ZZR pressures?
Discussion
It's down to the lightness of the car ...like the 55 ft lbs torque setting on wheel nuts ...
I've just reduced my tyre pressures to 20 all round cold on a CSR that I'm getting to know ... I had 23 all round because the recommendation felt too low and the tyres were still cold after a good drive !
It still gripped, but I want to see the whole tyre warm and wearing across the whole width.
Of course at the moment I'm not trying hard enough
I've just reduced my tyre pressures to 20 all round cold on a CSR that I'm getting to know ... I had 23 all round because the recommendation felt too low and the tyres were still cold after a good drive !
It still gripped, but I want to see the whole tyre warm and wearing across the whole width.
Of course at the moment I'm not trying hard enough
I had a conversation last week with a seven owner at Cadwell who was running ZZR's, he informed that on the first set he used the front tyre tread stripped off, thinking it was a bad batch he sent them back to Avon who asked what pressure had he used when he told them 17/18 cold they replied that this was far to low and was the reason for the tyres stripping and they had received other ZZR stripped tyres running on similar pressures.
They recommended 25/26 cold and 4 degrees camber, he's now running this set up and the tyres have even wear and good performance.
Not a personal view or recommendation just sharing another's experience.
They recommended 25/26 cold and 4 degrees camber, he's now running this set up and the tyres have even wear and good performance.
Not a personal view or recommendation just sharing another's experience.
This is interesting.
Track work is at a different level from roadwork ...
For track I have Cayman GT4 running on MPSCup2's and my target pressure with them is 30psi at the end of two cooling down laps. I don't mind seeing 32psi or even 33psi, but at 35psi they are ballooning and losing grip ...
Over the warming up laps I will take out 10 to 12 psi (absolute max) ... but would not dream of starting at 20psi ...
But it is only by softening the tyre that flex in the tyre wall generates the heat required to make the tread compound really grip ...
???
Track work is at a different level from roadwork ...
For track I have Cayman GT4 running on MPSCup2's and my target pressure with them is 30psi at the end of two cooling down laps. I don't mind seeing 32psi or even 33psi, but at 35psi they are ballooning and losing grip ...
Over the warming up laps I will take out 10 to 12 psi (absolute max) ... but would not dream of starting at 20psi ...
But it is only by softening the tyre that flex in the tyre wall generates the heat required to make the tread compound really grip ...
???
Darumvej said:
I had a conversation last week with a seven owner at Cadwell who was running ZZR's, he informed that on the first set he used the front tyre tread stripped off, thinking it was a bad batch he sent them back to Avon who asked what pressure had he used when he told them 17/18 cold they replied that this was far to low and was the reason for the tyres stripping and they had received other ZZR stripped tyres running on similar pressures.
They recommended 25/26 cold and 4 degrees camber, he's now running this set up and the tyres have even wear and good performance.
Not a personal view or recommendation just sharing another's experience.
A pyrometer (if using the car on track) will give you the answers you need to give a slight temp gradient over the time (and also allow you to accurately set camber). If you start to nail a treaded tyre before the rubber has had a chance to warm up, you can cold tear it, but stripping the outer layer seems to be a very odd phenomenon. The change in guidance of circa 8psi / 0.5bar seems a very large jump given the tyres have been around for a while.They recommended 25/26 cold and 4 degrees camber, he's now running this set up and the tyres have even wear and good performance.
Not a personal view or recommendation just sharing another's experience.
I run ZZRs on the road on my SLR, and tend to start with the cold pressures around 18psi. As already mentioned, it's hard to get sufficient heat in the tyre on the road unless you want to be in prison/hospital
As above. Get a tyre pyrometer and work out for your own setup what the optimum pressure is. Its very easy.. immediately when coming off track, measure the temperature across the tyre. You're looking for a nice gradient, rather than the centre being significantly hotter or colder than the shoulders.
I would only take advice (even from the manufacturer) as a general starting point. Your car, its weight, setup (especially camber), track and driving style will all have an impact on the correct hot pressure.
Be careful though.. If anyone sees you doing this they'll assume that you're taking the track day waaaay to seriously!
I would only take advice (even from the manufacturer) as a general starting point. Your car, its weight, setup (especially camber), track and driving style will all have an impact on the correct hot pressure.
Be careful though.. If anyone sees you doing this they'll assume that you're taking the track day waaaay to seriously!
Edited by mharris on Monday 23 April 12:09
ChrisW. said:
Over the warming up laps I will take out 10 to 12 psi (absolute max) ... but would not dream of starting at 20psi ...
The requirements for a 500kgs Caterham are vastly different from a 1T+ car. Starting point for trackday stuff for CR500's was always around 18psi cold for me. Haven't played with the ZZ's much but would tend to start in the same ballpark....though advice above seems to be to start higher for cold @ 22-24 ?
ChrisW. said:
I've just had to replace two 60% worn CR500's (to match the good CR500's on the front) because the previous owner ran the tyres with too much pressure leaving 4mm on the outer edge and 1.2mm in the centre ...
I wil try not to repeat this !
What pressure was the previous owner using please?I wil try not to repeat this !
Amris said:
For me it depends on the track and conditions. If its dry I generically run the ZZR's at 22 hot (can be as little as 13 cold), and the ZZS a little warmer around 24 hot.
If its wet i jack them up to 30PSI to get more traction!
I found the 24 hot about right for the ZZS. Any higher and my car turned into an uncontrollable mess. Understeer followed by oversteer. I thought something was broken!If its wet i jack them up to 30PSI to get more traction!
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