Tyre pressure Yokohama A048

[bher]

As in the title, what is the best pressure for the A048, on the dry and on the wet? mainly for track use...

[lawrence5]

24/26 (cold) Road this time of year. The 135R Owner's Handbook Supplement says 26/28 (cold). Track lose 1-4psi depending on weather....

[randy]

On the road something like 23/25 plus of minus a couple of pri will be fine. That said 48's are pants on the road and personally I wouldn't bother with them. On track, where they are bloody good, you want to go for something like 26/28 hot which will likely translate to circa 18/20 cold but the cold pressure is irrelevant - always take the hot pressures as soon as the car comes off the circuit.

[bher]

randy said:

the cold pressure is irrelevant - always take the hot pressures as soon as the car comes off the circuit.

Thanks this is very interesting for me, because I use to only mesure Temp when cold.
Could you be more precise, please? Do you inflate/deflate with cold air when pressure is not correct just exiting the track?? Do you then mesure the pressure when cold to reproduce it next time? Do you change regarding the external temp/ track temp?
My driving level does probably not require such fine tuning but I like this rationnal aspect of track days.
Ben

>> Edited by bher on Thursday 26th January 11:06

[shangani]

As Randy said, you get the tyres warm, drive off the circuit and immediately check the pressures. Generally you will be deflating to get the desired pressure. When you go home - ie colder tyres for road use, you inflate back to the recommended pressures.

[RobM77]

Yes, the standard way to check pressures on a car is from cold. However, when tweaking tyres pressures or engaging in setup related activities on the track (such as "what pressures whould I run at?", what is really important is the pressures that the car actually has as it is running round the track. For instance, I have the tyre pressures on my racing Metro (which runs 48Rs) set to be 30psi all round when hot. I know that when the car cools down this equates to 25/26 F/R from cold. This is reliable because I always push the car to the exactly same degree on track. On the road, you will push differently every time you drive (and nowhere near as much), so hot tyre pressures don't tend to tell you very much. Manufacturer's pressures are always given as cold.