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Stoptech ST40/328mm BBK

2015WhiteGTI

Go Kart Champion
I've finally gotten some pics of my Stoptech BBK with my Volks installed.

The kit is the ST-40, 328x28 with PN 83.895.4300.XX. I did not have the PP on my car and wanted an upgrade in my braking. I have extensive history with Stoptech BBKs over the last 11 years. I had four corner BBK on my BMW 330 that I used for both street and track along with running the same kits on the BMW 335 that I endurance race with a friend of mine. We've NEVER had any issues with the BBK. The pads are what make all the difference (started with Carbotech - junk and ended up with Pagid - stellar).

That being said, I didn't think I wanted to go with the stock PP brakes due to the lack of pad choices and the ease of changing pads of the Stoptech is stellar. Of course, I have a familiarity with the Stoptech product so that helped with my choice. I didn't feel the need to go with a 355mm rotor either since the vast majority of time would be spent on the street (99% would be street driven).

I was concerned that I was going to be sticking with the solid rear rotors and worried about balance. I've spoken to Stoptech over the years about their designs and know that they design their BBKs to balance the braking so you don't get any unnecessary dive or rear lock-up. I was thinking about changing pads in the rear to something a little more aggressive along with Stoptech slotted rotors for the rear as well. I have recently found out that the VW TCR race car uses the stock solid rear discs as well. VERY little braking is done with the rears (our race car will last 12 hours for the front pads and the rears have gone well over 24 hours with still pad life left - Pagid RS29).

My fears were for nothing. The balanced feeling during hard braking is still there. There is no reason to do anything to the rears. The car tracks straight and the braking upgrade from the stock brakes is very noticable. Especially once you get some heat into the brakes (and that's using the street pads that are supplied from Stoptech). This is a worthy upgrade.
The stock Austins fit with a 5mm spacer. My Volk TE37SL BLK fit with plenty of space to spare. I was able to fit the 6-piston, 355mm template into the wheel without any issues. That's the advantage of a smooth barrel and a design specifically to fit over BBKs.

The fact that you can get this type of an upgrade for about $1700 is well worth it. I'm loving them.
 

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GTI Jake

Autocross Champion
Location
Charlotte, NC
My car wants to be like yours when it grows up! Lol

I was literally just looking at ST41 and ST40 last night. Is the few mm wider disk really worth the extra money or is there a significant difference in caliper design between the two?

My stock non PP brakes have almost 57k on them so replacement time aka an excuse to upgrade is rapidly approaching
 

GTI Jake

Autocross Champion
Location
Charlotte, NC
Also the cost difference between solid and two piece rotors vs performance on a car that sees 99% street duty

I think I’d be more than satisfied with ST41 & solid rotors, but I’ve never upgraded to a BBK before
 

jmason

Go Kart Newbie
Location
Frederick, MD
I'm considering replacing my Brembo 330mm BBK with the Stoptech kit you discuss. The Stoptech pad is about 1/2 longer than the pads that fit the Brembo, which may help pad life. The lighter disk might help out too with a reduction in braking distance (less rotational inertia), although the replacement cost of the rotor vs. the Brembo is significantly higher. I'm also having an issue with the brake line coming in contact with my 17" Neuspeed wheels. The brake line can't be twisted to provide the needed clearance. The banjo fitting of the Stoptech should help out by providing 180 degree twist increments versus the 360 degree available with the Brembo.

At my last track weekend, I took a ride with an instructor in his late model stock Porsche. It is amazing how short the braking distance is in that car! Huge brakes and rear weight bias are the reasons. All the Porsches were able to significantly out-brake me. Just too much weight on the front wheels and, as you point out, not much help from the lightly loaded rears.
 

2015WhiteGTI

Go Kart Champion
My car wants to be like yours when it grows up! Lol

I was literally just looking at ST41 and ST40 last night. Is the few mm wider disk really worth the extra money or is there a significant difference in caliper design between the two?

My stock non PP brakes have almost 57k on them so replacement time aka an excuse to upgrade is rapidly approaching

The ST40 is a beefier caliper for sure. The ST41 caliper would possibly allow you to run the stock Austin's with no spacer.

Also the cost difference between solid and two piece rotors vs performance on a car that sees 99% street duty

I think I’d be more than satisfied with ST41 & solid rotors, but I’ve never upgraded to a BBK before

ST41 kit will more than likely be perfect for you.

For me, I have my comp license (SCCA) and drive my car extremely aggressively in the turns. So, I can really feel the difference between small changes in the chassis and braking. I can notice the difference between the stock Austins and the Volk (forged wheel deflects less under load and the steering input is more precise under load). That's the main reason I went with the ST40 and the two-piece rotors.
 

