[warpaint340]

Just did F80 front rotors last night + Hawk pads. Fairly straight forward especially with the track handling brakes. Just have to replace the caliper bushings and add a spacer thanks to kern417

Now next weekend I’m going to tackle the rear rotors which I’ve heard is more complicated. Has anyone else done this yet? Any pics or videos would help

Below are the F80 front rotors on the car and also some of the hardware sent to me for the rear rotors if you’re curious

[pauli18c]

These are the standard blue 370mm M Sport calipers, with bracket/spacer and 380mm rotors? What bushings are you talking about?

What size wheels are you on? Do they clear 18s?

[casualDIYer]

Originally Posted by gabeis300

Now next weekend I’m going to tackle the rear rotors which I’ve heard is more complicated. Has anyone else done this yet? Any pics or videos would help

The rear is more complicated? I wonder how.

There are 4 connections. 2 bolts on the wheel hub, a hydraulic fluid line and, on one caliper, a wear sensor. Of course you have to switch out the rotor as well, and on some cars, the protection plate to allow it properly fit the 345 mm rotor. Additionally you may need a conversion of the rear manual brake depending on the car getting the 2 piston caliper but either than this, not sure what other elements are required. Are there any? It should be easy to figure out using realoem to compare parts. No?

[danb1979]

Thought the Blue M Sport calipers fit the F80 380mm discs fine; the caliper even states 370/380 on the rear

Are the rear discs different and don't for the Blue calipers directly?

I know the OEM BMW M3 pads are a direct fit

[warpaint340]

Originally Posted by danb1979

Thought the Blue M Sport calipers fit the F80 380mm discs fine; the caliper even states 370/380 on the rear

Are the rear discs different and don't for the Blue calipers directly?

I know the OEM BMW M3 pads are a direct fit

Well I was able to get the front rotors on no issues. Those are the 370/380 calipers, not the rears. All I had to do was replace the eccentric bushing. Each side took 20 minutes and the rotor fit perfectly. For the rear, it’s a completely different story

I wish the install was straight forward like the fronts. I tried out the rear adapters last week. You have to shave a relatively large portion of the hub to make space for one of the bolts. The wear and tear overtime might have an effect on the structural integrity of the hub overtime. The other adapters from SLG require shaving a large part of the caliper to also make space for two of the bolts. Not a fan of ruining a perfectly fine caliper either. So I sent the zimmermanns back and ended up ordering stoptech drilled rotors that almost perfectly match the pattern of the zimmermanns, but in 345x24 size which is the regular size for track handling brakes.

So even though the rear caliper can support up to 370mm, it’s not as straightforward of a process as I’d like compared to the fronts.

[warpaint340]

Originally Posted by pauli18c

These are the standard blue 370mm M Sport calipers, with bracket/spacer and 380mm rotors? What bushings are you talking about?

What size wheels are you on? Do they clear 18s?

Kern’s kit is more simple than SLG’s at least for the fronts. All I had to do was replace both eccentric bushings on the front calipers to make a little more space for the 380mm rotors. See my reply above for info for the rears

And yes they clear my 18 inch RI-A’s perfectly. I’m 18x9.5 ET27. 18 inch wheels are required for this conversion

[danb1979]

Originally Posted by gabeis300

Well I was able to get the front rotors on no issues. Those are the 370/380 calipers, not the rears. All I had to do was replace the eccentric bushing. Each side took 20 minutes and the rotor fit perfectly. For the rear, it’s a completely different story

I wish the install was straight forward like the fronts. I tried out the rear adapters last week. You have to shave a relatively large portion of the hub to make space for one of the bolts. The wear and tear overtime might have an effect on the structural integrity of the hub overtime. The other adapters from SLG require shaving a large part of the caliper to also make space for two of the bolts. Not a fan of ruining a perfectly fine caliper either. So I sent the zimmermanns back and ended up ordering stoptech drilled rotors that almost perfectly match the pattern of the zimmermanns, but in 345x24 size which is the regular size for track handling brakes.

So even though the rear caliper can support up to 370mm, it’s not as straightforward of a process as I’d like compared to the fronts.

Ah; that's a sod!

I've fitted OEM M Performance discs to my F31; stuck with OEM pads only; but the car is for every day driving, so they perform superbly and look good too

However, I know the F80 M3/M4 brake pads are supposed to be that bit better; so I may update to them in the near future

[casualDIYer]

Originally Posted by danb1979

Thought the Blue M Sport calipers fit the F80 380mm discs fine; the caliper even states 370/380 on the rear

Are the rear discs different and don't for the Blue calipers directly?

I know the OEM BMW M3 pads are a direct fit

I believe you are correct. The eccentric bushing solves the following problem:
Mount a 370mm rotor (e.g. M Performance brake kit). The caliper needs to be mounted to allow the pads to grab the entire rotor surface. Now replace that rotor with a 380mm rotor. If the caliper is fixed in place there is no way the rotor could fit. The caliper needs to be moved 10mm forward to accommodate the larger the rotor. To allow 10mm of extra space BMW would either need a new wheel hub or caliper housing, both of which need new parts. Instead, BMW used an eccentric bushing to solve that problem.

While the caliper does play a role in slowing the car, it's more the ability of the rotor to change kinetic energy into heat energy. The area of the rotor (including mounting hub) is pi x radius squared or 3.14 x 185^2 vs 3.14 x 190^2 or 107,466 vs 113,354. Given the mounting portion the rotor is the same size, the upgrade to the 380mm gives the car another, roughly, 6,000 square millimetres of rotor to soak up heat. Roughly 5% more area for the cost of two cheap eccentric bushings is a pretty clever solution.

The rear, no changes. 80% of the braking is done in the front. The trade off in cost likely wouldn't be worth the upgrade unless you were talking about a race car in which brake bias was required feature.

[casualDIYer]

Originally Posted by danb1979

Ah; that's a sod!

I've fitted OEM M Performance discs to my F31; stuck with OEM pads only; but the car is for every day driving, so they perform superbly and look good too

However, I know the F80 M3/M4 brake pads are supposed to be that bit better; so I may update to them in the near future

Interesting. Thinking I might do that as well. So parts

BMW 34218099354 (M3/M4)
BMW 34216887576 (M Performance caliper)

Are the same size and will both fit into the rear blue caliper? It's only about $40 difference where I shop.

[danb1979]

Originally Posted by casualDIYer

Interesting. Thinking I might do that as well. So parts

BMW 34218099354 (M3/M4)
BMW 34216887576 (M Performance caliper)

Are the same size and will both fit into the rear blue caliper? It's only about $40 difference where I shop.

Yes; the F80 M3 pads are the same size and measurements as the pads for the Blue 370/345mm brakes