SM Big Brake Kit - QP V Sport GT S

Devonboy

Member
Messages
1,066
I visited @Gazcw who contacted me to sell me the SM Big Brake kit and even fitted it - what a decent chap. First off, the QP V S he is selling looks cracking - it deserves to go to a good home.

Secondly, he was pumped up on anti-histamines to prevent any hives from my red calipers - thank god for modern medicine. I have been following the SM kit and thanks to @Zep who remembered my interest. The two recognized shortcomings in the QP V were "glassy" steering (which I don't mind) and poor brakes. These discs were trialed by @rossm and then sold to GACW and have around 2000 miles on them. They came with Stoptech Street pads.

I have always felt that the standard brake setup on the QP was sub par. The pedal feel has never been firm and always long - even after a brake service and fluid change. This meant I was always braking earlier than I would in say our BMW 520 and the brake feel was not consistent. Too many times I have pressed the pedal and felt so little happen, that it has caused a little adrenalin spike before the long final shove to get the car to slow, and even then it did so begrudgingly, and in a lump. In essence it was a lot of brake, mainly at once and at the bottom of the pedal, with a variable response in stopping power as you got there!

The QP is a heavy car and having read rossm's review I had made my mind up to upgrade from the standard 360mm disks to the SM Big Brake kit when my discs next needed changing. The upgraded brake kit consists of larger 380mm disks with aluminum bells which reduces un-sprung weight despite the larger disk diameter - really noticeable when you lift them, and C hook grooves. You also get a pair of nicely milled brackets / spacers to offset the calipers for disk clearance, and all the mounting hardware required. Rossm chose the Stoptech street performance pads from Balance Motorsport (£163) as he thought they should handle a larger heat range without losing cold bite better than Brembo pads - time will tell on that one! The kit is similar to the below (mine came with some nicer black caliper spacer bars)

87012

The upgraded discs look great and fill the wheel space much more than the standard discs and those red calipers......well its the only way to go!

87013

87014

Please note this was before the application of brake cleaner!

So what is the verdict? The pads give good bite from cold, no squealing and it is much easier to modulate the brake pedal. The response starts higher up the pedal and it increases much more consistently with further travel, this gave me an immediate increase in confidence through the country lanes on the way home. The response is fairly linear in although naturally gets more progressive as you reach the end of the pedal travel. I drove 55 miles home and never experience that mild sense panic when the braking surprises you by arriving later than expected. I could detect no drop off in performance even when hot (and I went through quite a few cycles as I played around with the new brakes) and there was no loss of performance or any sense of braking imbalance with the oversized front setup. To be fair, I didn't really notice the difference from the saving in the un-sprung weight either.

This wont give you the modern braking of a German car, but the biggest improvement is in the feel and consistency (and I suspect stopping distance but I haven't measured that!) this new package provides good feedback through the pedal and a much more trustworthy response which just inspires much more confidence. This upgraded kit delivers brakes that are predictable and consistent so you can learn and adapt to the expected braking distances and drive more confidently.

This is definitely a worthwhile upgrade and I have been told by a previous reviewer that it was a no cost update on his insurance - something I will confirm with my insurer (Admiral).

So another great upgrade from SM - and great value compared to OEM
 
Last edited:

Gazcw

Member
Messages
4,534
I visited @Gazcw who contacted me to sell me the SM Big Brake kit and even fitted it - what a decent chap. First off, the QP V S he is selling looks cracking - it deserves to go to a good home.

Secondly, he was pumped up on anti-histamines to prevent any hives from my red calipers - thank god for modern medicine. I have been following the SM kit and thanks to @Zep who remembered my interest. The two recognized shortcomings in the QP V were "glassy" steering (which I don't mind) and poor brakes. These discs were trialed by @rossm and then sold to GACW and have around 2000 miles on them. They came with Stoptech Street pads.

I have always felt that the standard brake setup on the QP was sub par. The pedal feel has never been firm and always long - even after a brake service and fluid change. This meant I was always braking earlier than I would in say our BMW 520 and the brake feel was not consistent. Too many times I have pressed the pedal and felt so little happen, that it has caused a little adrenalin spike before the long final shove to get the car to slow, and even then it did begrudgingly and in a lump. In essence it was a lot of brake, mainly at once and at the bottom of the pedal, with a variable response in stopping power as you got there!

The QP is a heavy car and having read rossm's review, I had made my mind up to upgrade from the standard 360mm disks to the SM Big Brake kit when my discs needed changing. The upgraded brake kit consists of larger 380mm disks with aluminum bells which reduced un-sprung weight despite the larger disk diameter - really noticeable when you lift them, and C hook grooves. You also get a pair of nicely milled brackets / spacers to offset the calipers for disk clearance, and all the mounting hardware required. Rossm chose the Stoptech street performance pads from Balance Motorsport (£163 delivered) as he thought they should handle a larger heat range without losing cold bite better than Brembo pads - time will tell on that one! The kit is similar to the below (mine came with some nicer black caliper spacer bars)

View attachment 87012

The upgraded discs look great and fill the wheel space much more than the standard discs and those red calipers......well its the only way to go!

