MyE28.com

Any one on here using just upgraded front brakes and not rears? I have found as set of e34 540 front's locally for a good price , and I have brand new e28 rears at home that obviously I would like to use . This would be considered the "stage 1" brake upgrade.

Now the stock e28 weight balance is 52/48 and the brake balance is Stock E28 535i: 72.8% / 27.2%.
E32 7-series front alone: 76% / 24%
Now according to m535i.org , the "ideal" balance for a high performance 535i is 68.2 % / 31.8%
Will this be a downgrade moving the balance away from the "ideal" ratio? I know the e28 m5 used the same rear rotors as a stock e28 , so I was under the impression that rears were not that important. I have no experience in track driving or playing around with different brake setups , so if someone with more experience wants to voice their opinion that would be appreciated

My car is a 535i with a dual diaphragm E32 vacuum booster and stainless lines. Bilstein sports , m-tech red springs, moosehead control arms and poly subframe bushings. It's on 15x7's currently , but 16x8's will be in the future. All street driving , but I wouldn't mind trying autocross when the world opens up again. For what its worth , I was completely satisfied with stock brakes on california highway 9 heading to santa cruz and some of the other canyon roads I hit on the way. I just need to do brake fluid Anyway , so wondering if it would be a worth while upgrade.

You will see little/no benefit from doing the front upgrade alone, and it will actually hurt your car in autocross by making it harder to rotate under braking.

The problem with too much front brake bias is that it reduces the overall braking effectiveness of the car. A true 50:50 balance would be ideal for stopping power alone, but of course leads to rear end instability.

The E28 already has a pretty heavy front bias. By installing larger front brakes and moving the bias forward even further than stock, you will cancel out the benefits of the larger front brakes by making them work harder to stop the car, since the rear brakes will be doing less and diminishing the car's braking ability as a result.

Will it fit together and work? Yes, but I wouldn't waste your money unless you intend to do the 540i rears later.

AFAIK, a fair number of M5 guys actually upgrade the rear brakes to achieve a more neutral bias and reduce their tendency to warp front rotors.

Great input^

I did the E34 540i upgrade on the rears of my M5 which was a nice upgrade as the brakes just worked better with the improved balance. The M5 has more rear weight than 535i/528e too.

For 535i or 528e, I would suggest keeping the stock setup or a minor upgrade. At the least, do a full brake fluid flush for a nice upgrade in performance and response.

If you really need an upgrade, consider the E34 (non M5) rears. The M5/540i rears are vented but the diameters and performance are the same as the 525i and 530i. The smaller engine models had nonvented rear brakes-- which would be my suggestion for your 528e. For normal street use, the heaver the 3# heavier rotors will slow you down with really no benefit in stopping power.

From the old M535i.org document:

Front - Rear - Balance
E28 all & E24 all - E28 all & E24 all - 72.8%/27.2% (STOCK)

E34 all (except M5) - E28 all & E24 all - 76% / 24% (FRONT ONLY)

E28 all & E24 all, E34 all (except 540i/M5) - 68%/32% (REAR ONLY)

tschultz wrote:Great input^

I did the E34 540i upgrade on the rears of my M5 which was a nice upgrade as the brakes just worked better with the improved balance. The M5 has more rear weight than 535i/528e too.

For 535i or 528e, I would suggest keeping the stock setup or a minor upgrade. At the least, do a full brake fluid flush for a nice upgrade in performance and response.

If you really need an upgrade, consider the E34 (non M5) rears. The M5/540i rears are vented but the diameters and performance are the same as the 525i and 530i. The smaller engine models had nonvented rear brakes-- which would be my suggestion for your 528e. For normal street use, the heaver the 3# heavier rotors will slow you down with really no benefit in stopping power.

From the old M535i.org document:

Front - Rear - Balance
E28 all & E24 all - E28 all & E24 all - 72.8%/27.2% (STOCK)

E34 all (except M5) - E28 all & E24 all - 76% / 24% (FRONT ONLY)

E28 all & E24 all, E34 all (except 540i/M5) - 68%/32% (REAR ONLY)

Thanks but it's a decently upgraded 535, not a 528e. Maybe 540 fronts with e34 535 rears could be the ticket ?

This is the exact configuration I have on my car right now, and I think it’s a great setup.
I was going to upgrade the rears to match, but I forgot to do so last time I refreshed the brake system.

Additionally, I haven’t had any issues generating rotation with the car during AX. Bigger rears might give you more, but it’s certainly not an issue the way it is now.