Rear m brake

[POCti]

I've seen some people mention using z3 m brakes for the rear and I got a good deal on some M3 brakes and I was just going to install the front and maybe sell rear setup or maybe try and make a bracket so they would fit but was just thinking if I got the mount for the z3 m could I just put my m3 caliper and disk on there.

[Bloodrunsdry]

M3 rears fit directly. Not sure on the z3's, but standard M3 rears fit. Saw it on Bluebimma's car first hand, and I think he posted up pictars

[POCti]

Really I'll have to take another look at that maybe I just misunderstood what I've read about that. They don't look like they will fit but when weather passes I'll pull the wheel off and see. I'll see if I can't find bluebimma's builds I know he has had a few ti's he has built lol all nice

[POCti]

Ok so the rotor fits on is different? And in what way?

[cooljess76]

Originally Posted by POCti

Ok so the rotor fits on is different? And in what way?

M3 rotors are larger in diameter and thicker(being vented) than the ti rotors. Yes the calipers bolt right up to the ti trailing arms. However, if you tried to mount an M3 rotor onto the hub, the caliper will sit too low and will hit the rotor before the bolt holes will line up. Therefore, you'd have to use rotors that are the same diameter as the ti rotors. The 318ti's non-vented rear rotors are 272mm in diameter and 10mm thick. E46 323i and 323Ci's(not to be confused with e36's) use a 276mm X 19mm vented rear rotor. This means it's only 4mm larger in diameter than the non-vented 318ti rotor. The M3 caliper may or may not clear the E46 323i, 323Ci rotor. The E46 rotors are 19mm thick(being vented) which is really close to the thickness of e36 M3 rotors. E36 M3 rotors are 312mm X 20mm. So in short, if me and Bluebimma's theory is correct, you should be able to run M3 calipers with E46 323i/323CI rotors on the rear. Very important though, don't confuse the E46 with the E36. The E36 323i's use non-vented rotors.

[POCti]

Thats some good info thanks as soon as money starts coming in again and i can get it in a garage ill start tearing into that.

[Bloodrunsdry]

Thanks Jess! Forgot to mention that, ti rotors and M3 calipers. Still get the larger piston brakes in the rear. Just not vented.

[cooljess76]

Originally Posted by Bloodrunsdry

Thanks Jess! Forgot to mention that, ti rotors and M3 calipers. Still get the larger piston brakes in the rear. Just not vented.

I deleted my other post, but if you use ti rotors, you'll need to add a spacer to the brake pads to compensate for the thinner non-vented rotors. This would be to prevent the piston from hyperextending. Tony mentioned possibly using an old brake pad backing plate. Personally I like the idea of upgrading to e46 323i/Ci vented rotors better though.

[POCti]

Originally Posted by cooljess76

M3 rotors are larger in diameter and thicker(being vented) than the ti rotors. Yes the calipers bolt right up to the ti trailing arms. However, if you tried to mount an M3 rotor onto the hub, the caliper will sit too low and will hit the rotor before the bolt holes will line up. Therefore, you'd have to use rotors that are the same diameter as the ti rotors. The 318ti's non-vented rear rotors are 272mm in diameter and 10mm thick. E46 323i and 323Ci's(not to be confused with e36's) use a 276mm X 19mm vented rear rotor. This means it's only 4mm larger in diameter than the non-vented 318ti rotor. The M3 caliper may or may not clear the E46 323i, 323Ci rotor. The E46 rotors are 19mm thick(being vented) which is really close to the thickness of e36 M3 rotors. E36 M3 rotors are 312mm X 20mm. So in short, if me and Bluebimma's theory is correct, you should be able to run M3 calipers with E46 323i/323CI rotors on the rear. Very important though, don't confuse the E46 with the E36. The E36 323i's use non-vented rotors.

I just wanna make sure that i did mention this before i have the rotor caliper and mount of the 98 m3. and what im reading here is i can bolt the 98 m3 bracket and caliper to my trailing arms but the rotor won't go on because it will sit to low. Why is this if the mount and rotor and caliper were made for each other? Is it because of how the rotor fits on.

[cooljess76]

Originally Posted by POCti

I just wanna make sure that i did mention this before i have the rotor caliper and mount of the 98 m3. and what im reading here is i can bolt the 98 m3 bracket and caliper to my trailing arms but the rotor won't go on because it will sit to low. Why is this if the mount and rotor and caliper were made for each other? Is it because of how the rotor fits on.

It's because of where the caliper mounts onto the trailing arm in relation to the diameter of the rotor. Imagine if you tried to install a 8" rotor, now imagine if you tried to install 20" rotor. The caliper doesn't move up and down, it only moves in and out. Simply put, the ti rotors are much smaller than the M3 rotors. The calipers don't mount to the rotors, they mount to the trailing arms. You have two issues to address. One being the diameter of the rotor and the other being the thickness of the rotor.

[Bloodrunsdry]

Originally Posted by cooljess76

I deleted my other post, but if you use ti rotors, you'll need to add a spacer to the brake pads to compensate for the thinner non-vented rotors. This would be to prevent the piston from hyperextending. Tony mentioned possibly using an old brake pad backing plate. Personally I like the idea of upgrading to e46 323i/Ci vented rotors better though.

I see. I didnt get that far with Tony on this. Vented rotors would be nice on the rear. Not sure if its fully necessary, but would work well non the less. And less jank than just putting a spacer behind the pad.
Im sure if I was doing this right now, I would run a spacer. Ghetto yes, but thats how we roll in Toledo

[POCti]

Originally Posted by cooljess76

It's because of where the caliper mounts onto the trailing arm in relation to the diameter of the rotor. Imagine if you tried to install a 8" rotor, now imagine if you tried to install 20" rotor. The caliper doesn't move up and down, it only moves in and out. Simply put, the ti rotors are much smaller than the M3 rotors. The calipers don't mount to the rotors, they mount to the trailing arms. You have two issues to address. One being the diameter of the rotor and the other being the thickness of the rotor.

Ok i was wondering if it was because of the trailing arm but wasnt sure if thats what you were getting at or if you thought i was trying to use the ti caliper bracket. LOL thanks for clearing that up.

[BenM]

Very interesting thread!

I just picked up a pair of rear 2000 E46 323i rotors (276mm x 19mm) to try to fit to my E30 w/ Ti Rear Trailing Arms and E36 M3 Rear Brakes.

I work in a machine shop so turning down the rotor diameter (hopefully only 2-4mm total) and making a 1mm shim spacer for the caliper carrier should be pretty painless. Only dilemma I'm concerned with so far is the E46 323i rotor fitment on the Ti trailing arm, but will keep you all updated.

[cooljess76]

Originally Posted by BenM

Very interesting thread!

I just picked up a pair of rear 2000 E46 323i rotors (276mm x 19mm) to try to fit to my E30 w/ Ti Rear Trailing Arms and E36 M3 Rear Brakes.

I work in a machine shop so turning down the rotor diameter (hopefully only 2-4mm total) and making a 1mm shim spacer for the caliper carrier should be pretty painless. Only dilemma I'm concerned with so far is the E46 323i rotor fitment on the Ti trailing arm, but will keep you all updated.

I don't think the 1mm shim is really necessary since the pads wear more than 1mm. The 4mm difference in diameter might even clear.

[POCti]

Ya would like to see how that turns out I went to school for machining and manufacturing didnt prose it as career but I should be able to find that can do it cheap or maybe do myself lol but been to long so rather have buddy do it lol