Carbon fork life span?
 

Hello All:
A friend of mine rides a Ti Serotta with a Time carbon fork. That fork has been ridden for over 20 years now. She's a fairly light rider and rides only paved roads. The fork shows no signs of damage that I can see. Even so, should I consider replacing it just to be cautious?
Cheers,
Jim

I would not rely on blind guessing from this forum.

CF hasn't been in use on bicycles long enough to properly determine a life span and so far it's shown to be a good material in spite of some very early negative predictions. Time CF forks were well regarded at the time, BTW.

Unless I find some damage to my CF forks from that era, and that damage is spreading, I'm not going to fret over them.

Brad

Right. I'm actually in the process of locating a replacement. My question really is are the so reliable that I shouldn't bother replacing it.

It can look good but still have delaminarion and loose bonding of the carbon to the aluminum parts..

You have to remove it and have an expert Eye Inspect it.

What is relevant here is the usual failure modes for CF composite material.
UV exposure is one of the main root causes for CF deterioration, severely harming the epoxy.

If the fork has been in use for 20 years and ridden often, resulting in lots of UV exposure, the smart move is to replace it.
If it instead has been ridden seldom during its lifespan, I see no reason for concern.

Sample size of two: I have Easton EC90SLX all-carbon forks on two bikes that are both 11 years old and have been ridden 41,000 miles and 38,000 miles respectively. So far there is not the slightest sign of cracks or delamination with either. I do check them periodically for defects and have found none so far. Also, these are among the lightest carbon forks I know of (295 grams before cutting the steerers to length) so they certainly aren't overbuilt.

I've also wondered about proactively replacing them but haven't so far.

Except the fork would have a UV protecting clear coat on it. If the clearcoat is not hazed or cracked all over, there's very little chance of under-lying UV degradation.

Given the fork a good inspection. If it looks good there's no need for concern. Look for cracking around the steerer and at the dropouts in particular.

Carbon has a theoretically infinite fatigue life. Most failures will be due to either manufacturing defects or crashes. At 20 years, if a defect was going to cause issues, it would have happened. Unless you have some reason to suspect impact damage, I don't see a reason to replace it.

I'm with gsa103 and bradtx. If I examined the fork and didn't see anything wrong with it, I'd keep riding it.

If you insist on tossing it, you can send it to me for proper disposal. ;-)

Well, 20 years is a lot of time. As someone above said it comes down to a lot of factors, net ridetime, UV exposure, woring etc. Anyhow (depending on the brand and making of course) carbon forks are very reliable; on the contrary of carbon frames.

In my country we don't have actual pro cycling stores so many of my friends have times recycled carbon forks, which I don't know if come to 20 years but have changed owenrs at least ten times. No doubt the perfect thing to do would be get a new fork and toss this veteran but If it were up to me I'd keep using it.

Many folks believe that carbon fiber degrades over time, as the resin component of the matrix gets brittle with age.

But it's hard to prove this (real world conditions vary widely), especially since each company may use a slightly different resin recipe.

One thing I know for sure: if the Ti Serotta has a 1" steerer, you're going to have a hard time finding a replacement CF fork that isn't as old as the one you already have.

1 1/8" forks are definitely more common, but Google turns up more 1" options than I would've guessed. Here are a few of 'em:

Tifosi 1" Carbon Fork from Wiggle
Origin8 1" Carbon Fork from Bikewagon
Nashbar 1" Threadless Carbon Fork
Nashbar 1" Threaded Carbon Fork

Unless the OP insists on a carbon steerer, Nashbar sells a carbon fork with an aluminum steerer in 1" threadless for $105.

Nashbar Carbon Road Bike Fork

I recently installed one of these on a 1" steerer 1996 Litespeed Ti frame using a Cane Creek 40 threadless 1" headset and a 1-1/8" stem with a reducer bushing. The combination works very well and the conversion cost was reasonable.

Replaced the OEM fork on my Lightspeed after bouncing the bike off the hood/bumper of a car and warping both wheels and
trashing the body of a Frog pedal. Fork looked ok and rode ok for several hundred miles after replacing the wheels but at
11 yrs and 23k miles and a desire to add an inch to the handlebar height I used one of the Nashbar aluminum steerer CF
forks ($75 with coupon). Oddly, both CF bars I used a few yrs ago had paperwork suggesting a "3 yr lifespan" when replacement was recommended.
I do think there have been improvements in fork manufacturing tech over the past 20 yrs and since the consequences of a fork
failure are catastrophic to the rider, replacement is prudent.

Those are all pretty heavy.

This one is about 330g, IIRC.

wiggle.com.au | Columbus Minimal Road Forks | Road Forks

If you're concerned, the conservative thing to do would be to replace it.

Personally though, I'd feel just as comfortable on an original Time fork as I would on a new low-cost, Chinese made fork of unknown provenance from Nashbar.

Yeah, the fork is probably fine for another twenty years or more.

The most typical age-related failure I've come across with carbon is when it's bonded to aluminium that hasn't been anodised properly, and galvanic corrosion has destroyed the bond. I would expect better from Time.

It is interest that searching "Carbon Fiber Lifespan" on Google, the first two pages of results are about bicycles. It was on the third page where a couple of other CF items appeared.

The cycling world may be trying to pinpoint the eminent CF assplosion.

That's not a bad weight but the 1" version is out of stock and I wouldn't be surprised if it's out of production. Also, a bit pricy compared to the other ones that have been listed but for a Serotta that may not be a problem.

Customer brought in a Colnago today, ally with carbon stays and fork, the latter with its steerer snapped off (a car was involved).

The replacement fork he brought in with it? Brand new Columbus Minimal 1".

The point about failure mode is key. If the matrix (e.g the glue) is protected (painted) from UV and not degraded, and the fibers themselves are not nicked or cut, CF has a much higher fatigue limit than steel. But a nick or gash that cuts some fibers is going to be a big stress concentrator. Or hitting a bump and getting some delamination inside the fork may create an unsafe fork.

I guess if it's not nicked or cut, and the "coin test" gives bright, clear clicks all round, I'd continue to ride it. But if you're worried about it, that makes cycling less enjoyable. That would involve a personal choice to replace.

Me too. More so.

And of course it doesn't fit any of your, er um disposal sites, you'll send it on to me, right? :thumb:

Brad

Is "she" concerned about the fork at all?

This tread inspired me to do a little reading. If you google 'carbon fiber UV damage' the third item that comes up is a pdf of a paper (Kumar is first author; I'd link to it but it's a pdf). What this paper found is that there is a synergistic effect between UV and moisture exposure, with the combination greatly speeding up the loss of CG strength in the support matrix. Basically, real world bicycling conditions are bad for unprotected CF (yes, I realize they only tested one particular CF formulation) unless you live in a very arid environment.

For CF forks with a good UV-blocking clearcoat, or even better, a good paint covering, this is largely irrelevant. But it made me think about CF handlebars, which are exposed to the sun (and moisture and sweat) at their most vulnerable portion (around the stem clamp). Bars are rarely painted, and whatever clearcoat many of them have also seems very thin, and could easily be worn off my routine handling.