Cracked carbon around BB shell. Salvageable? Can I ride it?
Moderators: robbosmans, Moderator Team
So today I noticed a rather nasty crack around my BB shell. I think it may have been there for some time undetected. I raced on it today with no issues (bar a few creaks) and have two races booked next weekend. I'm desperate not to miss them and won't be able to sort out a replacement frame in time. Am I safe to ride it? Also is something like this legitimately fixable, or is it just a case of bodging as a temporary measure?
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I had something very similar with my Cannondale Supersix. In all probability it had been there a while and was raced/ridden for quite a while before it properly broke (it was an eBay purchase so no chance of a refund). The carbon repair specialist I took it to had a good look and declared it unfixable. It is still sitting in my shed...
The most annoying thing was that the weekend before it properly broke I finished a close 2nd in a road race not realising I was riding a cracked frame...
The most annoying thing was that the weekend before it properly broke I finished a close 2nd in a road race not realising I was riding a cracked frame...
- bikerjulio
- Posts: 1900
- Joined: Fri Dec 11, 2009 10:38 pm
- Location: Welland, Ontario
It's a high stress area where the alloy BB insert bonds into the frame.
When it breaks, you'll probably experience a wobbly crank. So, I don't see a failure as life threatening but could be noticeable.
When it breaks, you'll probably experience a wobbly crank. So, I don't see a failure as life threatening but could be noticeable.
There's sometimes a buggy.
How many drivers does a buggy have?
One.
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.
http://www.youtube.com/watch?v=GekiIMh4ZkM
How many drivers does a buggy have?
One.
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.
http://www.youtube.com/watch?v=GekiIMh4ZkM
I'm pretty ready to call it a day with this frame so have no issue running it into the ground while a replacement arrives (BMC is calling me...) As long as it lasts me until this then I don't mind too much; providing failure doesn't risk crank touching tarmac and testicles touching top tube...
I'm not an expert on this, and don't know if it would work....
Since the frame is destined for the scrap-bin, if you MUST ride it in the meantime... I'd try:
- Sand the CF all along the crack area
- Use a two-part epoxy, force the epoxy into the crack as best you can.
The sanding was to give the excess epoxy something to grab.
Work FAST with the epoxy. It heats as you mix it, the hotter it is, the easier it will be to flow it deeper into the crack.
Since the frame is destined for the scrap-bin, if you MUST ride it in the meantime... I'd try:
- Sand the CF all along the crack area
- Use a two-part epoxy, force the epoxy into the crack as best you can.
The sanding was to give the excess epoxy something to grab.
Work FAST with the epoxy. It heats as you mix it, the hotter it is, the easier it will be to flow it deeper into the crack.
- bikerjulio
- Posts: 1900
- Joined: Fri Dec 11, 2009 10:38 pm
- Location: Welland, Ontario
I had a similar situation.
Buy this epoxy.
Drill small holes at about 1/4" increments around the crack. just through the carbon - not the alloy sleeve.
Pump in the epoxy.
Buy this epoxy.
Drill small holes at about 1/4" increments around the crack. just through the carbon - not the alloy sleeve.
Pump in the epoxy.
There's sometimes a buggy.
How many drivers does a buggy have?
One.
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.
http://www.youtube.com/watch?v=GekiIMh4ZkM
How many drivers does a buggy have?
One.
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.
http://www.youtube.com/watch?v=GekiIMh4ZkM
Epoxy was the plan; I have a friend with GRP experience who's offered to patch it for me. Would it be wise to add some external fibreglass sheets too? I'm not bothered about how it looks, besides, battle scars are cool
The problem is on the inside. Adding material to the outside would do nothing but add 'battle scars'. Suck the epoxy on the inside and put the battle scar material on the outside and you will have exactly what you are looking for.
Start shopping for a frame too.
Start shopping for a frame too.
- bikerjulio
- Posts: 1900
- Joined: Fri Dec 11, 2009 10:38 pm
- Location: Welland, Ontario
If you get enough epoxy on the inside, between the alloy insert and the carbon shell, all the way around, then some will bear against the uncracked inner side too, and help support the insert. It will be a lot more effective than a patch on the outside.
Regardless, it's toast.
Regardless, it's toast.
There's sometimes a buggy.
How many drivers does a buggy have?
One.
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.
http://www.youtube.com/watch?v=GekiIMh4ZkM
How many drivers does a buggy have?
One.
So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.
http://www.youtube.com/watch?v=GekiIMh4ZkM
-
- Posts: 632
- Joined: Tue Apr 05, 2011 7:41 pm
if it fails in the race and you take down a load of people as result, you ain't gonna be popular. Why risk an injury to you or others?
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