Big brake kit question

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EarlGrey
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Big brake kit question

Post by EarlGrey » Sat Aug 19, 2017 10:52 pm

Hi everyone. So I have a question regarding big brake kits (as the title suggests). I am running 19" alloys with et 35 and my rear brakes need doing. Since getting these new wheels, I've been toying with the idea of big brakes.
The question is, could I convert the back without doing the fronts without any negative impact (as I had new front discs and pads less than 1000 miles ago) or should I do all four corners if I'm going to do this. Also, do any of you have recommendations for kits that won't break the bank?
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Re: Big brake kit question

Post by Rotary Potato » Sat Aug 19, 2017 11:07 pm

The back brakes don't really do as much as the front on an RX8, so from a functional point of view there's little point of putting bigger brakes on the rear.

If your looking at it from a purely asthetic point of view, then beauty is in the eye of the beholder ... you're writing the cheques, so do what you want.

You can fit huge dinner plate sized brakes on the front, with the back stock and the car manages ok ... so I can't see why the reverse wouldn't be true too.
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PeteH
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Re: Big brake kit question

Post by PeteH » Sat Aug 19, 2017 11:36 pm

Sorry, I have to disagree. The rear brakes do a fair bit. The rear brakes are already fairly big, and I go through rear pads quite quickly on the track. My calcs suggested the rears do at least 40% of the work at light to moderate braking. It's because the 8 has such a low centre of gravity, and such good weight distribution.

Putting big brakes only on the rear axle is a very dangerous thing to do. Please don't do it. You will direct more brake balance to the rear axle which, in heavy braking, will be like applying the handbrake. The car will be destabilised, and could easily spin.

Putting them on only the front is fine because early front locking is a stable condition, and the ABS can deal with it. But the same is very definitely not the case with just big rear brakes.
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Re: Big brake kit question

Post by EarlGrey » Sun Aug 20, 2017 12:42 am

Thanks for the advice.
I guess I'll stick with the stock size. Would the same be true of drilled/grooved disks with updated pads then? Change front and backs at the same time otherwise just stick to stock?
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Phil Bate
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Re: Big brake kit question

Post by Phil Bate » Sun Aug 20, 2017 1:09 am

For your purposes stick to the same type of pad front to back. The style of disk will make effectively no difference to the braking force.
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Re: Big brake kit question

Post by Rotary Potato » Sun Aug 20, 2017 7:55 am

PeteH wrote:Sorry, I have to disagree. The rear brakes do a fair bit. The rear brakes are already fairly big, and I go through rear pads quite quickly on the track. My calcs suggested the rears do at least 40% of the work at light to moderate braking. It's because the 8 has such a low centre of gravity, and such good weight distribution.

Putting big brakes only on the rear axle is a very dangerous thing to do. Please don't do it. You will direct more brake balance to the rear axle which, in heavy braking, will be like applying the handbrake. The car will be destabilised, and could easily spin.

Putting them on only the front is fine because early front locking is a stable condition, and the ABS can deal with it. But the same is very definitely not the case with just big rear brakes.
Thanks Pete.

I stand corrected.
Huw

2004 Velocity Red 231 - SatNav, parking sensors, sunroof, red/black interior, K&N Typhoon, Toyo backbox, f- :censored: -ked engine - bought Jun 2016 sold Oct 2016
2006 Black PZ - Rotary Revs full Bridgeport Gold rebuild - Toyosport decat - SAI delete - 585R coils - K&N air filter - purchased Oct 2016 - Engine rebuild Dec 2017

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