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65 votes
Accepted

How is this damaged aluminium frame likely to fail?

How is this damaged aluminium frame likely to fail? Sorry. It's not going to fail, it has failed. It's no longer ridable. The head tube is near vertical making the steering very unstable and the ...
40 votes

What is a taco?

To taco a wheel means you've bent it so badly its a write-off and cannot be salvaged through truing. This is significantly worse than going out of true, because the rim will be creased or torn, ...
  • 106k
38 votes
Accepted

How bad is switching derailleur gears under load?

The answer heavily depends on the groupset construction/generation and personal perception of what is "bad", among other factors. Below are a few aspects that I am aware of. Switching gears ...
35 votes

Does riding high gear up a hill damage a recumbent bike?

The bike will be fine -- the riding conditions are within the specifications of the bike components. The bigger issue is you -- you don't want to end up damaging joints and what not by overexerting ...
  • 45.7k
35 votes

Warranty on lock damaged during attempted theft

Warranties exist to protect you, the consumer, against defects in materials or workmanship, not against deliberate damage. The purpose of a bike lock is to help avoid your bike being stolen, so if it ...
  • 12.2k
30 votes

Big dent on frame: How did this damage happen?

It seems that this dent belongs in the bike. Here is a photo of a similar bike. While image is of low quality, the dent is visible: However, as pointed out by Lamar Latrell in comments, in your ...
  • 1,397
25 votes

Is it safe to ride an aluminium bike with a big top tube dent?

My opinion, which is very much my own, is that this is safe to ride home and may provide some level of “emergency use” where no other bike is available and you need to get around for a short while, ...
  • 12k
24 votes

How does a bike 'degrade' whilst unused

Of course things rust in normal use. Still, rust without moving is worse, as things stick together. Even if the chain is generously oiled (more so than normal) before storage you'll get rust and ...
  • 48.9k
24 votes
Accepted

Did my frame just break?

I think its just the hanger that has broken. They're not cheap, but they cost less than a new frame. Keep the old bits and reassemble them, and then compare with https://wheelsmfg.com/derailleur-...
  • 106k
21 votes

Does riding high gear up a hill damage a recumbent bike?

A very strong rider will put a lot of strain on the bike doing that. Wear on the sprockets will be slightly increased by grinding a small sprocket, but that's not a big deal. What's more significant ...
  • 48.9k
21 votes

Big dent on frame: How did this damage happen?

If it is damage then no one here can say for sure how it happened. However, it's in the realm of impossible-ish for a dent that severe to happen without paint damage or a clear mark in the paint ...
20 votes

Is it safe to ride an aluminium bike with a big top tube dent?

I’m not an engineer. With that caveat, I think this frame is likely to fail. It may depend on how thick the tubing is, and if you see little cracks anywhere on the tube, I would stop immediately. ...
  • 22.1k
19 votes

I have a bent aluminum rim on my Merida MTB. Is it damaged beyond repair?

UPDATE That aluminium rim is cracked. You should scrap it immediately. The crack is a weak point and if you try and straighten it, the crack will widen. The air pressure in the tyre will lengthen ...
  • 106k
18 votes

What options do I have if my rear derailleur breaks when I'm out on a trail?

If you carry a multi-tool which happens to include a chain tool, you could also convert your bike to a single speed. If you do so, you would have to replace the chain afterwards as well (since you ...
18 votes

How is this damaged aluminium frame likely to fail?

Oh, that frame is done. It’s not worth saving a few hundred bucks now and spending thousands in the hospital later. Make sure to check over the rest of the bike, especially the fork. It might have ...
  • 12.2k
17 votes

Warranty on lock damaged during attempted theft

Some locks offer "insurance" where you can get a payout if their lock fails to protect your bike. Of course there are caveats like "lock must be used" and "thief must leave lock behind" (for ...
  • 106k
17 votes
Accepted

Why is a damaged bike tyre a problem?

Two things could happen: You pump up the tube, and after a while, the side of the tire yields. Usually when you´re sitting on the bike, because that increases the pressure a bit more. Looks like it ...
  • 305
17 votes

Is it safe to ride an aluminium bike with a big top tube dent?

I would ride that bike as little as possible before replacing it. Being aluminium, it will fail rapidly once the metal tears properly. If it were steel with the same damage, it could still outlast ...
  • 106k
16 votes

Big dent on frame: How did this damage happen?

I think you'll find that the handlebar 'stem' folds to the left, and will line up with the dent when folded. If the dent is not supposed to be there, my best guess is that the handlebar was folded ...
16 votes

What do I do when I am unsure if damaged carbon fiber is safe to use or needs replacing or repairing?

Carbon fiber composites are made up of sheets of carbon fiber filaments. These are usually impregnated with resin. To make CF structures, manufacturers will cut up the sheets, then lay them up onto a ...
  • 22.1k
15 votes

Broken rear brake - told it was unfixable

The brake pivot broke off the frame in a very unusual way. A framebuilder may be able to contrive a pretty cheap way of fixing it by putting a new pivot stud in. This would still require removing the ...
14 votes
Accepted

Frame with bottle cage boss ripped out - how serious is the damage?

You'll need to very carefully inspect the area around the boss that's been ripped out, as well as your usual second hand frame check. If the bike was ridden after the damage cracks could easily have ...
  • 23.1k
14 votes
Accepted

Shredded bits of material under my trainer

Yes, its tyre rubber. People typically use either old/worn, cheap hard compound or dedicated turbo tyres for this reason with wheel on style trainers. The bad news is that more typically sprays off ...
  • 17.4k
14 votes

I have a bent aluminum rim on my Merida MTB. Is it damaged beyond repair?

When dealing with dents like in the first photo only… I get dents like this all the time. I straighten them out with a crescent (adjustable) wrench. Start with small movements to get a feel for how ...
  • 2,567
13 votes

What options do I have if my rear derailleur breaks when I'm out on a trail?

Another suggestion: Scooter it. The bike is functional but the drive train cannot transmit power. So one solution is to scooter along with one foot on the opposite pedal, and your other foot ...
  • 106k
13 votes

Warranty on lock damaged during attempted theft

It still doesn't hurt to contact the manufacturer, but do not talk to as if they owe you anything. Do an open inquiry and see if there's anything they can do. Companies can actually do things out of ...
  • 231
13 votes

How is this damaged aluminium frame likely to fail?

The problem with aluminum is, that it tends to break abruptly. Aluminum can bend under pressure, but it does no stretch significantly under tension before being ripped apart. You get no warning, you ...
13 votes

Dent below seat stay on a steel frame safe to ride?

No, you should not be worried. A dent of that size is probably not a concern on all but the very lightest (and thinnest walled) steel tubing. Surly are economical bikes and use relatively heavy and ...
  • 22.1k
12 votes

Does riding high gear up a hill damage a recumbent bike?

A friend of mine broke a crank (the "arm" of the pedal) in the Alps, so yes, parts can fail under load. It's not always the case that cheap parts fail earlier; sometimes they are actually sturdier: ...
12 votes

Can this crack in the steel chain-side dropout be welded?

You need to consult in person with someone local to you who can make a qualified recommendation. "It is Steel so can be welded" is mostly true, but there are always exceptions. A good welder will ...
  • 106k

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