Carbon Fork replacement interval/duration ?

[Adam-from-SLO]

Hello All,

Can anyone tell me if there is a common practice in removing/replacing your Carbon fork every "X" amount of years / or miles ? OR.... inspect it monthly,etc. ........ and if a crack develops, etc. ........ then replace the fork ? No doubt, safety first..... and ones front fork is a vital line of defense against being safe. Any personal experiences here would be very benificial.

Thanks in Advance.

 

[Insight Driver]

Hello All,

Can anyone tell me if there is a common practice in removing/replacing your Carbon fork every "X" amount of years / or miles ? OR.... inspect it monthly,etc. ........ and if a crack develops, etc. ........ then replace the fork ? No doubt, safety first..... and ones front fork is a vital line of defense against being safe. Any personal experiences here would be very benificial.

Thanks in Advance.

After many months of reading about carbon fiber composite products, failure modes, strength and many myths that fly around the internet the straight answer is, you don't have to change your carbon fiber fork unless you have crashed it or scratched it deeply in some accident. Unlike metals, carbon forks do not fatigue with age and carbon composites are so strong and overbuilt to be safe that you may wear out everything else on a bike except that fork. What you will find a dearth of is personal experience of fork failures since there are very, very few instances of fork failures that were not the result of a severe accident of some kind prior to failure.

 

[capwater]

The only thing I've run across is a carbon fork where the lugs started to separate from the carbon. Not sure of the material, some sort of metal (magnesium?). This was an ex pro race bike that had been heavily used so not your average amateur ride. That being said, Klein covered the full cost of replacement for my bro.

 

[Insight Driver]

The only thing I've run across is a carbon fork where the lugs started to separate from the carbon. Not sure of the material, some sort of metal (magnesium?). This was an ex pro race bike that had been heavily used so not your average amateur ride. That being said, Klein covered the full cost of replacement for my bro.

I spent a long time searching for "carbon fork failure" and all the links I found are only talking about the potential. I have yet to find one article that details a particular carbon fork failure other than ones that were damaged something, nothing from product defects or fatigue failures.

 

[Adam-from-SLO]

I spent a long time searching for "carbon fork failure" and all the links I found are only talking about the potential. I have yet to find one article that details a particular carbon fork failure other than ones that were damaged something, nothing from product defects or fatigue failures.

Thanks for the info everyone.... thats pretty much what I figured.

Also, what about the differences between Carbon forks that are:
*ALL Carbon
*Cro-Moly steerer, carbon legs
*Alum. steerer, carbon legs

IS there any inherently better/worse designs out there were the fork legs/steerer interface is ???

Thanks again.

 

[Jaguar27]

I spent a long time searching for "carbon fork failure" and all the links I found are only talking about the potential. I have yet to find one article that details a particular carbon fork failure other than ones that were damaged something, nothing from product defects or fatigue failures.

I must confess, I was a little concerned about the Carbon Forks with Carbon steerer and drop-outs when I first bought my Bike, plus I'm 200Lbs...But no problems thus far after 3500 miles...


I do think they should be inspected periodically though...just like mine haven't

 

[531Aussie]

what about the differences between Carbon forks that are:
*ALL Carbon
*Cro-Moly steerer, carbon legs
*Alum. steerer, carbon legs
.

the biggest difference with an all-carbon fork is the weight; you can expect to drop at least 150g if you swap from an alu to a carbon steerer. Also, I've only used 4 full-carbon forks, and they've all been more comfortable than my carbon forks with cro-mo and alu steerers. I'm not sure if this is due to the carbon steerer having more flex, or due to other design factors.

Some pros use alu steerers on the Belgian cobbles for "extra strength".

Pretty hard to find new carbon forks with cro-mo steerers unless they're 1" threaded.

 

[hd reynolds]

The one area that I think should be inspected over time are the ones where CF is bonded to another metal specially w/ aluminum or steel. Unlike titanium, these metals oxidize or corrode affecting the integrity of the fork.

 

[Adam-from-SLO]

The one area that I think should be inspected over time are the ones where CF is bonded to another metal specially w/ aluminum or steel. Unlike titanium, these metals oxidize or corrode affecting the integrity of the fork.

I didn't think Alum. oxidizes... or corrodes ???

Or .. is it, ANY metal exposed to air- can over time oxidize.... right

 

[hd reynolds]

I didn't think Alum. oxidizes... or corrodes ???

Or .. is it, ANY metal exposed to air- can over time oxidize.... right

Aluminum oxidize.

On another note, you can leave titanium outside with the elements for a 100 years and it will look the same as the day you left it

 

[Adam-from-SLO]

Aluminum oxidize.

On another note, you can leave titanium outside with the elements for a 100 years and it will look the same as the day you left it

Gotcha !

I guess when you see empty Alum. beer/soft-drink cans on the side of the road... after X amount of months, they DO severely become brittle

I remember Kestral use to produce there Carbon EMS fork w/ a Ti. steerer

 

[artmichalek]

Aluminum oxidize.

On another note, you can leave titanium outside with the elements for a 100 years and it will look the same as the day you left it

The oxide layer that forms on exposed aluminum is protective. It prevents the metal from oxidizing further, like steel. This is what anodizing is. Exposure to corosive substances like salt is another story. The problem with some aluminum dropouts on carbon forks is that aluminum and carbon have different galvanic constants. If the two materials are in contact and there's any sort of moisture, an electric current flows between them and the aluminum corrodes badly. Most manufacturers of frames and forks use a layer or two of fiberglass to isolate the carbon from any bonded inserts.

