Brembo on a budget! Let's make x5 great again :)

[spacegray_f15]

Okay lol, what are everyone's thoughts on having such a small rotor in the rear and such a massive rotor in the front? Does it look funny? Personally I don't think it's worth it for the $$/unsprung weight

[DuSh]

Originally Posted by spacegray_f15

Okay lol, what are everyone's thoughts on having such a small rotor in the rear and such a massive rotor in the front? Does it look funny? Personally I don't think it's worth it for the $$/unsprung weight

I left rear ones alone just because I was lazy and impatient, but getting proper rotor on rears too is of course much better. It doesn't look small as it's still 50i rotor - which is by default bigger than majority of cars on the road. In addition when it's drilled or slotted and calipers are color matched - it doesn't look funny at all IMHO, but I have 20 inch rims. With larger rims like 21 and 22 this might be more apparent, so I'm not sure lol. Then again it's not small compared to other cars. I can only count several models that have bigger rotors in rear.
As for weight - it's minimal difference man for rears - on such a heavy SAV like x5 it's pennies. As for fronts - brembo calipers weigh almost same as stock 50i calipers (I'm guessing stock is cast iron, while brembo ones are aluminum) - so for fronts we are only adding weight with larger rotor - still some more weight compared to stock rotor, but the only alternative is ceramic brakes from M5 - which are $10-20k for a set.

[spacegray_f15]

Originally Posted by DuSh

I left rear ones alone just because I was lazy and impatient, but getting proper rotor on rears too is of course much better. It doesn't look small as it's still 50i rotor - which is by default bigger than majority of cars on the road. In addition when it's drilled or slotted and calipers are color matched - it doesn't look funny at all IMHO, but I have 20 inch rims. With larger rims like 21 and 22 this might be more apparent, so I'm not sure lol. Then again it's not small compared to other cars. I can only count several models that have bigger rotors in rear.
As for weight - it's minimal difference man for rears - on such a heavy SAV like x5 it's pennies. As for fronts - brembo calipers weigh almost same as stock 50i calipers (I'm guessing stock is cast iron, while brembo ones are aluminum) - so for fronts we are only adding weight with larger rotor - still some more weight compared to stock rotor, but the only alternative is ceramic brakes from M5 - which are $10-20k for a set.

Do the rotors you have match (lookswise) ? I haven't found a set of M fronts and non M rears that match, they all have different patterns

[Maverik259]

Originally Posted by spacegray_f15

Do the rotors you have match (lookswise) ? I haven't found a set of M fronts and non M rears that match, they all have different patterns

They won't be exact. But you just need drilled.

[DuSh]

Like Maverick said it's not 100% match in drilled pattern lol. However, IMHO it looks good. i mean unless you are prepping your car for SEMA show or some other competition - it should be just fine. Even oem x5m rotors don't have exact drill pattern matching rears and fronts - still little differences.

[DuSh]

I got couple PMs about possibility to install F10 M5 6 pot calipers and rotors on our x5 or x6 cars. I'm going to answer it here, since this is something that many would like to know and there is no secret in anything like this lol:

It's possible and you need a adapter - something like this (there's many of them on ebay):
https://www.ebay.com/itm/BMW-X5-X6-F...-/292743441563

Also, if I'm not mistaken Maverick has that project planned and I'm sure he'll be able to answer some questions better than me as I haven't even seen 6-pot calipers in person - that's next level of performance

[Maverik259]

Originally Posted by DuSh

I got couple PMs about possibility to install F10 M5 6 pot calipers and rotors on our x5 or x6 cars. I'm going to answer it here, since this is something that many would like to know and there is no secret in anything like this lol:

It's possible and you need a adapter - something like this (there's many of them on ebay):
https://www.ebay.com/itm/BMW-X5-X6-F...-/292743441563

Also, if I'm not mistaken Maverick has that project planned and I'm sure he'll be able to answer some questions better than me as I haven't even seen 6-pot calipers in person - that's next level of performance

You don't need the adapter if you want M5 rotors and M5 calipers. Just if you want to run the M5 caliper with X5 295mm rotors. The caliper is the same design it just sits further from the hub.

