# How long do carbon frames last?



## spokesman (Dec 31, 2005)

Do Carbon frames, specifically Tarmac frames, last indefinitely if well taken care of, or is there a limit to the number of miles you can put on one? Rather than get a new bike I might opt for a used one with 7,000 miles on it. If a bike appears to be well taken care of, but has some miles on it, is there anything I should look for or be concerned about?


----------



## crashley6 (Nov 15, 2005)

John Hair said:


> Do Carbon frames, specifically Tarmac frames, last indefinitely if well taken care of, or is there a limit to the number of miles you can put on one? Rather than get a new bike I might opt for a used one with 7,000 miles on it. If a bike appears to be well taken care of, but has some miles on it, is there anything I should look for or be concerned about?



For one, there is no warranty on a used bike. If there was ever a manufacturers defect on that used bike, you are pretty much screwed. I would invest in a new bike just for that reason.


----------



## Koop (Oct 23, 2005)

John Hair said:


> Do Carbon frames, specifically Tarmac frames, last indefinitely if well taken care of, or is there a limit to the number of miles you can put on one? Rather than get a new bike I might opt for a used one with 7,000 miles on it. If a bike appears to be well taken care of, but has some miles on it, is there anything I should look for or be concerned about?


"Carbon fiber composites have a better fatigue life than steel, aluminum or titanium" (Craig Calfee, David Kelly Technical White Paper). Most metal frame failures are fatigue related (barring a catastrophic event like crashing). 

A well cared for carbon fiber frame, one that hasn't been knocked around or crashed should perform as good as new almost indefinitely. The caveat I would add to that is the possibility of UV degradation or resin damage from temperature extremes.

UV degradation is usually mitigated by UV inhibitors in the clearcoat. Thin clearcoat application on a frame that spends many hours in direct sunlight (roof rack or stored outside) can lead to degradation. Waxing a CF frame can also help prevent UV degradation.

Bicycles that are left in a car or enclosed trailer in the summer sun can be subjected to high temperatures. This can also affect the resin used in CF frames.

Both of these issues cannot be detected by simply looking at the frame, so first hand knowledge of the care the previous owner took with the bike is essential IMHO.


----------



## Scot_Gore (Jan 25, 2002)

John Hair said:


> Do Carbon frames, specifically Tarmac frames, last indefinitely if well taken care of, or is there a limit to the number of miles you can put on one? Rather than get a new bike I might opt for a used one with 7,000 miles on it. If a bike appears to be well taken care of, but has some miles on it, is there anything I should look for or be concerned about?


Used Carbon is not that different from other frame materials. Frame dings are your biggest worry regardless of material. A metal frame ding can weaken the tube so it fatigues and breaks, a carbon frame ding can cut fibers that begin to unravel so that it fatigues and breaks. 

The previous comment regarding not being warrantied is a purely individual choice. You have to decide how much "frame insurance" is worth to you. I purchased a used $2000 bike for $1000. If somebody offered me "frame insurance" at the time for $1000 (or even $500) I likely wouldn't have bought so it was worth it to me to take the risk without a warranty. Most frames fail not because of a manufacturers defect but rather because they have a hard impact with a solid object which isn't covered by a frame warranty. When buying used, do your best to make sure it has not had such an experience. 

Good luck
Scot


----------