View attachment 87013

View attachment 87014

Please note this was before the application of brake cleaner!

So what is the verdict? The pads give good bite from cold, no squealing and much easier to modulate the brake pedal. The response starts higher up the pedal and it increases much more consistently with further travel, this gave me an immediate increase in confidence through the country lanes on the way home. The response is fairly linear in although naturally gets more progressive as you reach the end of the pedal. I drove 55 miles home and never experience that mild sense panic when the braking surprises you by arriving later than expected. I could detect no drop off in performance even when hot (and I went through quite a few cycles as I played around with the new brakes) and there was no loss of performance or sense of braking imbalance with the oversized front setup. To be fair, I didn't really notice the difference from the saving in the un-sprung weight either.

So the verdict? This wont give you the modern braking of a German car, but the biggest improvement is in the feel and consistency (and I suspect stopping distance but I haven't measured that!) this new package provides good feedback through the pedal and a much more trustworthy response which just inspires much more confidence. This upgraded kit delivers brakes that are predictable and consistent so you can learn and adapt to the expected braking distances and drive more confidently.

This is definitely a worthwhile upgrade and I have been told by a previous reviewer that it was a no cost update on his insurance - something I will confirm with my insurer (Admiral).

So another great upgrade from SM!
Currently sat in bath of bleach to remove any redness. I will be using it on my eyes soon too.
Being used with red calipers has seriously degraded the street cred of those discs and they are now worthless.
Glad you like them. I missed them on the way down to SI and back yesterday.
Good luck with Admiral, they would not insure me for any modifications.
 

Devonboy

Member
Messages
1,066
Just to confirm - with Admiral - this counts as a modification, uprated brakes made no difference to my premium - just a policy amendment fee.
 

Devonboy

Member
Messages
1,066
Currently sat in bath of bleach to remove any redness. I will be using it on my eyes soon too.
Being used with red calipers has seriously degraded the street cred of those discs and they are now worthless.
Glad you like them. I missed them on the way down to SI and back yesterday.
Good luck with Admiral, they would not insure me for any modifications.
Admiral did tell me that they didn't like your Yellow Calipers apparently :):):)
 

Zep

Moderator
Messages
6,604
I visited @Gazcw who contacted me to sell me the SM Big Brake kit and even fitted it - what a decent chap. First off, the QP V S he is selling looks cracking - it deserves to go to a good home.

Secondly, he was pumped up on anti-histamines to prevent any hives from my red calipers - thank god for modern medicine. I have been following the SM kit and thanks to @Zep who remembered my interest. The two recognized shortcomings in the QP V were "glassy" steering (which I don't mind) and poor brakes. These discs were trialed by @rossm and then sold to GACW and have around 2000 miles on them. They came with Stoptech Street pads.

I have always felt that the standard brake setup on the QP was sub par. The pedal feel has never been firm and always long - even after a brake service and fluid change. This meant I was always braking earlier than I would in say our BMW 520 and the brake feel was not consistent. Too many times I have pressed the pedal and felt so little happen, that it has caused a little adrenalin spike before the long final shove to get the car to slow, and even then it did begrudgingly and in a lump. In essence it was a lot of brake, mainly at once and at the bottom of the pedal, with a variable response in stopping power as you got there!

The QP is a heavy car and having read rossm's review, I had made my mind up to upgrade from the standard 360mm disks to the SM Big Brake kit when my discs needed changing. The upgraded brake kit consists of larger 380mm disks with aluminum bells which reduced un-sprung weight despite the larger disk diameter - really noticeable when you lift them, and C hook grooves. You also get a pair of nicely milled brackets / spacers to offset the calipers for disk clearance, and all the mounting hardware required. Rossm chose the Stoptech street performance pads from Balance Motorsport (£163 delivered) as he thought they should handle a larger heat range without losing cold bite better than Brembo pads - time will tell on that one! The kit is similar to the below (mine came with some nicer black caliper spacer bars)

View attachment 87012

The upgraded discs look great and fill the wheel space much more than the standard discs and those red calipers......well its the only way to go!

View attachment 87013

View attachment 87014

Please note this was before the application of brake cleaner!

