Carbon Frame Strength Test

AmberGold

Picked this up on Bikeradar, it's from 2012 so could have been posted here before. Answers a a few questions about durability and strength of Carbon.

Worth a look.

http://www.pinkbike.com/news/santa-cruz-bicycles-test-lab.html

ZiabR

People always assume things that are lighter must be weaker. Carbon is an exception. If you have the money it is the one to go for.

quozl

For me the down-side to carbon is that you can't tell if it's been damaged by looking at it and that combines very badly with a failure mode of complete collapse rather than metal's buckling.

I'd still rather have a carbon frame but that video doesn't address my (minor) concerns. I've always assumed that carbon fibre frames were very strong.

triggermortis

If they can make aircraft and cars out of CF, I'm sure a bike will be strong enough..

boege

quozl wrote: »

For me the down-side to carbon is that you can't tell if it's been damaged by looking at it and that combines very badly with a failure mode of complete collapse rather than metal's buckling.

I'd still rather have a carbon frame but that video doesn't address my (minor) concerns. I've always assumed that carbon fibre frames were very strong.

As an engineer I have to diagree, the tests show that the failure loads are way higher for the carbon frames. Given all designs have a margin of safety designed in, the tests confirm to me that the probability of a failure for normal design loads is far lower with carbon. Put another way; the carbon will shear if it fails but, based on these tests, it is far less likley to fail.

I once witnessed an accident on a bike once where the front brake calibers came away from the frame (the nut holding them on worked loose- how many of us check that one!!!!!). When the calipers reached the end reach of the brake cable they whipped around, got pulled into the back of the forks, and sheared off the carbon forks. The bike dropped to the road and then the rider went over the bars and hit the road. The accident looked really bad but the rider was not seriously injured (he was hospitalised) as the failure of the forks absorbed some of the forces involved. Had the forks not sheared the riders stop may have been more sudden and the injuries greater.

I work in a university that specialises in testing of carbon joints and joining of carbon components. We also specialise in aluminium. We do a lot of work with the aerospace industry and without any doubt the future is carbon. This is due to its weight advantages but more improtantly due to the ability to manipulate the properties of the material at locations where the loads differ significantly (e.g. bottom bracket).

magicbastarder

triggermortis wrote: »

If they can make aircraft and cars out of CF, I'm sure a bike will be strong enough..

but in relation to cars - generally, you see the panels in high end cars made from carbon, but is the chassis (the load bearing structure) metallic or carbon fibre?

easygoing39

the chassis is carbon fibre on very high end road cars and every formula 1/indy car is made of cf.