Post mount disc brakes - cracked carbon

[pclay]

hi, I have a carbon fork on my CX bike, which has post mount brakes. I was giving the bike a good clean (in readiness for selling it), and I noticed what appears to be a crack in the underneath of the post mount for the brake. Is this a crack in the carbon, and is this now a dangerous bike to ride/sell?

Should I still try and sell the bike complete (being honest with the 'fault') or strip it down for parts a buy a new frame/bike? Thanks

 

[Tangoup51]

To me, it looks like a nasty gouge rather than a crack. That's right on the underside of the bike at the front end, it can catch debris especially offroad.

Clean it up as much as you can and see if the crack spreads to the alloy insert thread.
Also try to torque down the caliper against it, see if the 'crack' flexes or opens in tension.

Try the 'penny' test aswell, by tapping a penny against it. - cracked carbon has a dull pitch when hit, where-as working carbon is higher and sharper and easily noticeable by ear.


Also, you don't have to scrap the frame because the front fork may be kaput. You can just buy a new fork

 

[Cycleops]

It's really up to you but any of the two options you mention would be fine.

 

[I like Skol]

As tangoup says, could just be a scratch. Tightening something onto it just by that bolt and giving it a bit of a tug to see if the 'crack' opens up under force would be the acid test for me.

 

[Smokin Joe]

Just a scratch. That's a thick piece of carbon there, I would say it is highly unlikely to crack. We can get a bit paranoid about CF, if it was steel you wouldn't give it a second glance.

 

[I like Skol]

Did a CX race on my carbon bike today and in horrendous conditions. It didn't melt or break, just sayin....

 

[Levo-Lon]

Well its a threaded insert that may have been stressed in a off or impact, but it will probably be fine.
As said mention it and see how it goes..
It's a fork so it's easy to replace and most people would take that as seen

 

[Cycleops]

Just a scratch. That's a thick piece of carbon there, I would say it is highly unlikely to crack. We can get a bit paranoid about CF, if it was steel you wouldn't give it a second glance.

That’s not how a prospective buyer might view it, expect to come down somewhat in price.

 

[Tangoup51]

That’s not how a prospective buyer might view it, expect to come down somewhat in price.

If it can be confirmed as a scratch, a prospective buyer won't have to see it because it can just be filled & painted.

 

[pclay]

Thanks, I am selling the bike as it's a bit too small for me / too aggressive. I will mention this 'scratch'.

I put the brake back on and tightened the bolt, there was no movement in the scratch, and I can't get it to open up by yanking on it.

I was wondering weather to strip the frame as it has brand new wheels and a 105 10speed groupset. The bike is on,y worth about £350 if that. It's a Saracen Hack 2 2014. I could buy a croix de fer fra set and transfer everything across.... decisions.

 

[Smokin Joe]

Thanks, I am selling the bike as it's a bit too small for me / too aggressive. I will mention this 'scratch'.

I would not consider it worth mentioning. On a second hand bike it constitutes no more than fair wear and tear. When you buy a used car the seller does not point out every little stone chip or scratch on the paint nor would you expect them too. There is no structural damage and if the buyer is so fussy that a light scratch that cannot be seen without upending the bike would put him off then it is up to him to find it.

You are not hiding anything untoward, don't go putting doubts into the buyers mind and risking the sale.

 

[Tangoup51]

Thanks, I am selling the bike as it's a bit too small for me / too aggressive. I will mention this 'scratch'.

I put the brake back on and tightened the bolt, there was no movement in the scratch, and I can't get it to open up by yanking on it.

I was wondering weather to strip the frame as it has brand new wheels and a 105 10speed groupset. The bike is on,y worth about £350 if that. It's a Saracen Hack 2 2014. I could buy a croix de fer fra set and transfer everything across.... decisions.

That is a scratch. That is not an issue. You will make it an issue if you put a stage light on it with most sellers being paranoid sceptics, so they're going to have an absolute field day with your scratch. Probably tell you it's something it's not to get you to fork over a 55% discount.

Bottom Line. If it's not a problem, don't make it out to be one.

Also, even lower than bottom line, no one looks for a second hand bike without a scratch.

 

[biggs682]

@pclay well done for being upfront about it , nice bike