Rear brake recommendation - 128i M Sport

[edycol]

Originally Posted by racer_951

Thanks guys for your recommendations! Very helpful. I bought the 135i from a BMW dealer mechanic. He mentioned he has rebuilt the calipers but didn't mention what what type of he used for the rebuild. I'll keep my fingers crossed and hope they hold up. I spent $500 for the 135i setup: rebuilt calipers, like new OEM rotors, and slightly used Hawk pads. I already track tested the fronts. Holding up pretty well except the power reduction "feature" at the end of the last session.

As for the rear, I bought a set of 328i calipers for now. My parking brakes are mostly gone. I went ahead and bought a set DS2500 328i pads and the parking brake kit from FCPEuro. Testing this setup at Sonoma raceway and Laguna Seca next month.

You might get away with 328i calipers once you install LSD and code out e.diff feature.
328 issue is pad not rotor. Basically you need more pad. 335 and Brembo from 135 would resolve issue if keeping e.diff. But with LSD, absolutely remove that feature.

[edycol]

Ok, based on debate here, I actually wanted to do small comparison between available pads for E82. I needed track pads for my E90 and on Rock Auto I got DFC (i need pads to get me through one more track day). But, I saw Bendix pads for 335 going for $10. I git them to compare to 328 and 135 Brembo rear pads.
Top pad is Textar for 135 rear brakes. Middle one is 335 and bottom is 328. Difference between 328 on one hand and 335 and 135 on another is more than obvious.
Choice is not quite easy between 335 and 135. Based on my observation I would say that 135 Pads for Brembo calipers is just slightly bigger, hardly noticeable (contact part). I am not sure it justifies price.

[Chris N]

I was logging in to start a new thread regarding a 135i brake conversion for my 128i. I figured best to start here and take advantage of the work that has already been done.

My wife and I absolutely cooked the 128i brakes (PF-08 pads w/high temp fluid) this past HPDE season. I also already have LSD with ediff coded out.

I chose the 135i setup simply because I am running 17x9 on the track and the 135i was the most cost effective option that would fit. I will be rebuilding the calipers with steel pistons and high-temp seals. I'm also converting the front backing plates to the F30 ones for the additional air venting scoop that they have.

I am okay with omitting the ebrake if that's the easiest option, however, is the drum diameter on the rear rotor the only limiting factor? I have a local industrial brake company that can add thicker linings to the 128i brake shoes to make up the difference. Wouldn't that be an easy fix to maintain ebrake functionality?

There was a thread that came close to answering this question, but stopped short...

[spidertri]

I'd skip the F30 backing plates, you really need to cut away as much of the backing plate as possible so that the heat isn't trapped next to the rotor. There's a picture floating around here somewhere showing just two pieces of the front backing plate remaining, up top between the rotor and the strut, and at the bottom where the ball joints are.

At the same time, trim away as much of the rear backing plate as possible. The stock design has the crazy lip over the whole edge of the rear rotor and it's terrible for trapping heat.

Yes, the rear rotor inner diameter is the only limiting factor if you are just swapping over to 135i calipers and rotors.

You should definitely be able to have a company that relines brake shoes just modify the stock ones to have a thicker lining. There are several people that have taken that approach on E90post.

What pads are you going to run on the rear?

[Chris N]

Originally Posted by spidertri

I'd skip the F30 backing plates, you really need to cut away as much of the backing plate as possible so that the heat isn't trapped next to the rotor. There's a picture floating around here somewhere showing just two pieces of the front backing plate remaining, up top between the rotor and the strut, and at the bottom where the ball joints are.

At the same time, trim away as much of the rear backing plate as possible. The stock design has the crazy lip over the whole edge of the rear rotor and it's terrible for trapping heat.

Yes, the rear rotor inner diameter is the only limiting factor if you are just swapping over to 135i calipers and rotors.

You should definitely be able to have a company that relines brake shoes just modify the stock ones to have a thicker lining. There are several people that have taken that approach on E90post.

What pads are you going to run on the rear?

Good call out on the front and rear backing plates. I will take a closer look at the opening them up during the install and modify as needed.

I haven't gotten to selecting my pads yet (I've instead been researching whether coding or a 135i master cylinder are necessary with this mod). I switch back and forth between track and street. Up until now I have been using PF P-08 on the track and Hawk street. I just had a rear P-08 pad delaminate, so I will very likely be moving away from them.

[spidertri]

A 135i master cylinder is a fantastic upgrade to the 128 braking system, it makes an immediate difference on track and engages the pedal higher up in the travel. It's one of the mods I wish I had done sooner.

