Carbon wheels are totally not worth the risk. I’ve seen so many shit themselves. There’s a good reason why they’re not generally used in racing. they’re not even lighter due to the heavy hubs than a mag rim.
Racing also x Ray their carbon fibre regularly. it’s not used in series really outside of GP. For anything structural
One thing really interested me in the pictures, apart from the massive and obvious failure, and that was the outer edge of the supposedly undamaged part of the rim which appears to be raw and only partially consolidated CF, short on resin, with voids and an unfinished surface. Is that really how new BST wheels are finished? I honestly can’t believe that it is - if it is, I think leaving them out in a slight frost would pull them apart as any moisture there would expand and delaminate the rims, making them entirely unusable on the road. If it isn’t how they are new, and these were damaged by a PO (looks like they did a quick lap to see how they felt before fitting tyres ) or possibly they were scuffed up to intentionally mask previous damage, then that person is playing fast and loose with the life expectancy of all subsequent owners…. Not good. Maybe a third option if BST are as good a quality as their price and reputation implies, is that these are fakes. I guess it isn’t too far fetched- if counterfeiters can make knock-off very high end road bike frames that need close inspection to spot, wheels would not be that difficult. It doesn’t excuse them continuing to be sold as usable, but might better explain the failure and what the picture shows.
BST's are not finished like that. The finish on the one's I had were, in my opinion, as near perfection as they could be, and no areas were thin on resin or lacquer. Mine were 6 or 7 years old when I sold them and still perfect.
Carbon is all pre preg. Has been for many years. The cloth has the right amount of resin already in it and is activated by vacuum and heat in the autoclave. You can't ever not have enough resin. The carbon which looks perfectly lacquered is exactly that. Lacquered! The perfect finish adds nothing to the structural strength and is purely cosmetic. The problem with carbon rims is that they are incredibly stiff. Carbon allows for some elastic deformation but no plastic deformation. As a result, they break rather than dent or buckle.
There are still a few suppliers of carbon cloth out there. I have some 100g/m2 2x2 twill tucked up for some future project. That came from a friend who worked at Lola racing before they went bust, my last lot came from a supplier near Swadlincote about 3 years back. It’s niche compared to prepreg now but still a few places doing wet lay but mostly for non structural stuff or very low production run as far as I know.
Dry carbon which is then impregnated with resin (wet layup) is still used for repairs to Boeing and Airbus aircraft. Used to repair non primary structure such as fairing panels.
That looks more like the wheel was rotating as it hit something causing a scuff than lack of resin to me
@J0n3s those wheels have had one heck of an impact! No way could you not have noticed that, particularly riding the bike when it happened, you would have crapped yourself at the impact! This video below shows BMW testing the TK wheels on the S1000rr , jumping a kerb and the rim is still intact- https://youtu.be/Gwb7ZDfwWqA?si=JGo4HFUnEFCBxlKg Regarding the finish on BST wheels, I bought a set in June 2021 for my 899 and they have been superb, I check them every ride as I wash the bike and apart from a few tiny stone chips they are still perfect.. I should add that both my pushbikes have CF wheels and the cross section of these are tiny compared to the motorbike ones, the MTB in particular has taken years of abuse hitting/jumping rocks etc and the only trouble I’ve had is a couple of broken spokes in the back wheel . The main trouble with your wheels is that you don’t know where they came from ( genuine BSTs or not ? ) and you don’t know what abuse they have suffered in the past.
I was forced to go into this, For the guys saying they used them for X years and no problem, the problem is when they go its without warning, if you have an internal crack it can’t be seen, only Xrays can and who does that. I have a problem with my SL swing arm, went down on it and there is a crack, I put a new arm on because not many said they could repair it and I spoke with Expert people and those who were not looking for money out of it said, can you trust your life with it? as if and when it goes it will be at the very worse time. So I have a very expensive coffee table piece if anyone wants to buy it! For the road its OK, But not for the track, Wheels, I have them on my SL and they are great but there is not much difference between them and my OZ Gass wheels.
