Brake disc thickness

Greg · 19 May 2014 at 16:16

Guys,

I've scoured the internet to end up fruitless but I'm looking for the minimum brake disc thickness for a BMW Z4 Coupe (E86), front and back. Its going in for a Pad change and I'm concerned that I should get the discs done at the same time.

Hope you guys can help?!

Regards,

Greg

ryanpetit · 19 May 2014 at 16:17

Have you looked on eurocarparts? I found mine on there whilst sourcing a replacement.

rodenal · 19 May 2014 at 16:19

You can normally tell by the lip, unless you've had them skimmed in the past?

If there isn't one, I wouldn't worry

snitcher · 19 May 2014 at 16:25

definetely change both else you might find them squaling whenever you brake.

abbotsmike · 19 May 2014 at 16:28

Always doing pads and discs at the same time is something that garages do to rustle up extra money. I've never found it necessary. Pad squealing is more down to vibration in my experience.

rodenal · 19 May 2014 at 16:31

Doing one disc makes no sense - if one side is worn enough to need replaced the other won't be far behind unless you've been running for thousands of miles with a dud caliper.

Especially given the price of them on most cars. Discs for the Z4 certainly aren't expensive

Minstadave · 19 May 2014 at 17:43

snitcher said:
definetely change both else you might find them squaling whenever you brake.

Nonsense.

abbotsmike · 19 May 2014 at 17:46

I read it as do pads and discs at the same time (possibly misread). This is unnecessary. Always change discs in pairs though.

Minstadave · 19 May 2014 at 17:52

abbotsmike said:
I read it as do pads and discs at the same time (possibly misread). This is unnecessary. Always change discs in pairs though.

Yup I agree with you.

Dandle · 19 May 2014 at 21:01

It is stamped on the disk somewhere on my 530d E61 it was 21.5mm (if I remember rightly) which the disks were under before the first pad change was due.

Greg · 19 May 2014 at 23:27

Thanks guys for all the replies. MeSured them today and they're just over 23mm

Where on the disk are they stamped?

Sindri · 20 May 2014 at 00:10

Greg said:
Thanks guys for all the replies. MeSured them today and they're just over 23mm

Where on the disk are they stamped?

If you put your reg in Eurocarparts, then select one of the brake disc options under the product description it usually lists the minimum thickness.

Greg · 20 May 2014 at 10:53

Ok, 23mm is the minimum thickness and they're now on a smidgin over 23mm. Does this mean they should be changed, or is that the minimum with new pads on?

I'm thinking that they should be changed to be on the safe side?

Thanks

abbotsmike · 20 May 2014 at 10:55

23mm is the minimum thickness of the disk. It has nothing to do with the pads. Assuming you've measured accurately, then I'd probably get them changed as it's going for work on the brakes anyway. It's only an extra 10 minutes per side (if that) to whip the disk off.

Matt82 · 20 May 2014 at 11:03

If the disc was 24mm but heavily scored or corroded, i wouldnt use them again

Greg · 20 May 2014 at 11:05

thanks for the help guys, I'm going to do the whole lot seen as they're on the minimum!

I knew OcUK could help!

thanks