Wheels & tyres for sprint racing

Wheels, Suspension, Brakes & Tyres questions and answers

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beavis
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Re: Wheels & tyres for sprint racing

Postby beavis » Wed Jun 11, 2014 11:32 pm

Ben MX5 wrote:1. Does this match your experience?
2. If I move to, say, an AD08R ...
3. If I'm going to get a second set of rims, what's the recommendation? ...
4. And finally tyre pressures....


1. No. Usually R tyres are harder to control than road tyres.
2. The AD08 is an awesome road tyre and will be superior to your Kumhos.
3. 15's are usually the diameter of choice. If you want to stay on stock rims, so be it. Width and weight are important, so buy a light rim which is as wide as your class will allow.
4. 40-45psi is too high. Expect around 34psi hot for a road tyre. I dont care about cold pressures.
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kazama
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Re: Wheels & tyres for sprint racing

Postby kazama » Thu Jun 12, 2014 9:53 am

ad08s would be a good choice. never heard a bad thing about them

over heated tyres are unnerving. good upgrade imo

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Re: Wheels & tyres for sprint racing

Postby rascal » Thu Jun 12, 2014 11:18 am

Ben MX5 wrote:Chatting away afterwards a few of the FFCC guys were strongly of the view that I should get type R tyres sooner rather than later. In their experience: on type R tyres, the car's easier to control, people have less offs and the tyres don't overheat and go off.
1. Does this match your experience?

Whilst there is an element of truth in this, its a false economy. Yes, the car will feel more predictable on R specs vs lesser tyres "at the same corner speeds", however the R specs will allow you to run much faster/quicker which means when you do exceed the tyres grip limits it will be at a much higher speed, which may be beyond your current skill level. eg, you need much better reflexes/skills to catch a slide at 120kmh than one at 80kmh. You are better off improving your skills first (using lesser tyres so you get to learn at an easier level) so that if/when you do go to R specs, you have a higher level of skill to match the higher level of grip.

eg, a formula 1 car has much better grip level than a mx5, but you wouldnt try to learn car control skills in a f1 car cos its levels are so high that when you exceed them your chances of catching it would be almost zero.

Ben MX5 wrote:2. If I move to, say, an AD08R (allowed in the standard class but still meant for the track) will I notice improvements along these lines?

You will notice immediate improvements in your lap times, but these will be solely down to the tyres and nothing to do with your abilities having improved.
Though if you are burning up the KU31s then are probably ready to jump to AD08s as these will serve you for a long time in the future. If you find much later on that you are being limited by the AD08s then you could move to R specs, as by then your skills would be up enough to do them justice.


Ben MX5 wrote:3. If I'm going to get a second set of rims, what's the recommendation? 15 or 16? How important are weight and width? Are we talking a second or a tenth of a second? I like the look of the standard 16's + their cheaper (and presumably won't break) but the savings are partly offset by paying more for tyres.

I would place more emphasis on tyre price than rim price. Even though the rims may be cheaper, you only buy them once, whereas tyres you will buy over and over again.
The weight and width differences would be measured in tenths not seconds.
imho, a second set is the way to go, and get 15s. 15x8 with a 205/50 is a good sweet spot, or if really serious and chasing that last tenth, you can go 15x9 with 225/45 which are probably the ultimate setup but comes with likely fitment issues that you'd need to deal with.

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Re: Wheels & tyres for sprint racing

Postby david_syd_au » Fri Jun 13, 2014 8:20 am

I agree with "rascal" that road tyres are more forgiving than R-specs in that when you push too far the result happens at a lower speed and should be easier to catch.
When I started doing track days, I deliberately stayed on road tyres for the first year, in my case KU36's, and built up experience and skills at track days and driver training days, before moving to R-specs.
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Re: Wheels & tyres for sprint racing

Postby Ben MX5 » Mon Jun 16, 2014 8:16 pm

Thanks again,

It's good to get some consensus - for a while there the more I tried to work it out the more confused I got.

-Ben
Stock 03 NB on AD08Rs
Broadford 1m 13.0s
Phillip Island 2m 05.2s
Sandown 1m 38.2s
Winton - short 1m 14.7s
Winton - long 1m 49.3s
Calder 1m 17.3s


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