# Upgrading 528i brakes to 540i



## McMannusBMW (May 29, 2004)

From what I've read on the forum, upgrading my 528i's brakes will add about 14 lbs a wheel, all in all, 56 lbs of rotational mass. I want to get these bigger brakes, but am worried about the effect it has on the car's acceleration and torque. 

Those of you who have upgraded from the smaller 528i brake calipers and rotors to the 540i's, does the additional 56 pounds reduce the acceleration of the car significantly?


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## transporter528 (Oct 8, 2004)

14lbs?? that doesn't sound right, were did you read that?


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## Moolji (Jun 25, 2003)

transporter528 said:


> 14lbs?? that doesn't sound right, were did you read that?


http://www.bimmerfest.com/forums/showthread.php?t=60496
:dunno:


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## McMannusBMW (May 29, 2004)

yea, that's the thread moojli. it should've been 14 lbs/ front wheel, i don't know about the weight gain at the rear wheels. have either of you put the 540i's brakes on your 528is?


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## 528i (May 1, 2004)

The 528i and 540i rear rotors are the same.


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## DZeckhausen (Mar 11, 2003)

McMannusBMW said:


> From what I've read on the forum, upgrading my 528i's brakes will add about 14 lbs a wheel, all in all, 56 lbs of rotational mass. I want to get these bigger brakes, but am worried about the effect it has on the car's acceleration and torque. ?


It's not even close to 56 pounds of rotational mass. The 540i rotors are about 6.8 pounds heavier each than the 528i rotors. So you're increasing rotational mass by 6.8 pounds per FRONT wheel. The 528i and 540i share the same rear brakes, so there's no change there.

The 528i front calipers are aluminum, while the 540i front calipers are iron. So the 540i calipers weigh about 7 pounds more per front corner. That's additional unsprung weight but it is not rotational.

I have done a few of these conversions and have helped others find the parts. Haven't heard any complaints about effect on handling or acceleration. I have heard a complaint from someone who installed M5 brakes on a 528i though.


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## jensenh (Jul 29, 2003)

dave, could you possibly help me find some 540 front brakes? or could you recommend a rotor and pad set that would fit my needs. and i don't want to fork over the money for a bbk. my needs: daily driven, weekend driven hard on canyon carving, etc. autocrossing here and there. track time possibly once a year. and i guess i hate dust too, but thats a secondary concern


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## mottati (Apr 15, 2003)

I put 540 brakes on my 528. It is a simple remove and reinstall procedure. You should be able to find used parts. You need the obvious, calipers and rotors and pads, and the less obvious, carriers (cailper brackets) and the 'anti rattle clips'. I bought everything new from the dealer for about $800. Not too much more than doing a standard brake job. You need to match the production dates for the rotors and carriers, as they changed the offset around 3/00 iirc. I just bought parts that matched my car's production date, to make it easy to remember. No noticable degredation in performance or handling, and the brakes were a lot better on the track. Additionally, you can get track pads for the 540 brakes, i don't think they exist for 528 calipers.
Mike


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## m5next (Oct 9, 2003)

DZeckhausen said:


> It's not even close to 56 pounds of rotational mass. The 540i rotors are about 6.8 pounds heavier each than the 528i rotors. So you're increasing rotational mass by 6.8 pounds per FRONT wheel. The 528i and 540i share the same rear brakes, so there's no change there.
> 
> The 528i front calipers are aluminum, while the 540i front calipers are iron. So the 540i calipers weigh about 7 pounds more per front corner. That's additional unsprung weight but it is not rotational.
> 
> I have done a few of these conversions and have helped others find the parts. Haven't heard any complaints about effect on handling or acceleration. I have heard a complaint from someone who installed M5 brakes on a 528i though.


 have heard a complaint from someone who installed M5 brakes on a 528i though.[/QUOTE]

What sort of problems? I have the M5 brakes installed on my 528 without problems.


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## DZeckhausen (Mar 11, 2003)

m5next said:


> What sort of problems? I have the M5 brakes installed on my 528 without problems.


He complained of slightly heavier steering, somewhat degraded ride over bumps, and weaker acceleration. It's similar to what you would experience if you installed some heavy 20" wheels.


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