Z4 coupe - track day brake judder

G

gurkin1234

Member
Hi everyone - hoping the forum masses can assist!

Just took my coupe on its first track day at Brands Hatch and was getting quite significant brake judder after a few laps - to the point where it was shaking the car around and felt almost unsafe to continue. When the brakes were cold it was fine.

I was extra careful to avoid overheating the brakes by doing short stints, not leaving the handbrake on in the pits and doing a cool down lap before coming back in.

Any ideas what could have caused this and what the solution may be? Thinking back I've noticed it before if braking down from high speeds on the road - eg a motorway off slip to traffic lights - but never anything like I experienced today.

Any tips welcome - Oh and a picture from the track day!
 
Are you running standard pads? If so it’s probably just pad transfer from the soft road pads, and the wet conditions will have meant you’d be braking harder for longer.

Sometimes you just have to drive through it and clean them up - especially if it has lots of road miles since the pads/discs were replaced, although you can take the wheels off and clean up the disc with a wire brush.

It could also come about from braking method. Did you get any instruction? Do you stay on the brakes right until the last minute, pressing harder & harder to slow down?

A combination of better pads and braking hard & fast (biggest cooling effect due to the high speed) then easing off to settle the car before turning in - and cooling the brakes even further - will all help.
 
Good advice m5, but if he's saying it's nearly unsafe to contine, I'd be betting it's something more than pad transfer.. which should be gone after the first lap or 3. (If your using the brakes and not doing a few senic laps) I'd need more info, like is it doing it front and back? Or just the front? Which side? Or both?

Possibly warped rotor, but then it would also be doing it when cold, although the harder you brake the more predominant it would become.

Anyways, all good advise given by m5, and glad you got out there to have a blast. I have to warn you mate, carefull, that track bug can bite hard...
 
Thanks both for your replies.

I think part of the issue may be the hour that I went out before getting tuition where I was braking as you would on the road - squeezing gently and then increasing pressure until slowing down enough. Understand now that track braking is different!

Juddering definitely in the front wheels - instructor thought either significant pad transfer or warped discs.

Juddering was worst when slowing for the faster corner entries - paddock and druids mainly - the ones with most brake pressure applied.

Nezt steps I think is to get the car into the shop over the new year and get the discs and hubs inspected to make sure they're not warped and then take it from there. Thanks again.

Plus you're right - can't wait to get back out there again!
 
Check your tyres are balanced spot on. I had one that felt fine driving around, no judder at all. But when I braked hard frm high speed I would get some brake judder. I replaced a set of discs and pads several hundred squids only for it to resurface. Finally I got my wheel Ballance checked and one was not quite perfect. Could have saved my self a whole heap of money. :(
 
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