NOMADICISTA

My tires say 120 psi pressure. The guy at the tire shop only put in 100. He says the pressure will get to 120 when the tires warm up while driving.

Should they be filled to 120 psi while cold?

Or is the tire guy correct about only putting in 100 psi?

Depending on how warm it is he'll be "sort of" correct.

The tire pressure you see on your tires is the maximum fill level. This is especially crucial in the summer because the ambient heat, surface temperature of the asphalt and the friction temperature of your tires running down the road all play a part in causing tire pressure to build.

You aren't carrying a heavy load and you also aren't hauling people around or driving long distances. From what I've seen of the weather it's been warm where you are but hasn't been in the 90's yet.

I'm concerned about him leaving your tires 20 psi down since it isn't really hot out and you won't be driving thousands of miles.

Your tires should say (on the sidewall, close to the wheel) what the recommended cold pressure should be for your tires.

Running them too low can cause excessive heat build-up leading to blow-outs and or brake issues, ask any trucker.

FWIW: while I've never checked on TWE, my van tire pressure rises about 2.5 psi from cold to warmed up (215/70r15's).

I run mine at 100psi. They ride good at that pressure and they don't get too hot.
If I drive for an hour on a hot day, then put my hand on the tread of each tire they are never too hot.
If you can't leave your hand on the tire, then it's too hot. (low tire pressure)

*disclaimer* be sure to park your bus before checking the tires!

Jones'n4chrome wrote:...If you can't leave your hand on the tire, then it's too hot. (low tire pressure)

I agree that's a good "rule of thumb" (or hand...)

*disclaimer* be sure to park your bus before checking the tires!

I gotta agree to that, too, I ran over myself the other day, it sucked!

My son: "It was bad enough to roll my ATV in the ditch, but it really sucked to run myself over then lay there and watch it drive away without me."

Jones'n4chrome wrote:I run mine at 100psi. They ride good at that pressure and they don't get too hot.
If I drive for an hour on a hot day, then put my hand on the tread of each tire they are never too hot.
If you can't leave your hand on the tire, then it's too hot. (low tire pressure)

*disclaimer* be sure to park your bus before checking the tires!

Mark O also suggests 100psi. 120 is max psi. If you put in 120 cold, it will build up over 120. Also 120 psi would be a stiff ride.