36
votes
Why can't a child bike seat be mounted on a carbon frame?
Carbon tubes tend to be very strong at withstanding forces in the direction they are designed for, but weak at resisting other forces (such as clamping forces compressing the tube), hence why bolts ...
- 18.4k
23
votes
What do I do when I am unsure if damaged carbon fiber is safe to use or needs replacing or repairing?
Carbon fiber (CF) composites are made up of sheets of carbon fiber filaments. The key motivation for the question is that they can sustain damage that isn't visible, but that can propagate and later ...
- 35.3k
22
votes
Accepted
Is it worth buying carbon fiber road bike for short commutes?
Comfort isn't really an issue for a 30-minute ride, as long as the bike fits. Also, for any given price point, an aluminium bike will have better components than a carbon bike, so will probably be ...
- 17k
22
votes
Accepted
Recommendations Modifying/increasing a bicycles Max Weight limits
Normally I say bike weight limits are conservative and more about liability and Lawyers than engineering and would have a large safety margin on published weight limits.
However, this frame design ...
- 52.4k
20
votes
Do carbon MTB frames crack easily?
First of all, carbon is stronger than aluminium. It's mechanically on par with steel, while being much lighter. That's why it's the go-to material in aerospace and race cars, and it's also why it is ...
- 3,751
18
votes
Accepted
Does carbon fiber not have a fatigue life?
Fatigue is a concept in metallurgy with a very specific meaning. It is degradation of the crystalline structure of a metal. A metal object or material's fatigue limit is the amount of load it can ...
- 87k
17
votes
Accepted
Is it safe to ride the carbon bike with a small crack on the bottom of the chain stay? Looks cosmetic but fails the tap test
Only the manufacturer or a competent frame repair person can tell you of it is safe. It does not look just cosmetic to me, but I have no qualification whatsoever.
However, this small damage is very ...
- 16.7k
14
votes
Accepted
Why do bikes have carbon forks?
There are an intersection of a number of reasons:
Public Perception - Carbon as that "wow" factor. Colloquial it is associated with "space age" technologies. Therefore it must be better! The ...
- 30.7k
14
votes
Frame dropout cracked, what can I do? (Allied Alfa Disc / carbon)
A crack, unfortunately, is a crack. That’s dangerous no matter what the material. You could contact Allied to see if you have any options in terms of warranty. However, if you didn’t secure the bike ...
- 35.3k
14
votes
Accepted
Little "holes" on carbon rims' profile: what are they used for?
They are drain holes to let water out.
Light bicycle go into slightly more detail on their webpage: https://www.lightbicycle.com/newsletter/Holes-On-Your-Carbon-Fiber-Rims.html
- 18.4k
13
votes
Should I do anything about this minor nick in a carbon fork?
It is superficial, cosmetic paint damage. If that concerns you, you should replace the fork with a aluminum or titanium one. Reason for saying this is you need confidence in you bicycle to enjoy ...
- 52.4k
13
votes
Carbon chainstay damage assessment
That does not appear to be damage, in as much as it conspicuously appears to be the shape of where a chainstay chain-slap protection sticker was originally placed. what you are possibly seeing is the ...
- 6,477
13
votes
Cracked Carbon Seat Tube
This is definitely a job for a carbon repair expert, not something you can fix at home with some epoxy and sand paper. It also looks like there is a crack propagating lengthwise through the top tube?
...
- 28.8k
12
votes
carbon vs aluminium frame vibration absorption? bumpiness?
Aluminum has gotten a bit of a bad reputation from the early generation of frames which were overly stiff. This is less the case today as manufacturing technology fixed most of these earlier problems, ...
- 30.7k
12
votes
Scratch or damage on carbon frame
That's just a light scratch. No issues.
if you are worried that the carbon-fiber composite has been damaged by an impact or scratch, the abrasion is far too shallow for that. It has not even ...
- 75.9k
12
votes
What's the best way to stow (winter storage) an all-carbon bike?
I don't see a problem hanging a bike from a carbon fiber composite rim. The amplitude of the load would be much, much lower than when riding over even moderate bumps. OK, the load is radially outward ...
- 75.9k
12
votes
Are these shallow gouges and imperfections on a new carbon fork steerer benign or serious?
I don't normally go around inspecting fork steerers, but I suspect that's highly abnormal and a significant cause for concern.
I don't clearly see torn fibers. If you did, that should mean the steerer ...
- 35.3k
12
votes
I'm not sure if a torque wrench was used in assembling my carbon bike
He is unlikely to have damaged anything unless he's a complete gorilla.
Loosen off any bolts or bolt pairs that you are concerned about, then do them back up to torque.
- 15.3k
12
votes
Accepted
What's the difference between more or less expensive carbon wheels?
First, I wouldn't recommend buying from Aliexpress brands that you don't know at all. These may be resellers getting rims from the same factory, and they may be difficult to reach for product support. ...
- 35.3k
12
votes
New carbon road bike - scratches discovered on chain stay
Chains can slap against the chainstay. With the condition of roads in the modern United States, it’s almost guaranteed - I can only speak to this country and to Singapore, which doesn’t have freeze-...
- 35.3k
12
votes
Accepted
What are the risks of a compromised top tube and of attempts to repair it?
I've rewritten my answer since the question was extensively edited.
I'll preface this by saying that I'm by no means a qualified carbon fiber repairperson, just someone with some minimal knowledge ...
- 16.9k
11
votes
Accepted
Can I use brake pads for carbon wheels with aluminum wheels?
In short yes you can, carbon brake pads will stop you but you shouldn't. Firstly the brake pads will not be as effective on the alu rims. Secondly the change between alu and carbon rims could be risky ...
- 1,136
11
votes
Accepted
Do I need to apply something on thru axle?
I usually put a very small amount of grease on the threads at the end so that it will be easier to remove when you need to take it out again. As with all threaded connections these tend to seize-up ...
- 978
11
votes
Accepted
Chain damaged carbon frame. How to remedy?
It's very likely only cosmetic, but the fine hairline-looking scratches (hopefully only scratches) are not the most common thing to see in damage that occurs from a dropped chain.
The other thing to ...
- 87k
11
votes
Attachmentpoint rim brakes carbon bike, sratches/crack?
The frame is cracked and should be repaired. It's likely nothing to do with the crash, unless perhaps the brake was impacted. This could result from the recessed nut either being overtightened, from ...
- 87k
10
votes
Accepted
What are these mounts for on inside edge of carbon fiber fork?
They're for full fenders. Many disc road and fitness/urban/hybrid bikes now have them here in order to completely avoid strut interference with the brake. To install the fenders neatly I've been ...
- 87k
10
votes
Crack in fork or just paint
I'm sorry to say that looks like a crack rather than a scratch.
Bike looks quite new (I notice the dual pivot calipers), but I believe Trek's lifetime warranty covers CF frames and forks beyond 5 ...
- 75.9k
10
votes
Accepted
Crack in fork or just paint
On the surface it doesn't look good, but I wonder if there is a reinforcement wrap for the brake posts, with an unfinished edge). There are some informal ways to try and confirm whether the structural ...
- 30.7k
10
votes
Cycled through pothole on carbon frame - damaged?
CFC frames are not as fragile as many people seem to think they are. If you got a heavy jolt but didn't feel like you were going to be thrown off the frame is probably fine. I'd be more immediately ...
- 75.9k
10
votes
Accepted
Does this carbon fork have a crack in it that would make you replace it?
What is visible in the photo is a paint scratch. Letting the bike simply fall over will not structurally damage carbon fiber composite. People seem to think CFC is fragile but it’s really quite robust....
- 75.9k
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