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Are carbon components safe for the average person?

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Are carbon components safe for the average person?

Old 06-18-20, 12:19 PM
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AL7000
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Are carbon components safe for the average person?

Bought a road bike. The owner adjusted the saddle height for me to test ride and torqued really hard on the seatpost clamp. The seatpost is carbon. Ritchey Carbon Pro 27.2, steel bike frame. Made me cringe watching him crank down on it. Was able to talk the seller down on the price.

When I got home I examined the seatpost. Doesn't appear to have been used with any fiber grip paste. Lots of surface scratches. There is a spot right around where it was clamped that feels kind of flat. Also a slight groove running parallel to the seatpost in the middle of the flat area. Seams to be no deeper than the clear coat. But I could see a crack developing there. If I was to use the seatpost the flat spot/groove would be in the seat tube below the seat clamp a couple of centimeters. However, I just don't trust it.

The seller didn't seem to know or care about torque specifications. The experience made me wonder how safe carbon components are for the average person? Maybe the average person doesn't ever adjust anything on their own and always has the bike shop take care of it for them.















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Old 06-18-20, 12:33 PM
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Carbon bikes are very safe. Just that it cost a little more when you screw them up by doing things as if you were working on a steel bike.

Even steel bikes have people working on them that tighten things till they break.
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Old 06-18-20, 12:45 PM
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For the average person they are safe especially Ritchey products. There are exceptions of course with some cheap, poorly made CF parts. Some people are not average and never bother to learn how to wrench properly and especially with CF parts they need to be torqued to the proper specs so as not the crush and crack them. Hard to tell from the photos if yours is cracked or just deep scratches. Since this person was so ham fisted I would recommend re-doing all of your fasteners just to make sure they aren't over or under torqued which could both lead to ruined parts. I've seen some bike shop mechanics not get it right either so best to learn to do it yourself.
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Old 06-18-20, 01:09 PM
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Originally Posted by Crankycrank View Post
For the average person they are safe especially Ritchey products. There are exceptions of course with some cheap, poorly made CF parts. Some people are not average and never bother to learn how to wrench properly and especially with CF parts they need to be torqued to the proper specs so as not the crush and crack them. Hard to tell from the photos if yours is cracked or just deep scratches. Since this person was so ham fisted I would recommend re-doing all of your fasteners just to make sure they aren't over or under torqued which could both lead to ruined parts. I've seen some bike shop mechanics not get it right either so best to learn to do it yourself.
I have a couple of torque wrenches in varying sizes that I use constantly. I perform all of my own work on my road bikes. I will make sure that I check the fasteners.

It isn't a crack, just deep scratches. I'm guessing the scratches are from the seat tube gaps at the top of the tube digging in due to pressure exerted by the seatpost clamp. Given the reputation of Ritchey products, would this seatpost be safe? I just have a hard time trusting it after seeing the previous owner tighten it down so hard.
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Old 06-18-20, 01:19 PM
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Originally Posted by AL7000 View Post
It isn't a crack, just deep scratches. I'm guessing the scratches are from the seat tube gaps at the top of the tube digging in due to pressure exerted by the seatpost clamp. Given the reputation of Ritchey products, would this seatpost be safe? I just have a hard time trusting it after seeing the previous owner tighten it down so hard.
I wouldn't even want to give you a recommendation on that not being able to see it in the flesh. I usually take chances that others wouldn't on things like this as I know what to look for with potential failures but can only speak for myself.
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Old 06-18-20, 01:38 PM
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Your carbon parts are not safe at all. You should send them to me for proper disposal.
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Old 06-18-20, 01:44 PM
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This is why I will never buy a used carbon bike or parts, excepting possibly if it is obviously like new, barely used, with no damage of any sort. I would replace that seatpost and also carefully check over the rest of the bike.
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Old 06-18-20, 01:52 PM
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AlmostTrick So you'd be okay with buying a used steel, aluminum or titanium bike with damage?

