Racin Brake BBK and Caliper upgrade 135i

[DavidV]

When I brought my car for the winter tire change the shop made a mistake by not removing the hub ring that came off my Forgestar F14 wheel, and putting on my original wheel, and thus pressing the hubring into the brakedisk gap.
The only way to get the ring out undamaged was to disassembe the disk, and thus also removing the caliper.
When we did that, it showed some remarkable wear on the brake pads, and also it showed that the dust seals of the cups were burnt.
Further examination revealed all calipers had burnt cupseals.
And that the brake pads were all shot. They were OEM brake pads that had gone thrue 5000 miles and 2 thackdays, last one being Spa Francorchamps, and they really had not survived that last one.

I have had terrible squeeking from the left side brakes for some monyhs now, so I had a pair of Stoptech pads already at home as replacements.
I went home to get them, so I at least make it thrue winter while I considdered my options.

I really didn't want to spend €5500,- on a new BBK for the tracktime my car sees, but something had to be done.
After some research I found Racing Brake recently made an option available especially tailorred for the 135i
So I ordered a kit.

These are oversized slotted and ventilated disks, 350x28mm instead of the 335x26mm originals.
The cups are full stainless steel, beautifully made precision cups with cooling contact patches to reduce heat transfer from the pads to the cups.
Racing Brake advises to remove the plate which is behind the brake pads to reduce noise and heat capacity.

I didn't order a full set of seals (pressure and dustseals) from Racing Brake because the BMW dealer stated they could supply me with those.
No need to have them come overseas, I thought.
Wrong.
BMW only supplies the dust seals and NOT the pressure seals for the M-spec brakeset.
So I had to backorder them.
Fortunately RacingBrake had a group discount of 15% for all of these components, so the only downside to this was the extended wait.

In fact it took so long that when I had all the components here it was the beginning of Feb.
The shop didn't have the right mechanic available to asist me (a former racing pit crew mechanic who is very knowledgable and part timer there) so it was installed only last friday.

If you look closely you'll see the burnt dust seals.
It was not as severe as the some of the pics I had seen online, but this already is bad enough...
We also decided there and then to modify the dust shield so it lets the brake disks get more air fro the ducts, while preserving the heat shield to the lower arm rubbers.

As you can see, it fits perfectly


There is a bracket supplied to get the caliper out 8mm more so the disk fits. I replaced the Stoptech brake pads with the recommended ET500 pads from Racing Brake. I was quite pleased with the Stoptech pads. No dust, and reasonable performance. They lack the initial bite the OEM pads have, though. But for a winter set good enough.

Then it was time for the rear calipers.
Unfortunately there is no rear disks option available yet from Racing Brake.
(They are waiting for a subscription for (at the moment) 7 more interrested people to manufacture them.
You can get the whole package, or parts, for a 20% discount...)
So just the caliper upgrade then.

After this I went to do the initial brake in procedure, which did some good, but I think these brakes need at least another 1000km to realy come to life.

I stored my old performance brake set in the attic. I think when I will do the summer/winter tire change I will put the OEM performance set on for winter. No need for a BBK when there is snow and ice...
I can ot wait for Racing Brake to have a rear wheel BBK set available This really looks the business.
When the weather clears I'll make pics of the car. For now... this morning it had snowed again

[DavidV]

Ah forgot to mention.
Despite of the larger size, thes 2-piece floating disks are lighter than the OEM brake disks.
Actual weight for the 350x28 is 18.9 lbs. , weight savings of about 2.3 lbs. per wheel when compared to OEM disks.

Still getting used to the clinging sound when driving over small ridges. These floating disks realy do move a bit I guess

[Sticky]

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