Stoptech ST-60/ST-40. Anyone have any regrets

[Pyrat 2]

Just ordered this BBK and wanted to double check to see if anyone who already owns it has any regrets. It's relatively big $s and I just want to make sure I'm not making a mistake. I am buying the kit because I have no confidence in the stock brakes when at the track. I run Motul RBF600 and currently Ferodo DS2500s and I end up with warped rotors after a weekend at Road Atlanta. Caliper rebuilds...enough.

Anyone?

[Kgolf31]

I don't think you'll be disappointed to regretting it. You'll be able to go deeper in the brake zone and stand on the pedal.

It's one of the items I want to get done sooner or later, mostly for rotational mass savings (if any) for autox

[Bullitt]

Originally Posted by HeelToe

...
Caliper rebuilds...enough.
...

Rebuilding with better pistons didn't help?

I want this same BBK but was considering to try the RB rebuild kit first.

[c0ris07]

Regrets? No. The only thing you won't have is the initial bite of the stock dust makers. But what you do get is consistent breaking feel through the whole pedal, which is a much better feeling.

[lakefront]

Just wondering if the OP considered just the front kit? Are the rear brakes that subject to overheating? Just asking because guys at Stoptech said that installing just a front BBK would not upset the F/R bias.
Thanks. I will have to make this decision soon too.

[Pyrat 2]

I know that's an option. I like the idea of a matched set. Plus fwiw the paint on the rear calipers has discolored and turned gold from the heat already whereas the fronts haven't.

[wjk_glynn]

Originally Posted by HeelToe

Just ordered this BBK and wanted to double check to see if anyone who already owns it has any regrets...

Not regret but...

Originally Posted by c0ris07

Regrets? No. The only thing you won't have is the initial bite of the stock dust makers...

After install the ST60, I experienced a small amount of variability in brake pedal travel/pressure from application to application. Sometimes it was rock hard, sometimes there was a small bit of squish... And this happened from block to block, during regular driving around town.

The shop that did the install is very reputable (they even raced their own 135i) and I trust their work. The wheel bearings are good, the brakes were bled a few times with Endless RF-650 fluid, etc...

They said what I described was the classic symptom of knockback, but I'm struggling to believe that I could get even a hint of that in 35-40 mph suburban driving. It should be noted that when they took the car on test drives, they didn't see (or more accurately feel) this issue. These are good & experienced guys. But I swear that minor variability was there for me.

Now over time (12+ months), it has gotten better to the point that I only notice it now maybe once per week. And any time I've ever tried to replicate it under "controlled" circumstances, it doesn't happen.

Maybe there was some air in the system that proved stubborn to get out, or maybe I have the equivalent of automotive hypochondria.

But I will say that the OEM brake feel is (in hindsight) really great for day to day driving. You may seen some minor degradation in that initial bite with the ST60 as c0ris07 pointed out.

Originally Posted by lakefront

Just wondering if the OP considered just the front kit?

Originally Posted by HeelToe

I know that's an option. I like the idea of a matched set. Plus fwiw the paint on the rear calipers has discolored and turned gold from the heat already whereas the fronts haven't.

I specifically got just the front setup (p/n 83.165.6700.51) because:

• It is by design meant to have the correct bias when paired with the OEM rears
• And the aforementioned shop's racing experience (w/135i) was that the rears didn't need upgrading.

I'd still recommend only getting the fronts and saving a chunk-of-change to put towards a LSD/torsen-differential (and maybe painting your current discolored rears), and that may help if your rear brake heating issues are caused by ediff operation.

Karl.

[Pyrat 2]

Thanks for the input. Already have a quaife in back. I'll post when installed. They haven't even shipped yet. Just paid for them yesterday.

[Bullitt]

HeelToe, I wasn't sure in your original post if you meant you already tried rebuilding the calipers. It'd be helpful to know. If so, I'll have to think twice about going that route and just go BBK as you have.

[Nugget]

No regrets, along with the LSD it's one of the best changes I made to this car.
I did front only, currently running DS2500 in rear, Endless ME20 in front. Maybe not a perfect match but it pulls up hard and consistently on the street (from cold) and on track.

In regards to the knockback issue mentioned above, in the 2 years I've had them installed I have noticed it one time, it was after going through multiple long sweeping turns. The pedal needed a second pump before it actually staring working properly. Slightly disconcerting but I always leave margin for error on the road so I pulled up fine. I have never experienced it on track.

And a pic of them at work just because

[Pig Farmer]

Originally Posted by wjk_glynn

After install the ST60, I experienced a small amount of variability in brake pedal travel/pressure from application to application. Sometimes it was rock hard, sometimes there was a small bit of squish... And this happened from block to block, during regular driving around town.

The shop that did the install is very reputable (they even raced their own 135i) and I trust their work. The wheel bearings are good, the brakes were bled a few times with Endless RF-650 fluid, etc...

I had a similar experience after the initial bleeding of the ST60s using a motive pressure bleeder. Using the two person bleeding method (i.e. Pump, hold, bleed, repeat etc.) solved 95% of variability. What's more interesting is that the variability was completely gone after installing my Cobb. During the Cobb install you can here the ECU activate a sorts of pumps. I assume it activated the ABS and released whatever air may have been trapped in the system? All I know is it fixed variability.

Also, the variability did not return after numerous fluid changes, although I always use the two person method after using the pressure bleeder.

[wjk_glynn]

Originally Posted by Nugget

...And a pic of them at work just because

Fantastic photo.

Karl.