What actually is the deal with tyre pressures when you change the wheel size on your car, do you stick with the manufactures reccomendation??

is it to do with the size weight of the car, and should you keep the same pressures if you go from 16" wheels to 19"????

 

iv always ran 32psi in all my tyres then again iv never whent above 16s lol

 

yeah me too, although ive just been starting to think about it a bit more.

my mate has an rs4 with 19's and the manufacturers recommend 34 psi

i have just picked up a bm 320 with 18's and the tyre pressures are set to 26.5 psi

and i run 19's on my cossie and not really sure what to set them at, or if the bm's are at the right pressure.

 

I just stick to what Ford say.

 

The size of the wheel doesn't really effect it, its more down to the width and weight of the car.

I only run 20psi in my tyres on the civic, but they are very wide on a light car, it also has fairly large sidewalls as well, if they were small sidewalls I might want to run more pressure to stop them "hitting the rim".

 

As above, it's the weight... changing the profile of the tyre shouldn't make any difference.

 

20 psi is pretty low. They will wear more quickly!

 

thats what i was thinkin, and possibly overheat and blow-out

 

Yeah, wouldn't do much high speed stuff running that pressure. Would also be very wallowy turning into corners and as you say, would get hot quickly, becoming useless under hard driving!