Last time I were out on the track I lost a brake disc as can be seen on the picture.
Is there anyone who knows how this can happen? It was nearly new, had only been used two or three hours.

if your bone or cvd fell out i guese it would be possible but thats not likely are you sure when you were rebuilding the car or something it didn't fall out or something. other whys i can't see how it would happen

It was there at the start of the day and the braking worked fine. But before I noticed that it was gone without a trace, the braking got worse which is rather obvious! But aside from that there was no problems with the drivetrain or the buggy as such! No one at the track had any suggestions, but I was sure that there would be someone on this forum that had the answer.

by looking at you picture the rear brake is a compostie brake pad, not metal. if thats the case you could have worn or damage it causing it to fly apart. The picture also show a bunch of little specs all over the chassis which could be whats left.
or a rock could have jamed in there causeing it to break, happns

Yea most likely it fell apart and the tens of thousands of RPMS of the bones took care of the rest.

I'd say all that orangy dust around your chassis is the missing disk. Thats the problem when you have a dinner plate for a rotor.

Good to have you back Grahama!

What do you mean with "dinner plate for a rotor"?

What kind of material is best for brake discs?

Dinner plate = Ceramic

I find cold hard steel is best.

some sort of alloy or craddocks

Thank you all for the suggestions and helkp, but I have another question that shows how new I am to this:

What is craddock?

Now thats new.

It's a brand of composite material brake disks.

I have been looking around for ya and I'm gonna make a list of my fave brake sets for ya in link form:

[link=http://crazynutracing.com/product_info.php?cPath=51&products_id=247]Crazy nut Brakes.[/link]

making up for lost time I see

that was added the same day that,,we lets say, the same day a few guys were not playing nicely

One reason it may have disintegrated is it may have been on there too loose
If it's starts wearing down you need to readjust the plates to keep it from developing a wobble
once it wobbles it can start just breaking apart

That's Classic. Had Enough.........................?

Well the problem you had was actually quite a commom one. The cause of it is that often the pad screws are tightened unevenly. As the disk spins, it grinds away at the edge of the disk, it becomes inbalanced and starts to wobble. Evenually it cracks and it's off to Coventry. Oh well back to the LHS for more.

grahama89's got my back,,,,gotta love it

grahama89,
Did you use that CrazyNut set up on one of you Hypers?
if so did it clear the stock flywheel? purple flywheel?

Please resist the urge to curse, flame, degrade, insult or embarrass someone in your post......
Did everyone get this or just those of us that deserved it?

Right, No I haven't used it. But I know someone who has and they swear by it. I would imagine that it would clear both flywheels as it's a single disk at each end but as this is for a different buggy I dont see the point of your dig. My point is that ceramic disks are good at lessening the effects of brake fade, but the are more fragile which is why I suggest metal disks and normal pads. My advice doesn't have to be taken at the poor soul could simply fit another stock disk and run the risk of a repeat performance.

I wondered the same thing for a while,
,,then I said to myself "Quite being paranoid dummy"
then I said to myself "They're coming to take me away HAHA
They're coming to take me away HOHO HEHE HAHA"

Hey man, just because you're paranoid doesn't mean they are NOT after you!!

To the funny place
where life is beautiful all the time...

Alex,,,You know you're stuck with that handle now LOL
If you want any So Cal Bling,,, just let me know I'll hook you up

Cheers but I can get things for nowt now. The benefits of testing products.

BTW............ HERE THEY COME ..............

Both brakes on my stupid Ultra are gone, for the past 9 monthes[:@]