Winnershsaint
Guru
I wont bore people with details as they are posted elsewhere, but how would people view riding a CF frame/fork bike that had been involved in a 16mph front end prang?
What do you think?
- Thread starter Winnershsaint
- Start date
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OP
OP
Winnershsaint
Guru
Pranged mine. Still recovering. No visible damage, but in my head there will always be a question mark about the frame and forks even if OK. LBS have it and say they will condemn it if they are not 100% certain of its integrity and I am insured against accidental damage or loss. Bottom line is that it is a bike I loved riding. Alright it had rather lowish end 4ZA finishing kit and wheels but the frame was sub 1 kilo so kind of torn here. LBS now stocking Focus so good alternatives available if insurance pays out but more than anything I am interested to know about the kinds of potential damage I might have done. From what I recall the front wheel hit the rear tyre back bumper of a car pitching me over straight onto my shoulder. according to the Garmin I was doing 16.1 mph at the time. The computer then shows four separate bounces at around 4-5mph which I assume are the bike bouncing across the road. Basically as I was clipped in the bike somersaulted over me and bounced a few times If bike is given green light should I be concerned?
PpPete
Legendary Member
- Location
- Chandler's Ford
Does the LBS that is examining the frame have full x-ray and ultrasonic examination capabilities ?
And an undamaged frame of the same size, make, model and production batch to calibrate that equipment against?
No?
Make sure they condemn it and use the insurance to get a new one.
IMO this is a no-brainer.
And an undamaged frame of the same size, make, model and production batch to calibrate that equipment against?
No?
Make sure they condemn it and use the insurance to get a new one.
IMO this is a no-brainer.
amaferanga
Veteran
- Location
- Bolton
If there's no sign of damage then I'd ride it. I've crashed carbon bikes in races at 30mph and they've been undamaged. When you initially said a 16mph front end prang I'd assumed you meant you rode into something solid and the bike stopped abruptly. But from your description it sounds like any damage is more likely to be caused by the bike bouncing along the road and since it almost certainly would have been bouncing on components and not the frame itself then it's hard to see how the frame would have been damaged. People are ridiculously cautious with carbon frames when there really is no need IMO. Of course someone will come along now and tell me better safe than sorry and all that, but really if you thnik a carbon frame is a right off after any crash even if there's no sign of damage then best stick to steel frame and forks.
I would also ride it if there was no visible sign of damage. Jeez, if I was that paranoid, I'd have to change my race bike three or four times in a season. And if it is damaged, there's guys out there who specialize in repairing carbon frames too. Might be worth considering if you can buy it back for cheap once it has been condemned. Always handy to have a spare frame 
PpPete
Legendary Member
- Location
- Chandler's Ford
Some years ago I had a front end prang on a very good quality steel f&f. At night, in the rain. Driver offered to pay for any damage as their fault. No damage apparent so we went our separate ways. Next morning I noticed a wrinkle in the paint under the downtube just aft of the lug where it joined the head tube. Never seemed to affect the bike but I was never able to trust it in quite the same way.
As far as CF is concerned.... it's fantastic in tension and bikes are designed to use that property. A front end prang is likely (based on my exerience above) to cause a compression load. How does CF absorb the energy of compression beyond it's design limits? It often delaminates. For which there is often no external evidence.
The bike may well be OK to ride with some delamination... there will be a safety factor in the design after all. Until the next unexpected happening.
Read about Flight AA587. In short it was safe to fly even though there was, apparently, some delamination (which was not discovered until after the crash). Everything was fine until a pilot got "over-enthusiastic" with the controls.
Any damage from "bouncing down the road" is likely to be visible.... it's the possibility for hidden damage that makes me suggest to make the most of the insurance cover that the OP has in place.
OP
OP
Winnershsaint
Guru
Sorry for not making myself clearer in the OP. I was blinded by the sun and hit a parked car hard enough for me to hit the deck and fracture my shoulder in three places. the bounces were only apparent on my Garmin traces after the impact and indicate the bike was still in motion after I hit the car and I hit the deck. I think the rear wheel took the brunt of one of the bounces as it was buckled Front wheel was pringle shaped. Don't get me wrong I'm certainly happy enough to go with the frame again if I am sure it is OK, but this was a front end impact crash. My concern would be in any damage in the steerer and forks area. many thanks for youruseful insights though.
