Quote:
Originally Posted by hardparker
More X3 upgrade goodness from Tro-Nik!
Tro-Nik G30 M Sport front brake upgrade
Notice that there's no bracket. This means that G30 calipers are a direct fit for F25 X3 front brakes. All that's needed is the center bore spacer to adapt the sedan's larger hub bore diameter down to the SUV's hub size. Strange that all of the BMW SUVs use smaller hub bores than the sedans.
I'll figure out the hub bore sizing and post up when I do. If anyone has time to measure or look it up first, please do. It needs to be the hub rotor diameter, BTW, not the wheel bore diameter. They're different. Measurement with calipers would be best. |
I agree with your conclusion on the rotor, they're using the E60 M5 rotor.
I tried to do a little homework on the caliper. Looking at the caliper for a G30, the numbers are different by trim:
530 (running a 348x36 rotor)
34 11 6 880 303 - left
34 11 6 880 304 - right
540/550 (running a 374x36 rotor)
34 11 6 880 305 - left
34 11 6 880 306 - right
I also looked up the 2018 X3 M40
G01 M40 (running a 348x36 rotor)
34 11 6 884 879 - left
34 11 6 884 880 - right
The G30s use pads with part number 34 10 6 888 459, while the G01 used 34 11 6 88 457. The Brembo data sheet for pad P 06 099 shows compatible vehicles as the new 5 and 6 series (non-M cars), 7 series and new X3s.
I wonder if there really is a difference on the physical shape of the calipers for those cars (different bolt location, offset side to side, or height; i.e. distance away from the center of the hub). I doubt the bolt locations are different, I'm sure BMW tries to standardize that across platforms. That said, I wouldn't be surprised if the calipers for the larger rotors were further from the hub, in theory the 1 inch larger rotor has a sweep area 1/2 an inch away from the hub, so the caliper may be moved out 1/2 an inch to accommodate.
The two primary questions that I have are:
1) Does it matter which car the caliper comes off of, and
2) While Tro-Nik opted for the E60 M5 rotor with a 374x36 size, is there a caliper and rotor setup that would work using a 348x36 disk? Possibly even a non-M two piece disk that could keep the costs down. That would still be an increase from the 328x28 size of the 3.5i X3, and would be close to the 348x30 of the F26 X4 M40i. That seems like it would help address the issue of brake bias. If 348x36 is sufficient for the new X3 M40, I'd think it would be good for us too.
I wonder if there's a caliper that would bolt to the X3 hub that would work with a F26 X4 M40 disk? The rotor is a little thinner, so the pads would have to go 3mm further on each side, but I'd assume that would be okay. If everything else physically lined up...