435d brake query

[Capt Bravz]

As per the title I own a 435d. It's the Msport version so has the upgraded 'blue calliper' 370mm discs.
At the last service the mechanic advised that the front brakes were worn and would benefit from being changed in the next 3000 miles or so. Rather than just fit replacement OE discs and pads I've been looking around for what is available as an after market/upgrade option.

There are lots of dimpled and grooved type packages on Ebay and my Googling has found numerous threads on other forums by people who have enquired about fitting M4 380mm front discs. This has routinely been negated as not a simple P&P due to slightly different spindles on the struts.

However the REAR discs for M4's (and 2's and 3's) are listed as being 370mm- Is it the case that I can fit the rear discs from an M car to the front of mine (diameters being the same) and therefore benefit from spangley drilled goodness and slightly less unsprung weight?

Anyone with more technical knowledge than me who can advise would be greatly appreciated.

[helix402]

Quick answer, no.

[Capt Bravz]

helix402 said:

Quick answer, no.

And the slightly longer answer with technical reasoning?

[drdino]

You can get the dimpled M-performance discs (370mm Φ) which were fitted when the gold-caliper pack was bought.

[helix402]

Capt Bravz said:

And the slightly longer answer with technical reasoning?

Rear discs have space for handbrake shoes.

[Capt Bravz]

helix402 said:

Capt Bravz said:

And the slightly longer answer with technical reasoning?

Rear discs have space for handbrake shoes.

Perfect- thought there would be a reason why- that's cleared that up then- many thanks

[Pica-Pica]

helix402 said:

Capt Bravz said:

And the slightly longer answer with technical reasoning?

Rear discs have space for handbrake shoes.

I am really very surprised anyone had to be told that!

[Capt Bravz]

Pica-Pica said:

I am really very surprised anyone had to be told that!

You are? Ah well in that case you can bask in your superior knowledge of brake disc specifications. I asked a question and was provided with the answer and reasoning I required. Many thanks for your input.

[Pica-Pica]

Capt Bravz said:

Pica-Pica said:

I am really very surprised anyone had to be told that!

You are? Ah well in that case you can bask in your superior knowledge of brake disc specifications. I asked a question and was provided with the answer and reasoning I required. Many thanks for your input.

Apologies. Front and rear brakes are mounted considerably differently on all cars and as such would be different. Also rear brake discs on many BMWs have drum-in-hat rear discs (a brake disc with a drum inside that takes the parking brake shoes). That would certainly be the case with a manual parking brake lever.