[Andy198712]

Hi,

odd question,

ive got a 2010 LCI E91 325d SE so 3.0 N57 Auto...

want to buy new REAR discs and fancy the drilled zimmermans (yh partly for looks tbh)

how do i know what size discs i have? shy of taking the wheel off and then the rear disc which isnt an easy job given they are normally stuck on and take alot of hammering to get off.... not something i would do on a disc i was refitting and i don't own a disc puller

can anyone tell me what i should have? or a smart way of measuring them? would need a bigger set of callipers then i have....

i don't mind popping the wheel off if i need to but if i don't have to it will save alot of faff and travel on my part as i live on a slope, and don't like working i the street.

cheers
Andy

[dragerboy]

I would guess you have the same as my 330d E90 Pre-Lci

So that would be 336mm If I can remember. They probably look slightly bigger than the fronts?

[Dann]

Look up the part number for them on real OEM using your VIN.
Pretty sure they have the size against the part number on there

[bishbosh]

Not a major drag to remove and refit brake discs tbh. Bash the backside with a rubber mallet and the disc will come off. Don't really need a disc puller.

[matt_s]

Put two sticks resting on either side of the disc, through the wheel... measure distance between...

No wheels were removed in the writing of this comment... 😀

[rasa bmw]

get a piece of string and wrap it around the disc,,then measure the string.or a tape measure(cotton type)

[Andy198712]

Originally Posted by rasa bmw

get a piece of string and wrap it around the disc,,then measure the string.or a tape measure(cotton type)

Now that’s a clever one!!


Yeah I do feel rears are bigger then fronts but that can’t be surely?! I notice it when washing the wheel barrel.

The last e91 rear brakes I removed took some serious welly, I guess I’m being a bit lazy too tbh!

I’ll double check real OEM too

Thanks guys

[matt_s]

Originally Posted by rasa bmw

get a piece of string and wrap it around the disc,,then measure the string.or a tape measure(cotton type)

That would of course give you the circumference... divide by 3.14 to give you the diameter...

[bfleming]

The fronts will be 330mm diameter, 24mm thick
The rears will be 336mm diamater, 22mm thick

So you're right in saying the rears are larger.

For removal, make sure the handbrake is off. You may also need to release the handbrake shoes a little (inspection hole & the cog you need to turn with a screwdriver). I have never seen a rear BMW disc refuse to come off - but I have seen people spend hours hammering everything in sight as the handbrake shoes are still binding.

[Andy198712]

Originally Posted by bfleming

The fronts will be 330mm diameter, 24mm thick
The rears will be 336mm diamater, 22mm thick

So you're right in saying the rears are larger.

For removal, make sure the handbrake is off. You may also need to release the handbrake shoes a little (inspection hole & the cog you need to turn with a screwdriver). I have never seen a rear BMW disc refuse to come off - but I have seen people spend hours hammering everything in sight as the handbrake shoes are still binding.

ideal thank you