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 ...
leftaroundabout's user avatar
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 ...
Ted Hohl's user avatar
  • 6,142
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? ...
Michael's user avatar
  • 27.4k
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 ...
Nathan Knutson's user avatar
9 votes

Should I upgrade my entry-level bike?

Shopping advice of off topic, so I am not making a recommendation on make/brand/model. If you are unhappy with your current bike, first thing is work out why - is it the quality of the bike, or the ...
mattnz's user avatar
  • 50.5k
9 votes

Wear marks on seat stay from fender/mudguard. Problem?

You have worn right through to the carbon, and possibly into it. There is a school of thought (stress testing by Reynolds) that the seat stays don't do very much. This may go against logical thought. ...
Noise's user avatar
  • 13.9k
8 votes

Do carbon MTB frames crack easily?

Carbon frames are just fine. As with any other frame materials they are designed to take the loading and stress of normal riding for their intended purpose. That isn't to say they can't be damaged if ...
Hursey's user avatar
  • 705
8 votes
Accepted

Are cleat backing plates for protecting carbon sole?

I've only used cleat backing plates to shim out the cleat away from my foot when the sole or lugs of the shoe were interfering with cleat engagement. I've put carbon-soled shoes from a couple of ...
Paul H's user avatar
  • 4,102
7 votes

At what level of carbon fiber damage should you have it checked at your LBS?

Although one cannot make a definitive judgement based off a few photos, I think in this case it is exceedingly safe to say that this damage is not a problem. Scraping your bike against a fence is ...
MaplePanda's user avatar
  • 15.5k
7 votes

Glue for carbon fibre

If it's a repair to something structural, simple glue won't be strong enough. The strength comes from the fibres, and if they're broken, you have a very weak spot. In the general case, which glue to ...
Chris H's user avatar
  • 58.9k
7 votes
Accepted

Shallow ring of death

The video is from an internet personality who a) behaves extremely problematically, b) has no engineering training, and c) has a thing about carbon fiber. Raoul Luescher is a much more credible source ...
Weiwen Ng's user avatar
  • 31.5k
6 votes

Carbon rim depth - 44 or 56mm?

Per the FAQ, we don't make product recommendations. However, crosswind stability is a significant consideration. Here, you are probably better with the shallower wheel. Ronan McLaughlin discusses the ...
Weiwen Ng's user avatar
  • 31.5k
6 votes

Can large bike size will be solved by replacing the crank arm with a longer length?

The frame size of the bicycle is designed according to the rider's height and inseam length to ensure a suitable and comfortable pedaling. Swapping the crank arms to shorter or longer ones can adjust ...
Gary's user avatar
  • 121
6 votes

How to repaint a Carbon bike frame?

Although I appreciate the word of caution that the others are providing it is a simple process to paint carbon. I've done it 3 times now at home. Sand just enough to get through the clearcoat of the ...
moreseun's user avatar
6 votes

Attachmentpoint rim brakes carbon bike, sratches/crack?

I realized that i have a Rose service Partner in town. I brought the Bike there to See If my 6 year frame warranty needs to be used. They inspected again and said: Cracks are in Paint Job. Carbon and ...
roverhendrix's user avatar
6 votes

Noticed a small scratch in the integrated crown race of my carbon fork. How fragile is this part of the fork?

That scratch/indent looks absolutely tiny and harmless. As for the aluminium pieces: As coincidence would have it I recently took my fork out because of creaking noises as well. I was quite surprised ...
Michael's user avatar
  • 27.4k
6 votes

Wheel scratched carbon on ride

I don't see any frayed carbon fibers, nor any cracks propagating from the worn area. I've raced on a bike with much worse tire rub on its seat stay - again, with no frayed carbon fibers or cracks - ...
Andrew Henle's user avatar
  • 10.6k
5 votes

Carbon Damage on bridge, repair possible? If so, what steps are needed?

Ultimately only the repair places can say. It needs to be inspected with tools that you don't have to make the call. My guess is this will require replacing the whole bridge, which might not be ...
Erik H's user avatar
  • 369
5 votes
Accepted

Should I use fiber grip or grease when installing a bottom bracket into a carbon frame?

Grease. Allows the parts to come together smoothly, allows the threads to glide properly, seals out water, prevents corrosion, makes sure you can remove the parts again later. Carbon assembly paste ...
Michael's user avatar
  • 27.4k
5 votes

Is it possible to prove that applied forces to a top tube are worse than a seatpost when using a repair stand clamp?

With all the math in the world this can't be proved generically because we don't know anything other than the top tube is carbon. It being carbon says nothing about wall thickness, shape, or ...
Nathan Knutson's user avatar
4 votes

Unsure if my carbon steerer got damaged from riding with stem attached in wrong position

Although I can't make guarantees, most of the time, the "do not leave space above the stem" clause refers to empty space. As in, ensure the steerer goes all the way through the stem clamp. ...
MaplePanda's user avatar
  • 15.5k
4 votes

Can large bike size will be solved by replacing the crank arm with a longer length?

Maybe - a longer crank arm lets your foot go lower, permitting the saddle to be a little lower. But it also forces your opposite foot to move higher to complete the circle, and that may not be ...
Criggie's user avatar
  • 124k
4 votes

Do you agree it's safe to continue to ride this carbon bike with a small crack in the frame?

Bruh originates from the pronunciation of bro in African American English. In modern internet discourse, it has morphed into a multipurpose interjection that can convey, among other things, disbelief ...
Weiwen Ng's user avatar
  • 31.5k
4 votes
Accepted

Scratch in the very top of a new carbon steerer tube. Should I worry about this?

Initially, I thought this might be a void that's at the surface. I believe that there is always the chance of a void, or a hole, in carbon fiber, but good manufacturing will minimize the incidence of ...
Weiwen Ng's user avatar
  • 31.5k
4 votes

Confidence in carbon bike frame after sealed bearing replacement

Servicing press fit bearings is expected periodic activity. The bearings are designed to be installed and removed, and the bike frame is designed around this expectation. A part of the frame design ...
mattnz's user avatar
  • 50.5k
4 votes

Carbon Damage on bridge, repair possible? If so, what steps are needed?

Well i got a response from a few bike repair shops: it is a crucial spot. The bridge would need to be replaced in total. This is not doable without the part for the repairshops. So, frame goes in the ...
roverhendrix's user avatar
4 votes
Accepted

I suspect that my carbon fork has a crack but I can't really tell

This question and the answer will probably help some, and the answer includes photo examples of types of damage. The steerer ring of death photos may be a helpful reference. In this case, I don’t ...
Weiwen Ng's user avatar
  • 31.5k
3 votes

Glue for carbon fibre

The best bonding of carbon fiber comes from using a two-part, epoxy resin (polyepoxides). When the polyepoxides resin is combined with a co-reactant resin, also known as a hardener, it results in a ...
Jeff's user avatar
  • 10.2k
3 votes

Confidence in carbon bike frame after sealed bearing replacement

I am far too sleepy at the time of this writing to start calculating peak forces and stuff, so let's approach this more casually. To begin, it should immediately be obvious that getting your bike run ...
MaplePanda's user avatar
  • 15.5k
3 votes

Confidence in carbon bike frame after sealed bearing replacement

Consider that the forces to remove a bearing should be about the same magnitude as the forces required to install it initially. Maybe less, maybe a little more, but not 10x as much. If the ...
Criggie's user avatar
  • 124k

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