Put 32 in mine a few weeks back and noticed this last weekend it was a bit bouncy a high speeds. Forgot to take the readings but as it was 91 degrees here for 2 days, would that effect the pressure bearing in mind air expands in heat

 

What should the tyre pressures be ? (noth back and front )

 

Mine are 32psi but some people like 34psi

 

ambient temp do affect tyre pressures and I posted about this in my Europe tour thread. I would adjust them back to 32 on a cold reading. I am no expert about this but it made sense to me when away and it worked as my car was exactly as you described it.

 

ambient temp makes a big difference

 

I don't have "cold" readings as such. The ambient temperature is high at the moment - in the 40s - and as the tarmac can fry an egg, the shortest of journeys heats the tyres up tons.

So... at the nearest garage a couple of Ks away I put 36 fronts & 38 rears (Michelins). Seems fine.

 

I also noticed this at the weekend.

Did the usual checks, and noticed they were 34 all round, where as I always run them at 32. Ambient temperature has quite an effect.

 

I was thinking this the other day when adjusting the pressures on my S.

I run Goodyear Eagle F1s and generally run them at 34psi cold (to counter the slightly softer sidewall).

After a pretty quick run last Friday (it was scorching in the SE), I stopped at my local Shell garage and checked them using their pump/gauge and they were reading ~ 40psi!

Is there a generally accepted correct ambient temperature when manufacturers are quoting tyre pressures?

Surely there's a market for a pressure gauge that measure the temp of the air too and adjusts accordingly?

 

You'd also have to measure the humidity and make up of the air within the tyre.