Tyres

My tyres are over inflated. Tyre garage put in 37 when should be 36. I have tried 3 times to correct my tyre pressure using supermarket compressor. I set the pressure, put the nozzle onto the valve. When the ma beeps I presume the pressure has been done, as I drive, it shows my tyre pressure is still 37. One of my tyres that showed 34 after my last attempt is also 37. Do I need to let air out of all my tyres, to then just let them be inflated, or could there be a fault with the machine, as it should be 36 as I set it.

I presume your car has a readout of individual tyre pressures? Have you tried resetting the monitoring?

Remember as you drive your tyres heat up and pressure increases- stated tyre pressure is for cold tyres.

Personally I use a foot pump and a hand held pressure meter, you can get a digital one from halfords for about £5. What to do is pump up slightly higher than what you want and use the hand held meter to let pressure out (hold it against the valve slightly askew) until I get the pressure I want.

1PSI is IMO not worth worrying about... it's within the margin of error for car tyre inflation machines.
OTOH if you had a tyre inflated to 45 when it should be 35 that'd be a problem

if it's disturbing your peace of mind you could deflate your tyres before trying to inflate them back to the correct pressure with the supermarket machine - or try and find a garage with an old school manual tyre inflater, there are still some of these around, the one near me is an edge of town independent filling station with an MOT test station built on the back, they let you use the inflater for free if you buy some fuel - that's probably the type of place that would still have them.

Thank you for your reply. I will just buy an air compressor.

Ok - the ones that run off your car battery are a bit rubbishy though, might be useful if you have a constant slow leak through a porous wheel but Supermarket inflaters are going to be more accurate and +/- 1 PSI isn't worth worrying about.

Ok - the ones that run off your car battery are a bit rubbishy though, might be useful if you have a constant slow leak through a porous wheel but Supermarket inflaters are going to be more accurate and +/- 1 PSI isn't worth worrying about.

As long as it wasn't free in a Christmas cracker, the compressors that you plug into your car work perfectly fine and you don't need to drive to the supermarket to use it.

Put it this way... I've not had a good experience of them.