Carbon frame damage

SteveR_100Milers

Today had a disaster potentially - bike fell onto a rock with trrhe top tube impacting against it which scratched it (not happy but not life threatening) but also cracked the surface of the acrylic in two places. There are some very small (3-4mm) radial cracks around the site of the impacts, there doesnt feel as if its caused a "dent" in the tube wall, but it doesnt look good. However, the frame feels as solid as it has always, I rode it 25 miles how as I had no choice, and for the last 10 miles I rode it as hard as I would normally (but not a full on max out of the saddle effort). Being CF and relatively brittle I am worried about catastrophic failure and the mess that might make.......

Anyone else done this, or similar, and what was the outcome?

Im taking it to the LBS now, so will get their opinion too.

gkerr4

Being CF and relatively brittle I am worried about catastrophic failure and the mess that might make.......

this is just hype put about by 'steel-lovers' IMO

have you ever cut a carbon steerer on your forks? - I have, twice in fact and if you haven't cut one, PM me your address and I will send you one of the cut-off pieces so you can try and destroy it - let me know how you get on!

it's bloody tuff stuff!

it'll put your mind at ease about the frame anyway!

try not to worry about it - i know it's easier said than done, but your damage is almost certainly limited to cosmetic

redddraggon

gkerr4 wrote:

Being CF and relatively brittle I am worried about catastrophic failure and the mess that might make.......

this is just hype put about by 'steel-lovers' IMO

I'm not a 'steel-lover', but carbon fibre is 'relatively brittle', it doesn't really have any high energy failure mechanisms like ductile flow in metals, it only has low energy failure mechanisms, and will fail without much prior deformation. Force needed to initiate a crack in the carbon fibre is pretty high though.

I'm sure the frame is fine, it's probably just the laquer.

Tom Butcher

Would you risk it though? Personally I'd be getting it checked out by an expert if at all possible. In the meantime maybe mark the ends of the cracks with a piece of tape that way at least you'll know if they are getting any bigger.

aracer

Tom Butcher wrote:

Would you risk it though?

Yes. I put a dent in the TT of a carbon MTB where the tube was actually squishy and the fibres obviously broken - but only for part of the tube diameter. However there was no obvious loss of stiffness in the actual tube. I continued riding the frame for over 6 months, simply monitoring the dent to see if it was spreading or the tube losing its stiffness - couldn't tell there was any change at all. Eventually retired it after another crash which damaged it more along with some other bits and put an insurance claim in for the lot.

The point is that if it's not already catastrophically failed it's probably not about to catastrophically fail, as damage doesn't propagate in CF like that. I very much doubt you've damaged the carbon at all, but if you have and there is no noticeable loss of stiffness in the tube then I'd suggest you haven't got a problem.

SteveR_100Milers

I took it to one of the LBS's whom I know quite well.

They didnt think it had gone through the lacquer down to the fibres, which was my view too, but the critical word is *think*. Therefore its down to how much risk I want to take, and the simple answer is not much (and not just for my own sake).

The one guy would carry on riding it, the other wasn't so sure. Suggested I might contact Mike Burrows (of Lotus fame) maybe he has an opinion. Tom I have already marked the crack ends after it happened, and they havent got any bigger (yet). I am so pssd off its untrue, I cant afford to replace it, and if I dont ride it then thats me off the bike for at least 18 months, which frankly might as well be for a lifetime. I certainly wont race/sportive with it so goodbye to competitive cycling.

gkerr4

post a picture of it - can we see the damage?

SteveR_100Milers

ok how do you paste a pic to the forum (without uploading somewhere else via a hyperlink)???

meagain

"I am so pssd off its untrue, I cant afford to replace it, and if I dont ride it then thats me off the bike for at least 18 months, which frankly might as well be for a lifetime. I certainly wont race/sportive with it so goodbye to competitive cycling."

Pretty awful I'll grant, but you have all the bits except a bare frame, so surely there must be something you can get 2nd hand that will still be worth riding, even if not quite so "competive" as the CF one?

SteveR_100Milers

Here it is, except I cant seem to get the actual picture to display..... :roll:



Yeah I guess I *could* trundle round on my winter bike, but thats fine for that type of riding. The Focus with T bars was about as basic as you can go for TTing, and I was planning to get a TT bike for next season...not any more.

I havent seen many half decent CF frames kicking around on ebay (other than potentially accident damaged ones like mine!)

redddraggon

Doesn't look too bad to me.

aracer

Doesn't look at all bad to me - you've not broken any fibres, just damaged the top resin coat (and that doesn't do anything structural). I'd not only be happy to ride that, I'm even happy to recommend to somebody else that it's OK to ride.