So what is the verdict? The pads give good bite from cold, no squealing and much easier to modulate the brake pedal. The response starts higher up the pedal and it increases much more consistently with further travel, this gave me an immediate increase in confidence through the country lanes on the way home. The response is fairly linear in although naturally gets more progressive as you reach the end of the pedal. I drove 55 miles home and never experience that mild sense panic when the braking surprises you by arriving later than expected. I could detect no drop off in performance even when hot (and I went through quite a few cycles as I played around with the new brakes) and there was no loss of performance or sense of braking imbalance with the oversized front setup. To be fair, I didn't really notice the difference from the saving in the un-sprung weight either.

So the verdict? This wont give you the modern braking of a German car, but the biggest improvement is in the feel and consistency (and I suspect stopping distance but I haven't measured that!) this new package provides good feedback through the pedal and a much more trustworthy response which just inspires much more confidence. This upgraded kit delivers brakes that are predictable and consistent so you can learn and adapt to the expected braking distances and drive more confidently.

This is definitely a worthwhile upgrade and I have been told by a previous reviewer that it was a no cost update on his insurance - something I will confirm with my insurer (Admiral).

So another great upgrade from SM!
Glad you like them, the feedback to date has been totally positive.

I agree with you, the pedal feel and progression is night and day to standard and makes the extra braking easier to use.
 
Last edited:

Gazcw

Member
Messages
4,534
How much does this cost?
It's not what they cost. It's the confidence they give you and the safety of stopping when you needed to. A side by side stopping distance test from 70 would be interesting. Carbons v 380mm v 360mm.
 

paul kenyon

Junior Member
Messages
23
It's not what they cost. It's the confidence they give you and the safety of stopping when you needed to. A side by side stopping distance test from 70 would be interesting. Carbons v 380mm v 360mm.
So if my priority is the best driving position available I should buy a McLaren F1 and ignore the fact I'm £10m short? :--)

I agree the brakes aren't the best on the QP but I'm sure most people would weigh up the best value options before deciding which way to go
 

Aeroresh

New Member
Messages
19
tbf the standard brakes on the QP (both 4 and 6pot calipers) are shocking compared with anything German. Its like the on-paper spec looks amazing but we've been cat-fished :oops:. If these inspire confidence its only a good thing
 

Gazcw

Member
Messages
4,534
So if my priority is the best driving position available I should buy a McLaren F1 and ignore the fact I'm £10m short? :--)

I agree the brakes aren't the best on the QP but I'm sure most people would weigh up the best value options before deciding which way to go
Agreed, but if you want the confidence and safety driving these cars as they were designed and the cost is acceptable to you then these are the way to go. If you are happy with the 360mm oem discs or you don't want to spend £1600ish on upgrading then switching to Zeps 360 alternative removes the dual cast issues and is more cost effective too.
 

ChrissGT

Member
Messages
287
Zep prices are quite a bit better compared to other 380mm big brake upgrades!

And i cant wait to put 360mm brakes on my 4.2. The 330mm brakes dont really let you do any late breaking :eek:
 
Reactions: Zep

Gazcw

Member
Messages
4,534
Zep prices are quite a bit better compared to other 380mm big brake upgrades!

And i cant wait to put 360mm brakes on my 4.2. The 330mm brakes dont really let you do any late breaking :eek:
I think no braking can be classified as late....
 

Felonious Crud

Moderator
Staff member
Messages
17,322
I think no braking can be classified as late....
As could potentially the driver, in extreme circumstances.

I'd have jumped at these on my GTS, which had **** brakes. The FD discs and yellow-stuff pads, which I upgraded to, improved things tremendously, but they were still bloody awful compared to any other car ever.
 

Devonboy

Member
Messages
1,066
As could potentially the driver, in extreme circumstances.

I'd have jumped at these on my GTS, which had **** brakes. The FD discs and yellow-stuff pads, which I upgraded to, improved things tremendously, but they were still bloody awful compared to any other car ever.
As could potentially the driver, in extreme circumstances.

I'd have jumped at these on my GTS, which had **** brakes. The FD discs and yellow-stuff pads, which I upgraded to, improved things tremendously, but they were still bloody awful compared to any other car ever.
I wonder if Zep has some 8 pot calipers on the way (all colours except yellow) as that is probably what is needed to get to nirvana. I would be interested to hear if anyone has done the full FD big brake upgrade with the 8 pots....but to be fair the FD kit is expensive!
 

Zep

Moderator
Messages
6,604
This is where it all gets a bit interesting. If you don’t change the master cylinder, you have to keep the same piston area in the caliper, or you have an issue with pedal travel, so the only benefit from a 8 pot caliper is increased pad area, not really something there is a massive issue with. To me, the difference to a German is pedal pressure, there is more servo assistance which gives the feel of more initial bite.

Almost anything is possible, 380mm is the limit for the standard caliper in terms of adaption, but with a different caliper 400mm would be possible, but would need a more complex mounting bracket and attention to wheel clearance and would probably be at least another £2k. But happy to do it if there is the appetite.