It's possible but rotors are much more expensive and even less options than X5M. If you can find a cheap set then sure. If they got a lot of meat left it can last you 10s of thousands of miles. But you'll pay for it in the back end.

[sbinshihon]

I got this wired vibrations when I brake in speeds around 80-90 miles.. only the initial bite if I press harder it goes away!

I tired changing the rotors, pads, suspension bushings.. and did alignment, balance etc. still nothing helps. Any idea what could be the cause? I have the MPBK at the front, rear is stock.

[DuSh]

Originally Posted by sbinshihon

I got this wired vibrations when I brake in speeds around 80-90 miles.. only the initial bite if I press harder it goes away!

I tired changing the rotors, pads, suspension bushings.. and did alignment, balance etc. still nothing helps. Any idea what could be the cause? I have the MPBK at the front, rear is stock.

What kind of rotors do you have on front, are they stock for MPBK ones or drilled f85 or 3rd party aftermarket ones? Does the steering wheel vibrate - meaning it's front wheels issue or no steering wheel vibration (rear ones)? What pads?

[sbinshihon]

Originally Posted by DuSh

What kind of rotors do you have on front, are they stock for MPBK ones or drilled f85 or 3rd party aftermarket ones? Does the steering wheel vibrate - meaning it's front wheels issue or no steering wheel vibration (rear ones)? What pads?

I have front OEM MPBK rotors & pads.. the vibration is not in the steering, its more the whole car.. clearly seeing in the center console.

Now I suspect the calipers since I bought them used off Ebay and didnt do the rebuild kit. Could it be that? Or maybe because of the size difference between front/back(35i) since this appears in such high speeds... everything else looks good I had inspected the car many times.

[DuSh]

Originally Posted by sbinshihon

I have front OEM MPBK rotors & pads.. the vibration is not in the steering, its more the whole car.. clearly seeing in the center console.

Now I suspect the calipers since I bought them used off Ebay and didnt do the rebuild kit. Could it be that? Or maybe because of the size difference between front/back(35i) since this appears in such high speeds... everything else looks good I had inspected the car many times.

Nah size difference have nothing to do with it. The weird thing is that if it's not in the steering - then it might be rear ones. You would have felt it in steering if it was front calipers/rotors - there's no way not to feel it. If your rear rotors are not changed - could it be they are worn/warped?

[sbinshihon]

Originally Posted by DuSh

Nah size difference have nothing to do with it. The weird thing is that if it's not in the steering - then it might be rear ones. You would have felt it in steering if it was front calipers/rotors - there's no way not to feel it. If your rear rotors are not changed - could it be they are worn/warped?

I did the rears too, pads&rotors NEW Oem! I really dont know whats causing it.. starting to hate the car because of this issue.

[Maverik259]

Originally Posted by DuSh

Nah size difference have nothing to do with it. The weird thing is that if it's not in the steering - then it might be rear ones. You would have felt it in steering if it was front calipers/rotors - there's no way not to feel it. If your rear rotors are not changed - could it be they are worn/warped?

Why don't you think size has anything to do with it? What's the size difference of the 35i rear rotor? Could be creating a big brake force difference. Maybe?

[Localbrew]

I tend to think you either got a defective rotor (although not likely) or it could be the calipers, you might need to rebuild them unfortunately.

The only other thing I could think of would be if the rotor is not seated properly but then I doubt it would all bolt up.

[sbinshihon]

Originally Posted by Maverik259

Why don't you think size has anything to do with it? What's the size difference of the 35i rear rotor? Could be creating a big brake force difference. Maybe?

I was thinking the same, since this happens in such high speeds, the difference is big.

The only way to know is to install the MPBK kit in the rear tho..

[sbinshihon]

Originally Posted by Localbrew

I tend to think you either got a defective rotor (although not likely) or it could be the calipers, you might need to rebuild them unfortunately.

The only other thing I could think of would be if the rotor is not seated properly but then I doubt it would all bolt up.

I will try to take off the front calipers and see if anything seems off.. maybe check engine mounts and other stuff while am at it.


The next step is to put back the original calipers, if things get better Ill rebuild the front MPBKs calipers.

[mikew2069]

Originally Posted by sbinshihon

I will try to take off the front calipers and see if anything seems off.. maybe check engine mounts and other stuff while am at it.


