Tyre Pressures

[dazwan]

I've been doing lots of Motorway driving recently and have noticed that my tyre pressures appear to drop a lot quicker than when I am just driving around town (I seem to be losing about 1-2 psi a week on all tyres).

Bearing in mind I am doing long trips of 4+ hours at a time, I was wondering if it was being caused by the tyre's heating up. Is it normal to expect to have to inflate my tyres more often when doing lots of long stints at motorway driving?

[GT4 BOOSTER]

heat in the tyres increases the pressure inside , thats why they recommend a certain pressure and not to go over it , cos if you put 32 in , by the time the tyre heats up it maybe goes to 36 eg only ,i would think just the trips you do and the cars weight will push the pressure out of the tyre over time.

[System~G]

I spend a lot of time driving up and down motorways now and I only seem to need to top-up air once every two months. But then again I need to put about 4 or 5psi in.

How long have the tyres been on the car? They may just need refitting/sealing or valves tightening...