Big Brake Kit

[FSilva]

Hello.

Just wanted to enquire about a certain BBK for my car, the Cupra 300. On the supplier website, the attached kit doesn’t show on the drop down menu, only the smaller discs (355mm). However, on ProgressiveParts, apparently 380mm is now suitable for my car. Upon cross referencing, 380mm also fits MK7 Golf R so surely it stands to reason that it should also fit the Cupra?

As a side question are floating discs and vented discs interchangeable provided they are the same sizing? Floatings cost a fortune but I cannot find big vented discs in a kit.

 

[tracktoy]

I can confirm my 280 supports 380 BBK by Revo (Alcon) https://www.akstuning.co.uk/shop/ho...r_colour-red/1417-revo_disc_size-380mm_x_32mm.

But you need to ensure you wheels will support this size of kit (I don't use stock wheels).

Cant answer you second question but i can confirm on heavy use on the track these disk's work extremely well, to which end I have to ask why do you want the big brake kit is it just for road use, if so I would suggest its overkill.

I would also suggest you get some Audi Brake ducts and its a know issue of the MQB Platform with lack of cold air to the disks.

 

[FSilva]

I can confirm my 280 supports 380 BBK by Revo (Alcon) https://www.akstuning.co.uk/shop/ho...r_colour-red/1417-revo_disc_size-380mm_x_32mm.

But you need to ensure you wheels will support this size of kit (I don't use stock wheels).

Cant answer you second question but i can confirm on heavy use on the track these disk's work extremely well, to which end I have to ask why do you want the big brake kit is it just for road use, if so I would suggest its overkill.

I would also suggest you get some Audi Brake ducts and its a know issue of the MQB Platform with lack of cold air to the disks.

Thanks for the response! That actually gives me some hope then! Car is fast road use. Currently unable to do track days because I’m louder than 105 decibels. Last check at Cadwell was 104.7 mainly thanks to the slow throttle and 4 thousand rev limit on neutral

Already got the brake ducts and 19 inch Japan Racing alloys. Car is ready to roll to almost 500bhp and 600nm. Other than full body bushings or brakes, a lot has been done to the car including the most recent engine rebuild.

 

[nd-photo.nl]

Usually its not only wheel size, but also spoke design (so they dont scrape against the bigger caliper)

[edit]
I made a video a while back when I upgraded from 360mm to 390mm on my Mercedes CLS55 (Brembo 8 Pots calipers) in the stock 19mm CLS55 wheels. It can be a tight fit!

 

[FSilva]

Usually its not only wheel size, but also spoke design (so they dont scrape against the bigger caliper)

The current offset of the alloys matched my previous OEM alloys with 8mm spacers. Gave the spaces to my mate for his K1 and then he cleared his Brembos so can always buy some. Some hub centric ones of 3-7mm should save the day.

 

[FSilva]

I made a video a while back when I upgraded from 360mm to 390mm on my Mercedes CLS55 (Brembo 8 Pots calipers) in the stock 19mm CLS55 wheels. It can be a tight fit!

Oh wow!!! That’s impressive! Not gonna lie, I cannot contain my laughter at just how tight that is with 8 pots! I wonder if I’ll be able to get a barrel brush between the caliper and the barrel or if I’ll just have a bronze barrel that’s clean except a small black section of dust and dirt

 

[RUM4MO]

Just move the car by 1/2 a wheel rotation and then clean the 2 or 4 "still dirty" areas on the wheel barrels, I have to do that on both our cars when they have their "one size down" winter wheels+tyres on.

 

[FSilva]

Just move the car by 1/2 a wheel rotation and then clean the 2 or 4 "still dirty" areas on the wheel barrels, I have to do that on both our cars when they have their "one size down" winter wheels+tyres on.

Yep, think those 380mm BBK will have to be my next project. Not looking forward to getting to all that brake dust on bronze alloys. Currently need a new radiator as it’s cracked again and need to remove my APR PCV to open it up and apply new rings and gasket as it’s got a slow oil leak

 

[nd-photo.nl]

I switched from normal pads to ATE Ceramic, and it reduces dust with 90%, its crazy. For normal day to day usage its a proven combo, how they hold up with track usage, I cant tell you unfortunately.

 

[tracktoy]

This article seems to be fairly balanced view on the various brake pad types https://carroar.com/ceramic-brake-pads-pros-cons/ I personally have no experience of Ceramic but if this article is correct then disks may suffer if you are out on the track a lot.

 

[nd-photo.nl]

Small addition, they lack initial bite compared to a traditional pad, but thats about the only downside I can think of with my driving (style). The braking is more linear though.