The next step is to put back the original calipers, if things get better Ill rebuild the front MPBKs calipers.

When you're going that speed, does it happen even if you aren't braking? Or braking lightly or hard or both?

[sbinshihon]

Originally Posted by mikew2069

When you're going that speed, does it happen even if you aren't braking? Or braking lightly or hard or both?

It doesn't happen until I touch the brakes, if I press really hard it goes away.. not sure if thats related to already reduced speed.

[DuSh]

Originally Posted by Maverik259

Why don't you think size has anything to do with it? What's the size difference of the 35i rear rotor? Could be creating a big brake force difference. Maybe?

Oh I didn't realize he has 35i, I thought 50i lol. I could be wrong (like many times previously here on forum lol). However, the thing is if let's say his front brakes are overpowering his rears - he still shouldn't have vibration. He will just have a front biased system - maybe at most his front end will dive a bit more when brakes are applied. I mean vibrations should physically come from some force that is causing it - like warped rotor for example. But I could be wrong.
I'm thinking how to best test this to rule out or pinpoint the issue? If we could disable temporarily rear or front brakes, we could for sure eliminate one or the other, but that could be dangerous. Maybe he could raise it on the hoist at local shop (will cost some diagnostic money), run the engine in Drive (in air) and apply brakes slightly - to check if there will be some vibration on front or rear wheels - if he says whole body shakes - it should be visible?

[DuSh]

Originally Posted by sbinshihon

I was thinking the same, since this happens in such high speeds, the difference is big.

The only way to know is to install the MPBK kit in the rear tho..

Does it happen on every speed like 35mph or above certain speeds like highway speeds?

The only thing why I'm not thinking it has anything to do with brake distribution between front and rear axle is: imagine the worst case scenario (biggest difference) you had no rear brakes at all and all your stopping power comes from front end - what will happen? Will you have crazy vibrations? I think nothing will happen, you'll just stop a bit later due to less stopping power. Issues with brake force distribution should arise if you have uneven distribution between 2 front wheels or 2 rear wheels - on that case car will tend to steer towards left or right kinda if you know what I'm saying. I'm trying to think where from should vibration come? For vibration there has to be some physical impulse causing it - like some frequency - let's say 20-30 times per second or so. besides warped rotor that does exactly that when its rotating - I'm not sure how can brake difference cause it? Maybe some master cylinder thing that senses some force difference between front and rear hydraulics and gets confused and starts to pump on and off (like ABS)? maybe something like that you think? BTW could it be ABS kicking in lol?

[DuSh]

I'm an idiot. If you are saying there's no vibration when you press pedal all the way - then it can't be rotors - because they would vibrate in any case (they won't suddenly stop vibrating when brake pedal is pushed all the way). So at least that we know it's not rotors imho.

[sbinshihon]

Originally Posted by DuSh

Does it happen on every speed like 35mph or above certain speeds like highway speeds?

The only thing why I'm not thinking it has anything to do with brake distribution between front and rear axle is: imagine the worst case scenario (biggest difference) you had no rear brakes at all and all your stopping power comes from front end - what will happen? Will you have crazy vibrations? I think nothing will happen, you'll just stop a bit later due to less stopping power. Issues with brake force distribution should arise if you have uneven distribution between 2 front wheels or 2 rear wheels - on that case car will tend to steer towards left or right kinda if you know what I'm saying. I'm trying to think where from should vibration come? For vibration there has to be some physical impulse causing it - like some frequency - let's say 20-30 times per second or so. besides warped rotor that does exactly that when its rotating - I'm not sure how can brake difference cause it? Maybe some master cylinder thing that senses some force difference between front and rear hydraulics and gets confused and starts to pump on and off (like ABS)? maybe something like that you think? BTW could it be ABS kicking in lol?

Thank you for the detailed response, it sparked some thoughts..

Like I said it mostly happens at highway speeds, lower speeds doesn't vibrate but feels a bit off.. the car feels unsafe at higher speeds. Throwing electrical things into the equation makes it even more complicated to solve!

Whats interesting while I was searching the forums I found a F15 thread with a similar issue, the dealer changed his brakes 3 times and it still vibrates.. I sent him a PM, he said the dealer finally solved his issue by re bedding the brakes!