Sucks that the pad delaminated, I've never had any issues running them. I wonder if they just got overheated too much. I only ask about the pad because you might want to check and see what is available. The 135i rear caliper was only used on that model and some pad manufacturers don't support it since it's such low volume.

[Chris N]

Did you have to do any coding after the swap?

[spidertri]

I didn't do any additional coding after the master cylinder swap. I do have all of the other brake nannies coded off or to the lowest setting.

[racer_951]

Thanks guys for all your input.

[amg6975]

Originally Posted by Chris N

I was logging in to start a new thread regarding a 135i brake conversion for my 128i. I figured best to start here and take advantage of the work that has already been done.

My wife and I absolutely cooked the 128i brakes (PF-08 pads w/high temp fluid) this past HPDE season. I also already have LSD with ediff coded out.

I chose the 135i setup simply because I am running 17x9 on the track and the 135i was the most cost effective option that would fit. I will be rebuilding the calipers with steel pistons and high-temp seals. I'm also converting the front backing plates to the F30 ones for the additional air venting scoop that they have.

I am okay with omitting the ebrake if that's the easiest option, however, is the drum diameter on the rear rotor the only limiting factor? I have a local industrial brake company that can add thicker linings to the 128i brake shoes to make up the difference. Wouldn't that be an easy fix to maintain ebrake functionality?

There was a thread that came close to answering this question, but stopped short...

For track use the 135 units are not a significant improvement over the 128. The E9x 335i brakes are BY FAR the best bang for your buck for a track set up. You could easily do the whole conversion for half what a set of 135 front calipers cost and they will be worlds better on track.

[Chris N]

Originally Posted by amg6975

For track use the 135 units are not a significant improvement over the 128. The E9x 335i brakes are BY FAR the best bang for your buck for a track set up. You could easily do the whole conversion for half what a set of 135 front calipers cost and they will be worlds better on track.

I agree that there are better options, but I want to stick with 17 inch wheels. I did a quick search and it looks like the 17s won't fit 335i brakes. Am I incorrect?

[dmytro98]

From my quick experience down the brake rabbit hole, my first route was e9x 335i fronts, e9x 328i rear with ds2500 pads. This setup was definitely not enough for the track, mainly due to terrible brake deposits that destroyed a set of rotors on it's first track day. After switching to dsunno pads the setup feels amazing and I was able to run full 30 min session being able to threshold brake confidently between these track days I also installed a clutch type lsd. Also, the brass bushings really help with vibrations and give the brakes a more reassuring feel. My recommendation for the original question is to just keep the stock rear calipers and get an aggressive track pad, dsunno is the only one I've tried but anything similar should do the trick.

[amg6975]

Originally Posted by Chris N

I agree that there are better options, but I want to stick with 17 inch wheels. I did a quick search and it looks like the 17s won't fit 335i brakes. Am I incorrect?

Apex ARC 8 will. I ran 17x9 et42 with my 335 set up.

[amg6975]

Originally Posted by dmytro98

From my quick experience down the brake rabbit hole, my first route was e9x 335i fronts, e9x 328i rear with ds2500 pads. This setup was definitely not enough for the track, mainly due to terrible brake deposits that destroyed a set of rotors on it's first track day. After switching to dsunno pads the setup feels amazing and I was able to run full 30 min session being able to threshold brake confidently between these track days I also installed a clutch type lsd. Also, the brass bushings really help with vibrations and give the brakes a more reassuring feel. My recommendation for the original question is to just keep the stock rear calipers and get an aggressive track pad, dsunno is the only one I've tried but anything similar should do the trick.

This is one big advantage of the 335 set up. Everyone and their sister makes pads for them. Can not recommend PFC-08s enough.

[edycol]

Originally Posted by amg6975

Apex ARC 8 will. I ran 17x9 et42 with my 335 set up.

Many E82/90 17" will fit F30 335 calipers with no issues. Buying F30 17" wheels is option too.
But, 370mm rotor version won't fit 17".

[Phloozy]

Originally Posted by spidertri

A 135i master cylinder is a fantastic upgrade to the 128 braking system, it makes an immediate difference on track and engages the pedal higher up in the travel. It's one of the mods I wish I had done sooner.

Sucks that the pad delaminated, I've never had any issues running them. I wonder if they just got overheated too much. I only ask about the pad because you might want to check and see what is available. The 135i rear caliper was only used on that model and some pad manufacturers don't support it since it's such low volume.

Would this be helpful even if still running stock 128 calipers?

[spidertri]

Originally Posted by Phloozy

Would this be helpful even if still running stock 128 calipers?

