Brake review: Stoptech ST40's BBK w/ Raybestos ST43's
 

Just did a track event last weekend at Barber Motorsports Park. Running my NA BRZ w/ the Stoptech ST40's up front and Raybestos ST43's all around. Tires are BFG Rivals 245/40/17. The consensus? Far over-braked for street tires.

Around 30% brake input results in locking up the front wheels. Total lack of progressive pedal feel. The upside is there is absolutely no hint of fade or anything. This would have been better with the stock calipers up front i'm thinking - but i'm almost convinced the ST43's are far too aggressive for street tires. My confidence on heavy braking was certainly increased but it just required a very delicate foot to not lock up the fronts.

I previously had Carbotech XP10's and quite enjoyed the pads minus some issues with uneven pad transfer and noticing a hint of fade later on in sessions. The Carbotechs were VERY progressive and gave you a much better feel of what was going on. The Raybestos ST-43 pads are almost like a light-switch with the BBK. It took me 3 sessions until i finally became comfortable with how little brake input was necessary.

I'm going to do Road Atlanta this upcoming weekend with the pads - hopefully with a little better knowledge of how the pads work i'll be alright. Definitely would not recommend these pads with a BBK to anyone except an advanced driver.

You definitely need your tires matched to your brakes. Are you in a position to put some upgraded rubber on the car for track days?

You mentioned locking the fronts - how was your ABS responding to the pad/tire mismatch?

I really don't want to go with R-compound so i'm not sure there is much to be done for upgrading from Rivals.

I don't believe i got so deep into the brakes that ABS actually engaged. I'd just get on the brakes hard, hear/feel the fronts sliding and get out of them quickly. I was not doing the pedal dance FWIW

If you're getting to ABS engagement and there's still that much headroom on the system... why not dial back the pad?

I've always heard that you should use the least aggressive pad that gets the job done (read: doesn't catch fire, melt, or glaze)

Raybestos ST43's are solid pads, designed for motorsports use. There's nothing wrong with that, but a more mild option could be in order. They have 4 race pads and 2 street pads listed on Stoptech's site... and I'm sure others exist in this size.

http://www.stoptech.com/images/frc-b...g.jpg?sfvrsn=6

I'll definitely dial-back the pad eventually. At around $400 a set these pads are not cheap so it's not like i'm carrying various sets to test.

And you're absolutely right. Least aggressive pad possible to get the job done. This is a great example of a total mismatch and it really takes away part of the fun of the car.

I am going to be using AP racing Sprint and XP10 in a month with 225 RE11A , will be interesting to see how it feels.

XP10's should be pretty dang good. The only real complaint i had was pad transfer. Otherwise they're fairly solid brakes. Oh, and they squeeled like a pig even off brakes - couldn't drive with them on the road. Even my ST43's are more streetable even though they're super loud once you're on the brakes.

Thanks for the honest feedback

^^
exactly,

ST43s, IMHO, the best pads you can buy for the money especially for those who want threshold/trail braking, more initial bite and longer pad life, they're also street-able .. so for better modulation and stopping power you may want to combine them with a better suited tires for track use or adopting your braking technique

I wanted to give it a try to Carbotech XP12s before I turned back to ST43s and XP12s sucked big time.. yes it had the OEM like brake feeling (to some extent) but it suffered from fading, premature and uneven wearing

I would definitely match them with better tires for summer/track combined use,, Nitto NT01s are really cheap for what they offer and you can always get some Enkeis in case you want to swap the tires/wheels at the event.. so you won't destroy your street tires quickly (since they're not designed for track use and can be overheated easily) ..my 2 cents

I've been extremely happy with XP12s on stock brakes with cooling ducts and PSSs and AD08s.

I think pads are like ice cream; everyone has a preference and that's why there are so many flavors :)

Basically, you have to try several before you find your favorite(s).

I just got a chance to do a faster track this past weekend at Road Atlanta. Brakes performed really well, absolutely 0 fade or signs of fatigue. Still not as progressive as i'd like and mis-matched for my tires but they'll do some serious work when pushed.

[ame="https://www.youtube.com/watch?v=sZjDOAioVlA"]Road Atlanta - Chin Motorsports - Subaru BRZ - 9/28/14 - Session 2 - Green - YouTube[/ame]

On a slightly more interesting note my fastest lap time had an average speed of 86.6mph. Coincidence? :P

Pete, have you ever tried the XP12s at ORP? :) on tighter courses like ORP where you don't have enough space to cool down the brakes between turns they fade noticeably, even with the ducting .. this is not a big of a deal at RMP but at ORP fade is almost guaranteed, especially at T1 and T3 (even with NA power)

Another issue is the premature pad life and tapering (both are not an issue with ST43s) .. I agree with you on personal preference comment by the way, I think my ideal pad would be something that feels like XP12s but last like the ST43s :D


I was able to adopt the ST43s and street tires when I had my Vette but in the long run having a second set of wheels and tires is less expensive (consumables ), safer and faster, I'm just saying :)

I didn't have any fade issues at ORP even without the ducts. No tapering issues either.

I get about 5 track days per set of front pads which I don't find particularly premature.

My car has stock power and the stickiest tires I've run are 235 AD08s. Given your supercharged power and use of R-comps, I'm guessing those are going make a big difference on brake performance needs/stress. Frankly, I'm surprised you can run on stock calipers! :bow: