Roadster s brakes?

[Spud]

I'm looking to replace the front discs on my e85 roadster s as I've got a slight juddering through the steering wheel when I brake.

ECP are listing my car as having 300mm front discs but I've measured mine and they are 325mm. Are mine standard and ECP have got it wrong or have mine been upgraded?

If they are standard then what other model BMW's use them as searching for Alpina parts doesn't offer up many options. E46 330i/330D looks like it might be a match for 325mm discs.

[Charles]

Can't help with disc sizes and part numbers but you might also want to check suspension bushes whilst under the car - particularly the rear trailing arm (or "brake reaction") bush, as this can result in brake judder when getting worn.

[Spud]

Can't help with disc sizes and part numbers but you might also want to check suspension bushes whilst under the car - particularly the rear trailing arm (or "brake reaction") bush, as this can result in brake judder when getting worn.

Cheers. I'll do that.

[PerryGunn]

Due to Alpina cherry-picking from the BMW parts bin the front setup uses Z4M/E46 M3 pads on a Z4 3.0Si disc (also used on most of the E46 330 variants) - I know the Alpina predates the 3.0Si & Z4M but so do the BMW parts

The front discs are 325mm and OEM part # 1 166 071
The front pads are ATE part # 13.0460-7185.2

Rear discs and pads are the same as the pre-facelift 3.0 Z4 so don't require any special consideration

[ade and liz flint]

I've got a slight juddering through the steering wheel when I brake.

Finding the cause of the judder is primary concern and is normally caused by brake pads being immobile or having restricted movement inside the calipers. This then causes the pads to rub against the high spots on the disc(s) as they rotate and the disc warps and causes the vibration you feel when the pad touches the disc under force as the high spot expands further and makes the wheel shake. Replacing discs and pads may not cure this unless the calipers and sliding pins are cleaned thoroughly and the new pads mounted correctly with a few dabs of copper grease in 'just the right places'. If you just have new pads put into grimy calipers and on dirty sliding pins, you'd be wasting time and money.

My money is you'll find nothing wrong with your brake reaction bushes.

Perry's part assessment is correct. I wonder where he found that information The front brake pads are Z4M and late E46 M3 parts, front discs are from the E85 3.0Si

[PerryGunn]

Perry's part assessment is correct. I wonder where he found that information

A long while back, some bugger in Wales took the time to drop me an email during a break between sheep-worrying sessions...

[Spud]

Thanks very much for the help guys. Much appreciated.

[ade and liz flint]

Perry's part assessment is correct. I wonder where he found that information

A long while back, some bugger in Wales took the time to drop me an email during a break between sheep-worrying sessions...