Stock 125i brake improvement possible?

[janus77]

Hi All, i've thrown around the idea of upgrading to a set of used 135i brakes, but I'm getting married in 6 weeks and don't really want to spend the sort of money required.

I'm wondering if there are any brake enhancements possible with the stock brakes to give better performance at the limit? Ie. new performance rotors and some different pads.

Rotors i guess will help as they'll be slower to heat and cool faster, and i can potentially hook up some kind of vent to get air to them, and pads i might find something that grips a little better.

I find the brakes good for most driving, however when pushed they feel weak, the ABS kicks in too early, and they don't give a solid bite. Can this be improved with new rotors and pads?

Cheers

[Dackelone]

You should get the Performance Brake Kit. 135i bits made to fit on your car. The 135i rotors won't fit on your car... but BMW designed a special kit with almost the same sized rotors as a 135i. The 128i PBK is slightly smaller rotors with 135i calipers. Plus you need to have the ABS system re-coded. This really is a good way to go.

[janus77]

Issue is the cost, don't really want to pay too much, and the PBK is not going to be cheap..

[Stuart@BMRAutowerkes]

Start with upgraded brake pads?

Then slotted rotors for your calipers?

[jksgoh]

Dunno much about the brakes, but congrats on the wedding!

[BMWRX]

Where is the best place to order performance rotors for a 135i? And what pads have people upgraded to?

I thought it best jump into here rather than start a whole new thread.

[Stuart@BMRAutowerkes]

BMW Perf Rotors? Tischer has them at $189 each (fronts) before shipping, i'd expect shipping to be about ~$60-80 for both seeing as they are pretty heavy...

I was going to use cool carbon pads, they have good reviews and seem like good value as well. I was going to get my cool carbons from SonicMS..

[dtcoff]

If the ABS is cutting in early, then the brakes are working ok (unless one corner has an issue) as ABS is triggered by a difference in wheel rotation. Seems more like a tyre grip issue. Cheap upgrades are changing to braided brakes lines as they have less flex than the standard rubber lines. Be careful when upgrading pads as they all have optimum temp ranges, ie standard pads work well in the colder ranges for normal road usage, but the track pads etc don't work at all when cold.

[janus77]

Thanks for the advice, i've got pretty new Z1's all round so grip isn't an issue, maybe it isn't ABS, but it feels weird at the limit, like they grip and let go as if the pads are fighting to maintain friction. I figured it was the abs, but maybe not? there's a bit of a squeak noise too, and i can feel it through the brake pedal.

Like i said it's only on the limit, like if you're hooting into a 25k/hr corner at 110 and want to dust your speed fast before you start your turn in.

Can i run the performance rotors with the stock calipers?

[janus77]

Originally Posted by jksgoh

Dunno much about the brakes, but congrats on the wedding!

Cheers man.

[Stuart@BMRAutowerkes]

Originally Posted by janus77

Can i run the performance rotors with the stock calipers?

nope... stock 135i calipers yes, not 125i calipers though.

[dtcoff]

Originally Posted by janus77

Thanks for the advice, i've got pretty new Z1's all round so grip isn't an issue, maybe it isn't ABS, but it feels weird at the limit, like they grip and let go as if the pads are fighting to maintain friction. I figured it was the abs, but maybe not? there's a bit of a squeak noise too, and i can feel it through the brake pedal.

Like i said it's only on the limit, like if you're hooting into a 25k/hr corner at 110 and want to dust your speed fast before you start your turn in.

Can i run the performance rotors with the stock calipers?

Dumpy roads (all Sydney) can cause this too as the suspension loads and unloads differently on each corner. Under heavy braking one wheel can lock causing ABS to activate.

[Cruiser]

Originally Posted by bmroxm5

nope... stock 135i calipers yes, not 125i calipers though.

Yes of course you can run stock calipers as long as you get aftermarket rotors designed for the 125/128.

There are several brands available that offer slotted and cross drilled. But they are going to cost a bit after overseas shipping.

Factor in changing the pads too when you switch rotors.

[DriveHard]

i think in your case, you need the following:

New pads.. OEM pads have a great initial "bite" but then fall off. Maybe Cool Carbons, they have a much more Linear bite at all speeds.. it may be just the thing you want considering how you felt about the OEM pads dropping off. The bonus is they dust less also and you can still use the oem sensors. They also fit very well.

also, bleed the brakes.. If you want to go one more level up and still be "within budget" you may want to try stainless steel brake lines.. they give the sensation of a firmer pedal as they dont expand as much as rubber lines do..

I have the BBK and there is no substitute but you have priorities....your wife.. I divorced mine !!!! my priorities are set now.. LOL

[BMWRX]

Where is the best place to get cool carbon pads? Are the braided lines a BMW Performance item?

[janus77]

Thanks guys, the cool carbon's sound like a good option, and maybe the braided lines (can you really tell the difference with them?).

like BMWRX, i'm interested to know the best place to pick a set up.

[Stuart@BMRAutowerkes]

For this interested in CC pads cal@sonic ms quoted me $380 USD landed for front and rear set (unless I misunderstood and he meant per axle or something)...

janus77 I haven't purchased mine yet so why dont I get him to ship a set for the 125i if you're interested and we can save a few $?

edit: assuming they have CC pads for the 125i brakes as I only enquired on the 135i brakes...

[Jeef Beef]

The only issue I'd have with cool carbons is that you might chew through rotors more frequently. And that's expensive.

[janus77]

Originally Posted by bmroxm5

For this interested in CC pads cal@sonic ms quoted me $380 USD landed for front and rear set (unless I misunderstood and he meant per axle or something)...

janus77 I haven't purchased mine yet so why dont I get him to ship a set for the 125i if you're interested and we can save a few $?

edit: assuming they have CC pads for the 125i brakes as I only enquired on the 135i brakes...

i'd be interested to find out what pads for the 125i for all 4 corners would cost.