SteveR_100Milers

It's not obviously broken, but is it a risk worth taking? There is another similar *dent* about 3" further along the tube, plus lots of scratches....these are purely cosmetic.

To be honest, I'm hoping that someone has done something similar, and they are going to tell me that they have ridden the bike since for several thousand mikes without any problem......

By the way how did you get the pic to show? I followed the inctructions in the sticky:

I assumed its simply copying the url and pasting it...obviously not

redddraggon

img]http://s305.photobucket.com/albums/nn211/stever_008/?action=view&current=framedamage-2.jpg&t=1210085121963[/img]

You need to get rid of the bold bit, the img tags need a link with an image file extension.

gkerr4

doesn't look too bad and surely a risk worth taking. (and barely a 'risk')

also bear in mind that the nice structured fibre weave you can see is purely decorative. so even if you go through the lacquer, you still have this top layer of non-structural material to content with and them the proper carbon under that.

seriously - i'll send you a piece of fork steerer i cut off recently - it is rock solid - if the bike fell on it's own weight onto the rock - i mean, no-one kicked it over or was standing on it at the time - then it will not have damaged the frame.

SteveR_100Milers

Thanks guys, feel a lot happier now I really ought to know this since I studied materials at uni years ago....classroom theory is one thing, practical experience another!

meagain

"half decent CF frames"

Ah, I didn't appreciate HAS to be CF.

andy_wrx

Last year, I propped my Roubaix against the sign at the top of Ventoux, looked round for someone to ask to photograph me.

It was a seriously windy day and a gust caught the bike, then almost in slo-mo but before I could do anything it clattered down the sign and the stones it's concreted-into.
- Terrific !

It's scraped/cracked the lacquer off the seatstay in half-a-dozen places, in a similar way to your bike, once for each bounce no doubt.

I've carried on riding it and it hasn't failed on me yet. It's my Summer bike, does sportives, fast riding when the weather's up to fast riding - 48mph in the Peak District on Saturday, on a road so bumpy I was having trouble seeing where I was going...

I'd rather a seatstay didn't break at that sort of speed, but I reckon it's OK, although I do have a check every time I wash it (well, I check-over the whole frame, as I do the Winter alu bike - but I specifically check these scrapes).

One day I'll beg some clear nail varnish from Mrs wrx and just touch it up - it's not that obvious unless you know it's there, but as I do know it's there I see it every time I look at the bike !

SteveR_100Milers

Thanks Andy. I got similar advice at the club 10 this evening, but suggestion is to cover the cracks with lacquer (which you can get easily from halfords) to prevent moisture ingress, which I seem to recall could cause delamination? Doesnt seem to have affected your bike though so perhaps not that critical.

oldwelshman

If it has put up with your ass on it for last few months I am sure a bit of Rhigos rock wont damage it any more
meagin, just insure your bike now and claim in about 3 months or even better find a pothole close to you ( should not be too difficult) take a pic and send it to local council and tell them it made you crash your bike

aracer

SteveR_100Milers wrote:

To be honest, I'm hoping that someone has done something similar, and they are going to tell me that they have ridden the bike since for several thousand mikes without any problem......

Well I did mention earlier how I did something much worse to a carbon frame and rode it for at least another 6 months off-road without any issues. I don't think I'd even consider replacing that if I had enough money that I wouldn't notice the cost of a new frame.

aarw

@ GKERR

the steerer tube will be considerably stroger than a top tube or a down tube. it neecds to be.

gkerr4

you think?

I'm not so sure - i'd have thought the wall thickness might have been pretty similar no?

besides, I wasn't comparing strength as such - just trying to demonstrate (and allow Steve to feel for himself) that CF components arent the fragile things we seem to try and convince ourselves that they are!

aarw

depends on the bike i guess but i can't imagine the walls of the top or down tubes being anywhere near as thick as the steerer.

if i press my downtube at the side with my thumb, i can feel it flex, yet it's a stiff frame. couldn't do that if it was close to the thickness of the steerer tube.

gkerr4

mine don't flex - they are rock solid - even the widest part of the downtube which is as wide as the bottom bracket area!

the steerer tube is the same wall thickness as the seatpost - both branded as 'S-Works' items - i just figured that the main tubes would be similar.

maybe not though..

SteveR_100Milers

gkerr4 wrote:

you think?

I'm not so sure - i'd have thought the wall thickness might have been pretty similar no?

besides, I wasn't comparing strength as such - just trying to demonstrate (and allow Steve to feel for himself) that CF components arent the fragile things we seem to try and convince ourselves that they are!

Indeed, though of course it's not fragile if its fabricated in the right way, otherwise Airbus would have long since folded. The question is whether there is a similar design strength and operational safety margin in the design of a bike frame as there is in the horizontal stabilizer of an A320.