Yokohama a539
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Discussion

analog_me

Original Poster:

287 posts

149 months

Saturday 5th October 2019
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Good morning all,

I decided to go for these tires as I was looking for a low grip but nice handling tire to enjoy the car on the road to the max without doing crazy speeds.
I have only done 25 miles on them and like them already.
I started at 18psi cold all round but the side walls were flexing and affecting the responsiveness of the car. I went up to 22psi hot(er) all round and seems much better. I do believe there is more potential to get out of them. What was the racers preference back in the days these where used on the classic graduates??
I know I can find out myself but would appreciate using the existing knowledge rather than reinventing the wheel.
The car is a stock k-series superlight on 175/60r13.
Thanks

Matt W

158 posts

258 months

Sunday 6th October 2019
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22psi hot is what I used in A539s when racing a Classic Grad over the past few seasons. I won the championship last year.

The thing that improves dry performance most is shaving the tread down to around 3.5mm. This could be worth around 2 seconds per lap!

analog_me

Original Poster:

287 posts

149 months

Sunday 6th October 2019
quotequote all
Hi Matt,

Many thanks for your reply,
Yes i can feel the blocks moving too much and understand that shaving them would improve things, especially the response of the tire to your commands.
I found 23 all round hot works relatively well,
What i want to get rid of is the flex of the side wall and i found that anything above 23 compromises grip where as anything less increases the movement of the sidewalls.
Also increasing pressure above 23 makes the breakaway too violent,
I will try 22psi for a bit longer next time, and compare side by side to the 23. unless my pressure gauge reads differently to yours, then for sure your suggestion is better than my finding.

In any case i found if you are smooth enough with your controls, both front and rear axles respond and loose grip more similarly to each other.


dhutch

17,388 posts

217 months

Tuesday 4th February 2020
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Using the same tyre and pressures on the Westfield, although I am on the slightly larger 185/60R13

Car is used for autotesting as well as fast road use, so much be on a list 1a tyre.


Daniel