Ask an expert

I replaced two front tyres at Beaurepairs a month ago, the technician told me the tyre pressure being set at 34.
As AA recommends, I check the tyre pressure monthly. So I went to a BP petrol station and set the pressure at 34. When I pluged the air, the reading started from 38 to 34.
A few hours later, I bypassed a Shell petrol station, I set the pressure at 34, the reading started from 31 to 34.
Then I drove to another BP petrol station, set the pressure at 34 again, the reading started from 32 to 34.
I am wondering which one is more accurate?

As tyre pressure testing and inflation is offered free of charge, its hard to be critical of the gas stations equipment, but it is fair to say it would take a fair amount of punishment over time.

I would suggest you invest in your own tyre pressure gauge, then go back to the tyre store and ask them to reset all pressures. Your monthly check could then be done at your leisure and a visit to the gas station would be to inflate the tyres, if required, only.

A couple of psi difference is insignificant to be honest, the important thing is you are checking your pressures on a regular basis.