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The mkiv Supra Owners Club

k sport brakes any good?


jsnlvxr

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I've been thinking the same the last few months.

After doing some research they are a lot better than they used to be by all accounts.

Some say the brake feel is better than the UK brakes, others have issues with getting them to fit under certain alloys due to their size.

Meant to be well built and it's a product of the US so I'd imagine quite good quality too.

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There's a myth that more pistons are better. In fact, so long as the caliper is stiff enough, and the pad and disc thermal capacity adequate to stop tapered pad wear, the fewer pistons the better. Each additional piston and seal adds pedal travel and operational lag. IMO there's no justification for 8 pots save the perceived pub banter effect. The front calipers on my Skyline are 4 pot, yet were deemed ideal to haul a Group C car down from 200 plus MPH repetitively, for 24 hours at a time.

 

Calipers should be judged by their stiffness under expansion forces from the pistons on the pads via the disc. This stiffness can degrade dramatically at high temperatures if aluminium alloys are used, as opposed to cast iron. The material used makes a huge difference and is the main reason proper race calipers are a lot dearer than a bling road car caliper. If the budget allows AP racing, Brembo or Alcon are much more real world performance orientated. From a matrials stiffness point of view drilling four dirty great bores in an alloy beam does bugger all good for its stiffness. 2 holes is much better!

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There's a myth that more pistons are better. In fact, so long as the caliper is stiff enough, and the pad and disc thermal capacity adequate to stop tapered pad wear, the fewer pistons the better. Each additional piston and seal adds pedal travel and operational lag. IMO there's no justification for 8 pots save the perceived pub banter effect. The front calipers on my Skyline are 4 pot, yet were deemed ideal to haul a Group C car down from 200 plus MPH repetitively, for 24 hours at a time.

 

Calipers should be judged by their stiffness under expansion forces from the pistons on the pads via the disc. This stiffness can degrade dramatically at high temperatures if aluminium alloys are used, as opposed to cast iron. The material used makes a huge difference and is the main reason proper race calipers are a lot dearer than a bling road car caliper. If the budget allows AP racing, Brembo or Alcon are much more real world performance orientated. From a matrials stiffness point of view drilling four dirty great bores in an alloy beam does bugger all good for its stiffness. 2 holes is much better!

 

And this man knows his stuff! So are the UK spec brakes made of good stuff for normal driving and track days then Chris?

 

(P.S. Tried to call you earlier reference something else, I'll try again later on)

 

Ive had them and they are very good brakes. Very well built. Brake feel is better that the uk spec brakes. They are made in Korea.

 

Ah didn't know they were made in Korea, every days a school day!

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I understand about the number of pistons etc isnt always better, I run 4 pot alcons with carbotech pads on my track astra and they rip your face off. Only reason im asking about the k sport is because they seem fair priced really. Thanks for all the advice though!

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UK front calipers are half cast iron, half aluminium alloy. They have enough pad area to be effective on track, and the stock discs have a lot of thermal mass, so with suitable pads and fluid they work well on track. their downside is the weight, but if you use lightweight discs they will need some form of forced air cooling into the eyes of the front discs. For the average track dayer they are fine as is with decent pads and fluid, and maybe braided hoses for a better pedal feel.

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I have them on my track car now for 3 years and on my last supra (Same kit) for 1 year and they have been fine so far.

As with anything braking is down to pad choice, fluid and tyres not just bigger discs and bigger calipers.

 

UK spec brakes have been proven on the track but IMO I found the feel awful.

 

I am looking to change my brakes from Ksport to AP Racing when I have the chance but this is mainly down to the fact that I may need to get hold of spare parts quickly and in my experience the lesser known brands usually have longer spares lead times, although with the Ksport kit I have yet to test that (they have not let me down at all).

 

I would say whacking on 8 pot on the fronts is going to bugger your brake balance, you may want to put UK rears on or at least at least upgrade the rears with one of the Ksport rear kits. No point making your front tyres do ALL the braking work, not only will you actually lose performance it could cause a nasty accident.

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I have the K-Sport 8pot 356mm fronts and 6pot 330mm rears. I find them a little 'relaxed' generally but with yellow stuff pads I'm reasonably happy with the performance on the track. Much better than the JSpec stock setup!

 

I will be getting Porterfield racing pads for the next track season though.

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I had UK brakes all round on mine and then went for KAD brakes all round. Personally I would have saved a lot of trouble and hassle had I simply stuck with the well proven UK setup.

 

For hardcore Track driving perhaps a decent set of Brembos or similar would be a better choice over the very well designed UK brakes.

 

imi

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Paul Whif runs AP on his race car and SteveL had KADS. Neither ever had any real problems and remember Steve did half a season of euro saloons which was wheel to wheel racing on slicks for half an hour or so at a time. I had lowly jspecs on my Supe but with Porterfield race pads they were quite impressive, if noisy at low speed and very dirty!

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l'll comment on the KAD brakes that I had. Bloody nightmare to fit as they were adapted for the supra not purpose built.

 

Not to mention the rear pads would chatter while driving - bloody annoying.

 

Amazes me how some of these namby Pamby companies think they can outsmart Toyota.

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In fairness race and aftermarket calipers and pads usually have no provision for anti rattle stuff,

so buyers need to expect pad squeal and pad rattle. My fast road pads now have wear indicators, and will

take stock anti rattle clips and anti squeal shims. Most full race pads won't (thicker backing plates).

 

 

Toyota, like all mainstream car companies, will spend a lot of time finding a compromise to give efficient braking

with near silent operation, but will not usually be considering race track usage or how caliper size affects aftermarket rim choice.

They will consider long term durability and good piston seal protection from the elements.

Race caliper designers consider beam stiffness, weight, heat paths, and usually do not give a stuff about noise or long term

durability with salt and grit about.

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I run UK spec brakes with race pads and custom floating AP discs, never had a problem.

 

If I were to change it would be for better pad choice and then I would look at an Alcon, AP or Brembo setup.

 

My car was the test / fit supra for Hi-Spec brakes many years ago, a mistake on my part as two hard laps on track and the brakes were totaled, they came straight off and stocks went back on, luckily as my car was used for the templates I didnt pay full price :D

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If people are able to do the maths for piston sizes, pad areas and disc swept diameters, and also fabricate fairly simple alumium alloy brackets, the race car parts sites have umpteen calipers available, new and used, that can be pressed into service. My GTS-t has huge 4 pot Group C Brembo calipers with endurance pad fitment (very thick quick release pads to last for long hours at race speeds in endurance racing), and Aston Martin rear Brembo calipers. I made my own brackets and bells, and used AP discs. Whilst the discs weren't, and aren't, cheap (I've got through six sets to date), the calipers were VERY cheap as they were considered oddball. Buying kits is straightforward, and they should just bolt on, although some posts here suggest people have had issues, but it's a very dear way to get upgraded brakes.

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After I changed to the Alcon monoblocks the pedal feel improved tremendously, I was no longer able to get any fade on the road at all and I also started to "challenge" the 255 front tyres :D

 

Some of that fade resistance may have been pad related to as I changed from Chris' fast road pads to a Carbotech XP8 compound but the improvement in feel was almost certainly because of the floating discs and the massively stiff Alcon caliper design.

 

Personally I would not change from UK to K-Sport or KAD unless I had weight saving in mind and had done the maths to check the aftermarket alternatives were not actually a downgrade in terms of outright stopping power.

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