What happens when you fit CF wheels...
 

http://www.southbayriders.com/forums...ad.php?t=10677
:o

:o

Sheesh!

I find those pictures a bit inconclusive, all they show is a broken wheel.

Did the wheel shatter causing the rider to bin it? Or, did the rider bin it causing the wheel to shatter?

We've all seen pics of alloy or mag wheels being bent to bugg*ry by some big offs, especially if kerbs or rumble strips are involved. I could quite see that carbon wheels don't bend but just explode under the same circumstances.

These piccies were posted by Shazzam a short while back, under a thread asking about carbon wheels and their suitability or not.

If your interested there is a reply from BST on there I beleive and it does make interesting reading.

Don't know how to link to another thread, but do a search under carbon wheels and its dated the 10/12/04 (started by Rob).

[Edited on 14-1-2005 by Harv748]

Quote from the rider behind at the time (as posted in the thread)

“I was directly behind him. His wheel exploded at 120 MPH between turn 7 and 8 at Thundehill raceway. The bike had never been dropped, dumped or crashed before. BTW, the hoop is torn in half for anyone who hasn't seen it up close in-person.” 900CR

BST's comments are more than iffy IMHO and understandably designed to fend off product litigation. When a wheel breaks up at high speed it is unlikely that the bike will come down with a bump directly upright, it's going to go all over the place.

A couple of years ago I met a senior director of Dymag at a dinner party and talked to him about the company's CF swing arm recall. He was shocked I even knew about it and claimed it was the result of overtightening of nuts and nothing to do with the CF, he then admitted that CF has 'certain properties' which make it very strong, but 'not very resistant to impact'

If the nuts are overtightened on a mag arm or wheel then they strip, and if you hit a pothole with a mag or ally wheel it bends and doesn't fall apart.

Even the main factories don't use CF in wheels at GP and WSB levels.

Perhaps the title would have been better reading "What MAY happen when you fit CF wheels..."

You can read the full thread here:

http://speedzilla.zeroforum.com/zero...d=36291&page=1


Rider/Owner’s Comments


I'm not a scientist, nor a failure analysis professional. I am, however, an experienced, advanced motorcycle enthusiast. People say that i can get around the track allright.

I will be acquiring the services of a independent third party to analyze the wheel and the crashed bike to obtain the facts.

Recently, Dunlop notified us that they would like to examine the rear slick that came off of the wheel. Apparently, the crash is gaining notoriety as each day passes.

From a customers perspective, i find it interesting that Dunlop immediately wanted to see and examine their product and contacted Nichols for permission to do so. I find it even more interesting that BST appears not to be interested in gathering the facts to determine if there was indeed an issue with their product.

I had 5,500 track miles on this bike, about 2,200 miles on the wheels, I’ve never crashed before this incident and the bike was immaculately maintained. As you can see, the bike is totaled and i was lucky to get up and walk away from this accident.

I believe that the rear wheel was to blame for this accident.

I have about 4,000 track miles on this bike at Thunder Hill race park. If you do the math, that's approximately 1,330 laps around this track which means that i've been around turns 6, 7 and 8 approximately 1,330 times without a crash.

For the record, I've never crashed my bike. I did make the error of starting my bike on the wheel stand at thunderhill one day without having the wheel stand completely inside the rear wheel stand hole and the vibration of my full race exhaust system vibrated my bike off of the wheel stand and the bike fell to the pavement.).

When I was exiting turn 7, standing up the bike and rolling on the gas, the rear end of my bike felt suddenly heavy and then sensation of a chair leg breaking, a quick, sudden "snap" to the left. The turn 6, 7, 8 combination at Thunderhill is the fastest part of the race track outside of the front straight. I estimate my speed at the time of the crash of between 115 and 120+ mph. This is a highly unusual place to fall because the bike is upright.

My rear wheel separated from my motorcycle and the Dunlop slick was separated from the wheel.

The front fork on the left side is bent outward from the impact of the cartwheeling motorcycle. The clamp that holds the fork in place is broken in half. Certainly, the front wheel took several major blows, under tremendous force, hitting head on during the cartwheeling. However, the front wheel is fine.

Finally, look at the photos of the rear wheel that is still on the bike. It appears that the spokes shredded, peeled or tore off from the inner rim and did not "snap" or break cleanly as you'd think if something took on as much blunt force trauma as the front wheel did.

I'm glad to be alive writing this email. Sam Cece

Whatever caused the crash,you've got to feel sorry for the guy!!

Just looking at the pictures tells you that the bike was fully loaded with some real trick kit!!! It must have cost him a small fortune to build the bike to that spec!!

Poor guy!!:(

For me it just confirms a few nigly thoughts I have about C/F wheels.

I hope the rider is ok and agreem withbaylissboy that it looks as if the bikes had a lot of money and TLC thrown at it.:(

Shazaam - thanks for the link to the whole thread on Speedzilla.

It makes scary reading with the statements and counter statements from some clearly vested interests.

At the end of the day we each have to make our own decisions and mine is very simple - no CF anywhere where my life might depend upon it.

Huggers, airboxes, petrol tanks (although the explosion in front of Haga when a CF tank went down the road might make that less of an option, plus a mate with a CF tank on a 996 had nothing but problems with leaks from where the pump/filter body mated with the tank), oil catchment tanks, fairings, air tubes etc all absolutely fine with me, but not wheels, frames, subframes or bars. No siree!

[Edited on 14-1-2005 by captaincardigan]