 

[SuperV8]

As a side question are floating discs and vented discs interchangeable provided they are the same sizing? Floatings cost a fortune but I cannot find big vented discs in a kit.

If floating discs are the same dimensions as the standard disc there is no reason why they would not fit.

I would however suggest being honest with your use case. Floating discs have an elongated mounting hole, so as the disc friction surface expands due to temperature it is free to do so, rather than being constrained by the bell/top hat. These elongated holes need to be very tight tolerance to allow radial movement but not have any play otherwise they can rattle. On a race car this is not a problem, but on a road car probably not acceptable.

I would also carefully consider which caliper you pick, to ensure there are sensible pad options available, some racing calipers are limited in what pads are available locking you in to having to buy expensive 'racing' pads as a wearing item!

I would look at the 370x32mm performance pack front brake for a road car. Caliper & disc is shared with the earlier Audi TTRS.
#edit# these discs are bi-metallic, with an alloy bell & pinned rotor, so lighter and better at thermal expansion than standard full cast iron disc, but cheaper than a fully floating disc and no rattle. There are also aftermarket versions of these discs and pads.

 

[FSilva]

I would also carefully consider which caliper you pick, to ensure there are sensible pad options available, some racing calipers are limited in what pads are available locking you in to having to buy expensive 'racing' pads as a wearing item!

Lovely response, I appreciate it! I did see those floating discs that are in effect, one piece. I guess the concept of the points loosening up and rattling wouldn’t be an issue.

In regards to the caliper choice, it’s one of the reasons I was looking at EBC as my mate swears on the RPX pads for his Brembo calipers on the K1. However, I shall be consulting with Jabbasport for advice in this sector as they race a MK7 Golf so will have great knowledge

 

[SuperV8]

Lovely response, I appreciate it! I did see those floating discs that are in effect, one piece. I guess the concept of the points loosening up and rattling wouldn’t be an issue.

In regards to the caliper choice, it’s one of the reasons I was looking at EBC as my mate swears on the RPX pads for his Brembo calipers on the K1. However, I shall be consulting with Jabbasport for advice in this sector as they race a MK7 Golf so will have great knowledge

Race cars, and road cars have very different requirements for their brake systems, like they do for their tyres! You wouldn't want to use track optimised/race tyres in the cold and rain. Similar compromises for your brakes. Like I said - consider and be honest with your use case?

Don't forget your rear axle brakes, to keep the car nicely balanced.

Close up showing the slot and bobbin, the sides of which need very close tolerance. Corrosion/salt can ruin this close tolerance. Not a problem on a race car where you are frequently servicing your brakes and there would be no salt.

RP-X pads are NOT road legal to use in the UK or EU.

 

[FSilva]

Race cars, and road cars have very different requirements for their brake systems, like they do for their tyres! You wouldn't want to use track optimised/race tyres in the cold and rain. Similar compromises for your brakes. Like I said - consider and be honest with your use case?

Don't forget your rear axle brakes, to keep the car nicely balanced.

Close up showing the slot and bobbin, the sides of which need very close tolerance. Corrosion/salt can ruin this close tolerance. Not a problem on a race car where you are frequently servicing your brakes and there would be no salt.
View attachment 53575

RP-X pads are NOT road legal to use in the UK or EU.
View attachment 53576

Does anyone actually check “not road legal” items? I have plenty of them and never had an issue, even when stopped by police…. The Cupra is hardly on the road anyways as that’s a summer car but should be making its way to some local tracks once I get a resonator installed in. Snetterton and Donington have to be done this year!

I can tell you now, hand on heart, those bobbins would annoy me if they started rattling. Definitely can see why it would need high tolerance and frequent checks. Not something to install and simply forget about it.

 

[SuperV8]

Does anyone actually check “not road legal” items? I have plenty of them and never had an issue, even when stopped by police…. The Cupra is hardly on the road anyways as that’s a summer car but should be making its way to some local tracks once I get a resonator installed in. Snetterton and Donington have to be done this year!

I can tell you now, hand on heart, those bobbins would annoy me if they started rattling. Definitely can see why it would need high tolerance and frequent checks. Not something to install and simply forget about it.

The only time I would think anyone will check would be (lets cross our fingers!) if you are in a serious accident - which is the exact time when you want your car 100% roadworthy and you don't want your insurance void for any non-legal car parts!

I know very unlikely, but also could be very serious consequences - I can't say on a public forum, "yea its fine fitting those pad" when I know they are NOT legal.