Like you I wouldn't buy a bike that didn't look
like new, barely used, with no damage of any sort.
but it wouldn't matter what it's made of.
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Old 06-18-20, 05:57 PM
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In my average ordinary life carbon fiber is unnecessary ..
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Old 06-18-20, 08:25 PM
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Originally Posted by Iride01 View Post
AlmostTrick So you'd be okay with buying a used steel, aluminum or titanium bike with damage?

Like you I wouldn't buy a bike that didn't look but it wouldn't matter what it's made of.
I wouldn't buy a used aluminum bike with damage and would have to carefully inspect a steel or ti frame. Carbon is a no go if damaged that is for sure unless it is a super valuable frame and Calfee can fix it and I can still make money on it because I have no interest in owning a carbon frame.

In terms of carbon for average people, it is fine if you follow the directions. You can get preset torque wrenches quite easily. If you are not smart enough to follow the simple directions you probably wouldn't be considered quite so average but below that.
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Old 06-18-20, 08:55 PM
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Originally Posted by Iride01 View Post
AlmostTrick So you'd be okay with buying a used steel, aluminum or titanium bike with damage?
Maybe, it depends on the damage. Metal bikes and parts simply are not as fragile as CF.
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Old 06-19-20, 03:26 AM
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Originally Posted by AlmostTrick View Post
Maybe, it depends on the damage. Metal bikes and parts simply are not as fragile as CF.
Carbon just isn't fragile. How could it be?
No one would use it if it was.
​​​​​​
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Old 06-19-20, 04:48 AM
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Originally Posted by blamester View Post
Carbon just isn't fragile. How could it be?
No one would use it if it was.
​​​​​​
Ask all the folks who post "Is this scratch in my CF bike safe to ride, or is it just in the paint" threads. Like this one! OP wouldn't be concerned if this were an aluminum post.

Last edited by AlmostTrick; 06-19-20 at 04:51 AM.
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Old 06-19-20, 05:04 AM
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Originally Posted by AlmostTrick View Post
Ask all the folks who post "Is this scratch in my CF bike safe to ride, or is it just in the paint" threads. Like this one! OP wouldn't be concerned if this were an aluminum post.
Plenty of people ask about scratches on alloy bars or dents in steel frames or the fatigue life of alloy frames or is this tyre safe. It's not exclusive to carbon and doesn't mean the poster is an idiot.
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Old 06-19-20, 05:05 AM
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Originally Posted by AlmostTrick View Post
Ask all the folks who post "Is this scratch in my CF bike safe to ride, or is it just in the paint" threads. Like this one! OP wouldn't be concerned if this were an aluminum post.
Plenty of people ask about scratches on alloy bars or dents in steel frames or the fatigue life of alloy frames or is this tyre safe. It's not exclusive to carbon and doesn't mean the poster is an idiot. I don't mean the op in this case just in general.
Carbon is not dangerous.
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Old 06-19-20, 06:15 AM
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They are safe IMHO. But they need to be treated with care. I mostly tighten everything by feel on aluminium or steel components and never had an issue, but with carbon I think a torque wrench is a must, and I always use it when tightening seatpost clamps, brakes calipers, steems or any other part that involves carbon. I also always use carbon paste when necessary.

This things would put me off from buying a second hand carbon bike, as it's impossible to know what the previous owner has done with it.

When buying a new bike I prefer aluminium as I think it's more durable and reliable long term, and I usually keep my bikes for years.

My opinion is probably not popular, but I feel that the much touted "comfort" of carbon frames is placebo. Tires, wheels, seatposts, and saddles flex way more than a frame and I don't believe frame material can be noticable compared to that. Even a tire pressure change will make a more noticeable difference IMHO.

If I look at the bikes my buddys buy, they tend to prioritize carbon over component quality or total weight and I can't get my head around it. I can't understand why someone would buy a carbon bike with a Recon fork and MT200 brakes, for example, when you can buy an aluminium one with a Reba or Fox 32 / 34 and better brakes at the same price.