As for fatigue, it does happen in carbon fiber composites. The mechanism is kind of similar to metal fatigue, but on a bigger length scale. It's not something to really worry about though, since most carbon parts get destroyed in crashes or upgraded long before this occurs.

 

[Adam-from-SLO]

Here is my issue.

I just bought a FULL carbon fork off a seller on Ebay(not going to mention the brand of fork... or the sellers name). Fork was sold as "used for one year, by a woman".

I recieved the fork, inspected it(some small chips- covered w/nail polish - no big deal). However, there is a small 20mm section to the upper part of one fork leg, just about at the crown, where the clear coat has cracked. The length goes from inside the leg-towards the outer-backside of the fork leg(horizontally). Not sure how this "clear coat crack" could have happened ???

I'm not 100% sure this fork is ride-able , thus do you all think it would be best for me to send the fork back ? I had my LBS inspect it today, and the one worker that was there said "send it back.... I would not take any chances with it".

 

[capwater]

When in doubt, throw it out!

Here's my .02. Would you risk your life or serious injury on a fork failing? There is no amount of money saved that would give you peace of mind. I did buy a used CF fork off a buddy. He was the original owner and got hit sideways in the rear, actually broke the CF rear triangle. Front of the bike was fine and since I knew this guy and the real details of the crash I was comfortable buying it used. The tag line "just riden by a small recreational woman rider" is akin to the car line about a vehicle "just driven by a little old lady on Sundays to church."

 

[artmichalek]

I'm not 100% sure this fork is ride-able , thus do you all think it would be best for me to send the fork back ? I had my LBS inspect it today, and the one worker that was there said "send it back.... I would not take any chances with it".

It's entirely possible that the fork had been moved rapidly between warm and cold environments and it's just an expansion crack in the clear coat. I would be willing to wager about $3 on that possibility. If you value your life at more than $3, send it back.

 

[capwater]

Adam: You already know what you should do dontcha .........

 

[Adam-from-SLO]

Adam: You already know what you should do dontcha .........

Paul,
Yeah..... its the last time I buy USED carbon fiber on Ebay. The fork might be fine for 1-2K miles...... 100-200 miles....... 1-2 miles...... 1-2 feet , then snap on me , which is not worth risking my health over some carbon fork.

I just emailed the seller to let him know what I've found out. I should have it back out to him in 1-2 days.

 

[Deanster04]

Paul,
Yeah..... its the last time I buy USED carbon fiber on Ebay. The fork might be fine for 1-2K miles...... 100-200 miles....... 1-2 miles...... 1-2 feet , then snap on me , which is not worth risking my health over some carbon fork.

I just emailed the seller to let him know what I've found out. I should have it back out to him in 1-2 days.

Contact the seller and ask for your money back. You might be surprised. Also, you can try and arbitrate your problem. Hope you didn't jump the gun and give a positive response to the feedback.
Before you get mad and negative contact the seller with what you bought. I have only been stiffed once and it turned out that the seller was doing a friend a favor by listing the item. When I sent pictures to the seller he was horrified and refunded the money and the shipping cost. Most people are honest. Use the feedback as intended, but communicate first.
I wouldn't use the fork.
For lifetime I would worry about the dropouts if they are Al and stress fractures. Just don't over tighten the skewers.

 

[Adam-from-SLO]

Contact the seller and ask for your money back. You might be surprised. Also, you can try and arbitrate your problem. Hope you didn't jump the gun and give a positive response to the feedback.
Before you get mad and negative contact the seller with what you bought. I have only been stiffed once and it turned out that the seller was doing a friend a favor by listing the item. When I sent pictures to the seller he was horrified and refunded the money and the shipping cost. Most people are honest. Use the feedback as intended, but communicate first.
I wouldn't use the fork.
For lifetime I would worry about the dropouts if they are Al and stress fractures. Just don't over tighten the skewers.

The seller has already left pos. feedback for me, and I have yet to leave feedback for him.

The seller has contacted me back, with clearence to ship him back the fork- for a full refund He has admitted to have not seen the break in the carbon clear-coat. REally, its been great communication with him the entire time ! I'm shipping back tomorrow !

DOES ANYONE know of where I can find a NEW LOOK HSC-2 full carbon fork 700c for sale ?? I believe this fork came out in 1998/9 ........ , and has in the last 1-2 years been replaced with the new LOOK full carbon fork, which is ONLY 1 1/8" . I need a 1" fork.

 

[Deanster04]

The seller has already left pos. feedback for me, and I have yet to leave feedback for him.

The seller has contacted me back, with clearence to ship him back the fork- for a full refund He has admitted to have not seen the break in the carbon clear-coat. REally, its been great communication with him the entire time ! I'm shipping back tomorrow !

DOES ANYONE know of where I can find a NEW LOOK HSC-2 full carbon fork 700c for sale ?? I believe this fork came out in 1998/9 ........ , and has in the last 1-2 years been replaced with the new LOOK full carbon fork, which is ONLY 1 1/8" . I need a 1" fork.

Glad things are working out. Don't forget to leave him positive feedback when you get the refund about his honesty and good communication. It is important when you are a seller, especially when you honor your policies.