Tire pressures

What is the mist optimal tire pressure for around 15 to 20 celcius.

What tires? 20 char…

1 Like

Need info on Tires and class. One rule of thumb you can use is to have hot pressures not read more than two psi above cold.


Its j125 X30 and i have a medium conpound

What brand of tire is it and what is the compound called? Usually they are named by a color or letter designation.

There are dozens of tires that could be called a “medium compound”.

The color is yellow and its a mg tire

MG Yellows your cold pressure should be between 7.5 psi - 9.5 psi depending on track conditions. Lower if it’s hotter, higher if it’s colder.

We typically stay around 8 - 9 for most conditions. Lower than 8 or higher than 9 would be for fairly extreme track conditions.

For the sake of complete info for new guy, define what Hot and Cold is, maybe.

Odd factoid: my summer pzeros have a very definite “cold” point. At 45 deg F, they start doing the “acorn” noise when turning wheel parked. This is when you know you have to be careful, really careful.

1 Like

Cold = before the session
Hot = after the session

Set your pressures before the tire is warmed up, check them after the session. You’ll want 2-3 psi of pressure increase usually, maybe more or less if you’re running nitrogen vs. air.

I mean ambient. If I read you correctly, if it’s hotter than X you deflate a bit, if it’s colder than Y, you increase pressure.

In general what’s considered “normal” operating ambient? 60-90f?

I think that’s overthinking it too much. You have a range of ambient temps you normally race in and a range of pressures to use. Fairly simple, use the higher pressure when it’s colder out, use the lower pressure when it’s hot out.

We’re talking a range of 2 psi, pretty hard to screw it up too badly.

Yeah I guess so. He can always ask around for general pressure range at his track.