K2 / Proflex Riders Group

General => Tech Forum => Topic started by: mooch on July 19, 2007, 09:24:23 am

Title: How bad is this crack - 4500 carbon frame swingarm
Post by: mooch on July 19, 2007, 09:24:23 am

Hi, found these cracks on a K2 Proflex 4500's easton carbon swingarm and was wondering how bad it is and how I should go about fixing it. Do I need a new swingarm or should I take it to a specialist who deals with carbon? How much would I be looking at? Thanks for any help you can give me!

(http://img300.imageshack.us/img300/2022/dsc00846oq1.th.jpg) (http://img300.imageshack.us/my.php?image=dsc00846oq1.jpg)
(http://img521.imageshack.us/img521/8200/dsc00849av6.th.jpg) (http://img521.imageshack.us/my.php?image=dsc00849av6.jpg)
(http://img521.imageshack.us/img521/4913/dsc00850ro2.th.jpg) (http://img521.imageshack.us/my.php?image=dsc00850ro2.jpg)

Pictures should work now. Will try get some better ones done for you

Title: Re: How bad is this crack - 4500 carbon frame swin
Post by: Simon on July 19, 2007, 09:32:22 am

Can't see the pic's


Simon.

Title: Re: How bad is this crack - 4500 carbon frame swin
Post by: Matno on July 19, 2007, 11:21:14 am

Hard to tell if those are pics of a "real" crack or just a surface blemish. Did you do or feel something when you found the crack or did you just happen to notice it? I've got cracks in the surface of my swingarm that look similar and have never given me any grief in a LOT of rough riding. I also have a couple of "dings" from crashes, one of which is in about that same place but about 8x9mm and about 2mm deep. Got it on one of my first rides and it's never given me any problems either... (Knock on wood).

If you can get the crack to widen or move at all by torquing on the swingarm or wheel, I'd say look seriously into getting it fixed. It appears to still be solidly bonded to the dropout, so someone ought to be able to just wrap some layers of carbon/epoxy around it. If not, I personally would probably just ride it and hope for the best. Besides, rear wheel failures are almost always less catastrophic than front wheel failures! 8)

Title: Re: How bad is this crack - 4500 carbon frame swin
Post by: mooch on July 19, 2007, 09:34:27 pm

It's on the inside of the swingarm and it was just noticed the other day. This could be an old blemish/crack or a brand new one, I don't know! We have never noticed it before though, maybe because it's in an 'out of the way' place.

It doesn't seem to flex or widen when putting strain through the swingarm. However, the rider (not myself) is scared that it is going to give way while riding and he will end up under a bus.

Any more advice please? Is this a blemish or crack? How often do replacement swingarms come up? A carbon company wants a couple of hundred quid to repair it.

Title: Re: How bad is this crack - 4500 carbon frame swin
Post by: stealib on July 20, 2007, 03:23:34 am

Hi, if you say it is not opening when flexing it, I would just seal it with some araldite resin to keep the moisture out and keep a eye on it. Scarfing a patch on it would look ugly, and you would not be able to find someone who could get the correct lay up without being a stress engineer, or have the makers drawings it would be a bodge job and they would cost the earth to do it with no guarentee. Steve(Composite expert)

Title: Re: How bad is this crack - 4500 carbon frame swin
Post by: shovelon on July 20, 2007, 08:55:38 am

I think Steve is right. If the insert is not loose, the crack just may be a blemish.

A little araldtite or whatever sounds like a plan.

Terry(going to have a look at mine)

Title: Re: How bad is this crack - 4500 carbon frame swin
Post by: Thunderchild on July 31, 2007, 06:21:55 am

Have you noticed any new creaks or other frame noises?  Good chance they are just surface blems.  

Thunderchild