If you want less pedal travel before the brakes engage, then yes.

As Suprgnat has mentioned in other threads, the only difference is the take up volume, the 135/1M MC engages the calipers faster. The actual bore of the MC that applies pressure is the same between 128i, 135i, and 1M.

I'm impressed that you're still running the stock calipers at your level. How fast do you go through pads? I know you have ducts to the front, have you done any cooling mods to the rears?

[Phloozy]

Originally Posted by spidertri

If you want less pedal travel before the brakes engage, then yes.

As Suprgnat has mentioned in other threads, the only difference is the take up volume, the 135/1M MC engages the calipers faster. The actual bore of the MC that applies pressure is the same between 128i, 135i, and 1M.

I'm impressed that you're still running the stock calipers at your level. How fast do you go through pads? I know you have ducts to the front, have you done any cooling mods to the rears?

I actually have no cooling or pad wear issues lol if someone were to ask me I would say there is 0 need to touch brakes on the 128 outside of pads and fluid. Maybe my tracks are easy on brakes but I do about 7-10 events a year and my pads still have good life. I will say the brake feel is pretty mediocre so that's why I'm curious about the upgrading the master. I'll probably do it over the winter and see how I like it.

[Suprgnat]

Originally Posted by Phloozy

I actually have no cooling or pad wear issues lol if someone were to ask me I would say there is 0 need to touch brakes on the 128 outside of pads and fluid. Maybe my tracks are easy on brakes but I do about 7-10 events a year and my pads still have good life. I will say the brake feel is pretty mediocre so that's why I'm curious about the upgrading the master. I'll probably do it over the winter and see how I like it.

I thought the Bimmerworld brass guides and pins I mentioned above helped a lot with "feel" on the stock calipers.

[Phloozy]

Originally Posted by Suprgnat

I thought the Bimmerworld brass guides and pins I mentiohed above helped a lot with "feel" on the stock calipers.

I do have those and they were helpful for sure

[spidertri]

Originally Posted by Phloozy

I actually have no cooling or pad wear issues lol if someone were to ask me I would say there is 0 need to touch brakes on the 128 outside of pads and fluid. Maybe my tracks are easy on brakes but I do about 7-10 events a year and my pads still have good life. I will say the brake feel is pretty mediocre so that's why I'm curious about the upgrading the master. I'll probably do it over the winter and see how I like it.

Phloozy I suspected your better driving techniques and the fact that your car was a M-sport from the start (just for the factory air ducts) has meant you can set lap records and have no issue with the stock brakes. Doesn't hurt either that your car is gutted and has a lot less weight to slow.


My car started as a sport, with the base model front bumper cover and it was really easy to over heat the front brakes. In my mind it was two things, poor braking technique on track and no cooling air getting to the front rotors.

I try to work on my brake technique at every event, brake later, harder, and get off of them earlier. Don't ride them into a corner and generate excess heat. This has helped, and helped bring down lap times.

For cooling solutions, I ran the porsche front air deflectors mounted to the control arms, then a custom 3d printed brake duct in the non-M fog light location, and finally this year found a space gray M-sport bumper.

Each time I added more cooling air, the front brakes would last longer on track before feeling them get less effective. I've been very impressed with the pad wear and feel since I put the front m-sport bumper on. The stock ducts aim the air right at the back of the rotor, even with 17x9 and 255 tires.

[Phloozy]

Originally Posted by spidertri

Phloozy I suspected your better driving techniques and the fact that your car was a M-sport from the start (just for the factory air ducts) has meant you can set lap records and have no issue with the stock brakes. Doesn't hurt either that your car is gutted and has a lot less weight to slow.


My car started as a sport, with the base model front bumper cover and it was really easy to over heat the front brakes. In my mind it was two things, poor braking technique on track and no cooling air getting to the front rotors.

I try to work on my brake technique at every event, brake later, harder, and get off of them earlier. Don't ride them into a corner and generate excess heat. This has helped, and helped bring down lap times.

For cooling solutions, I ran the porsche front air deflectors mounted to the control arms, then a custom 3d printed brake duct in the non-M fog light location, and finally this year found a space gray M-sport bumper.

Each time I added more cooling air, the front brakes would last longer on track before feeling them get less effective. I've been very impressed with the pad wear and feel since I put the front m-sport bumper on. The stock ducts aim the air right at the back of the rotor, even with 17x9 and 255 tires.

Yeah I suspect the m sport front bumper is a big one that helped. I have a friend who is also very capable and he was having brake issues before swapping to the m sport. Either way anything to help cooling and braking won't hurt