, it's likely much less than what you would encounter out on the road.


Gash where valve meets tire tube; How could this happen, and can I fix it? I'm fairly new to bicycling; apologies if this is a standard question but I couldn't figure out how to phrase it to search for it elsewhere.

I ride a KHS Urban-X with Kenda Kwest tires (just what it came with). I've gotten barely any use out of it since owning it, and it's been resting comfortably in the living room through the winter, so I decided today was a great day to get back on.

So I unscrewed the back tire cap, and began to hand-pump air into the tire. All seemed to go well, and the tire held pressure fine, but when I removed the tire pump, the pin appeared to remain pushed down slightly, and air flowed back out of the tire. I looked, and this is what I saw:

Several narrow gashes that appear as if the rubbed was ripped, cut, or separated somehow.

Questions

Is this a common occurrence? Again, I've ridden on this bike very little and thus filled up the tires even less. We have no animals and no bugs around that I know of that would gnaw or chew on such material.
Is this fixable, or is my tube completely shot? It would seem to me that the latter is the case.
Is there anything I can do to prevent this in the future? I use a hand pump but am gentle; would a stand-up pump be a better choice?
Do bike tires come with a standard warranty for cases like this, or do you know of any brands that do? If I have to purchase new tires, I'm going to purchase
Is there any kind of "off-season" maintenance that I should be performing on my bike that could prevent things like this?

Thanks in advance for any help you can give!

Most likely this is a result of riding the tire while the pressure is too low.  When you do that the tube tends to slide around in the tire and can get cut against the edge of the rim.

However, this could also be the result of using a hand pump, which, if you don't "buck" it against something or hold the head steady will move the stem back and forth rather violently.  A "floor pump" prevents this sort of damage (and also makes inflation much easier).

The tube is toast.  However, this is not a particularly expensive repair.  A new tube will run you $5-10, and replacing it is something you need to learn to do anyway.


Determining which derailleur hanger is compatible with a frame When your derailleur hanger needs replacing, is there a good resource for matching frames to hangers?

Mine was recently bent, so I had to dig through some websites and compare pictures of the hangers to my bent unit. Surely there's a better way. Any ideas?

Wheels Manufacturing has a feature to search by brand for their hangers. Just one company of many that produces replacement hangers.

http://wheelsmfg.com/products/derailleur-hangers.html