2015WhiteGTI

Go Kart Champion
I'm considering replacing my Brembo 330mm BBK with the Stoptech kit you discuss. The Stoptech pad is about 1/2 longer than the pads that fit the Brembo, which may help pad life. The lighter disk might help out too with a reduction in braking distance (less rotational inertia), although the replacement cost of the rotor vs. the Brembo is significantly higher. I'm also having an issue with the brake line coming in contact with my 17" Neuspeed wheels. The brake line can't be twisted to provide the needed clearance. The banjo fitting of the Stoptech should help out by providing 180 degree twist increments versus the 360 degree available with the Brembo.

At my last track weekend, I took a ride with an instructor in his late model stock Porsche. It is amazing how short the braking distance is in that car! Huge brakes and rear weight bias are the reasons. All the Porsches were able to significantly out-brake me. Just too much weight on the front wheels and, as you point out, not much help from the lightly loaded rears.

The fact that you're actually tracking your car would lead me to suggest the ST40 kit for you for sure. The rotors will last you longer than you think. A more aggressive pad will shorten your braking distances too (at the expense of rotor life). Also, don't get cross-drilled rotors for any track use. They eat your brakes. Years ago, they had a purpose to release the gas build-up from the pads. The new pads don't have that issue anymore. I usually run slotted at the most. We've run a full 12 hours on blank discs in an endurance race with zero issues (see pic).

These little GTI's do have an advantage in the weigh department. My 2015 S model comes in at under 3000lbs. with my Volks installed. That helps quite a bit in the tossability and braking. It's just a completely different driving style vs. a RWD car or even a rear engined car.
Yes, the Porsche brakes are phenomenal, but you're paying the price up front for that performance :D
 

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ErBall

Measurement Mogul
Location
Indiana
Car(s)
MQB A3
I had this kit on a mk6. It's all fun and games till you find out replacement rotor rings are nearly half the cost of the kit itself.
 

daujin_mk7

Go Kart Champion
Location
PA
Car(s)
2016 GTI DSG
Nice! Maybe ill see you driving around the area

Sent from my Pixel 2 using Tapatalk
 
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jmason

Go Kart Newbie
Location
Frederick, MD
It's all fun and games till you find out replacement rotor rings are nearly half the cost of the kit itself.

My point exactly! About 50% more than the Brembo.
 

2015WhiteGTI

Go Kart Champion
My point exactly! About 50% more than the Brembo.

Is that for the one-piece rotor from Brembo or two-piece?

I tried to find a 328mm two-piece replacement rotor for Brembo and could only find one for a Panoz and it was $475 each.
The Stoptech two-piece replacement rotor is $315 each.

TBH - I had my Stoptechs on my BMW for eight years with a ton of track time (about 20 track days per season) and over 50K miles total. I had to replace the front rotors once and the rears were the original. Had I found proper pads earlier on, they more than likely would have lasted even longer.
 

jmason

Go Kart Newbie
Location
Frederick, MD
Is that for the one-piece rotor from Brembo or two-piece?

One piece.

I tried to find a 328mm two-piece replacement rotor for Brembo and could only find one for a Panoz and it was $475 each.
The Stoptech two-piece replacement rotor is $315 each.

One piece Brembo rotors are $175 each.

ITBH - I had my Stoptechs on my BMW for eight years with a ton of track time (about 20 track days per season) and over 50K miles total. I had to replace the front rotors once and the rears were the original. Had I found proper pads earlier on, they more than likely would have lasted even longer.

My Brembo rotors show signed of surface cracking, both on cross-drilled and slotted. I don't use cross-drilled any more. Not wanting to be rejected at tech inspection for cracks in the rotor, I preemptively replaced them before I thought it might be a problem. Arguably, I replaced them too often/too soon.
 

2015WhiteGTI

Go Kart Champion
One piece.



One piece Brembo rotors are $175 each.



My Brembo rotors show signed of surface cracking, both on cross-drilled and slotted. I don't use cross-drilled any more. Not wanting to be rejected at tech inspection for cracks in the rotor, I preemptively replaced them before I thought it might be a problem. Arguably, I replaced them too often/too soon.

Stoptech one piece rotors are $175 each as well (slotted).
https://www.zeckhausen.com/catalog/product_info.php?cPath=515&products_id=16479
 

jmason

Go Kart Newbie
Location
Frederick, MD

2015WhiteGTI

Go Kart Champion
Thanks. Good to know. I could use those for street, put on the two piece rotors for track days.

You can't interchange between the two different rotor types. The two-piece is 3mm wider than the one-piece.
 

jmason

Go Kart Newbie
Location
Frederick, MD
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