The same applies to road bikes. Why buy a carbon bike with low-end components and mechanical discs that ends up heavier than an aluminium one with decent components and hydro brakes? I know there's people who say that "you can always upgrade the components" but, TBH, most people (including myself) don't upgrade the bike except when something breaks or wears down.
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Old 06-19-20, 08:16 AM
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Tightening clamps and fasteners to the correct value is important, but that said, knowing the correct value for the item that's being clamped is often difficult or impossible to know. Clamps have torque values listed on them, but the clamp maker has no idea what you're sticking in it. Those printed values are pretty much just safe values they're indicating the bolts and threads can withstand.

The correct torque value = the least you can get away so that whatever's been clamped doesn't move or loosen.
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Old 06-19-20, 09:25 AM
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Originally Posted by blamester View Post
Plenty of people ask about scratches on alloy bars or dents in steel frames or the fatigue life of alloy frames or is this tyre safe. It's not exclusive to carbon and doesn't mean the poster is an idiot.
Fair point. The main difference is the fact that carbon damage (or defects) are not always visible, and when it does fail it is more likely to be catastrophic.

Far from being an idiot, (your words) the OP was wise to notice the gorilla over tightening of a carbon part, and justified to be concerned about it. I certainly would be!
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Old 06-19-20, 09:44 AM
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Originally Posted by AlmostTrick View Post
Fair point. The main difference is the fact that carbon damage (or defects) are not always visible, and when it does fail it is more likely to be catastrophic.

Far from being an idiot, (your words) the OP was wise to notice the gorilla over tightening of a carbon part, and justified to be concerned about it. I certainly would be!
I edited that because I didn't mean the op. It was in response to veganbikes comment not yours.
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Old 06-19-20, 09:53 AM
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Neither are steel or aluminum defects always visible.

It's really just the ability to fix carbon frames that many can't conceive and then shy from them. Of course since fewer people understand how to repair them, the cost of repairing them may be more. And generally, pound for pound, carbon cloth and resin is many times more expensive than steel or aluminum.

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Old 06-19-20, 10:03 AM
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Not mentioned is it is good practice to turn the seat post clamp around (assuming round) so that the binding bolt is opposite the cut in the seat tube. This spreads the load better around the circumference of the binding area & helps prevent the clamp bolt from levering the unsupported top corners of the seat tube cut into the post & concentrating the load in a very small area.

Carbon does not like concentrated loads. If/when it breaks it will be where the sharp corners dug in to the post. Turning the clamp around helps prevent that.
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Old 06-20-20, 12:16 AM
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My 2c:

Metal frames/parts usually show cracks on the outside, before completely failing.

With carbon fiber parts - it is not the case often enough. However - there are professionals who can properly inspect (and scan) carbon frames/parts to confirm it's all good. It costs, but can be done. With that precaution, perhaps even repeating the checkup in case of any accident, or larger scratches etc, suppose carbon parts are quite safe.

In my country, I don't know of anyone who offers the services of inspecting carbon parts, so for that reason (and the price of both frames, checkups and repairs), I still stay away from carbon components. I often ride without a helmet - but don't really like riding uninspected carbon forks, for example. Without an inspection - the risk is greater than any lower weight benefits, at least for the non-racing me. It seems that even high end manufacturers mess it up from time to time (educational Luescher Teknik videos).
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Old 06-20-20, 08:53 AM
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IMHO carbon is disposable. Not saying that I wouldn't buy carbon, I would...brand new carbon. Buying used carbon is insane, it's even more insane that people pay ridiculous prices for used carbon. The only way to properly inspect carbon is by imaging, like X-ray. Everyone selling used carbon will swear up and down that it was only ridden by a little old lady on Sundays in the park. Meanwhile they've got FG videos of themselves bombing down the Himalayas. Stay away from used carbon, unless you can get it dirt cheap and only expect to salvage some components.
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Old 06-20-20, 05:56 PM
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I haven't seen a slate of carbon failure resulting in injury as a mechanic, so I think the fears people have are misplaced. That said, that post sounds suspect and I'd replace it.
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Old 06-20-20, 09:14 PM
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This is precisely why I'd never buy a used carbon fiber bike or component. You just don't know how ham fisted previous the owner(s) was (were) and what stresses the frame or components have been subjected to.

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