Tyre pressure set to 35 psi, a week later it was 58!!

vikramrkin

Hi,

I went to tesco petrol station two weeks ago and checked my tyre pressure and set all of them to 35 psi. After two weeks, went to the same tesco and checked again and it was showing at 58!! I got suspesious of the instrument there and went another tesco nearby and even that showed the same pressure of around 58.

I know these machines are not always fully accurate, but are they usually off by so much?

BTW, I have been using the same tesco from last 6 months and this had never happened. Also, both times, i checked pressure when tyres were cold.

Thanks
Vikram

Crabman

I would have put it down to machine inaccuracy but you say you visited a second machine which agreed with the reading from the first machine.

You haven't mentioned what sort of vehicle you have but I imagine tyres that should be inflated to 35psi would look visibly over-inflated at 58psi (assuming they could contain such pressure).

Are you sure you weren't reading the gauge upside down?

LincolnshireYokel

Nah, 58 psi is close to exploding, i dont believe it

forgotmyname

Or some kid used it to inflate his bike tyres to 55PSI and you only
glanced at it and assumed 35 PSI.

Very very doubtful it would be that far out.

Did you not think thats taking ages to inflate? My local station the pump seems
to go in spurts. 1 or 2 PSI then you hear it whirr a bit then it inflates again.

Not seen inside one but i presume they only have fairly small resevoirs. So the pump needs to run a fair bit. But its safer as its only storing a small amount of compressed air.

Sgt_Pepper_2

How did yet check them from cold?

You must have driven there.

marlot

Forecourt gauges get knocked about and can be wildly out. It might have been wrong when you first used it, and recalibrated between then and your second visit.

Buy a decent gauge and test the tyres cold. Something like this http://www.autoexpress.co.uk/products/products/272221/ring_rtg6_tyre_gauge.html

Or multi-test here http://www.autoexpress.co.uk/products/products/249793/tyre_pressure_gauges_tested.html

vikramrkin

Thanks to everyone for the reply.

You haven't mentioned what sort of vehicle you have but I imagine tyres that should be inflated to 35psi would look visibly over-inflated at 58psi (assuming they could contain such pressure).

Are you sure you weren't reading the gauge upside down?

I drive astra 1.8. The tyres didnt look much different with 58 psi in them or may be I didnt recognise them.

Definately not reading the gauge upside down.

Did you not think thats taking ages to inflate? My local station the pump seems
to go in spurts. 1 or 2 PSI then you hear it whirr a bit then it inflates again.

Yes, it did take long to inflate. I had to inflate them in two rounds as in put the 20p coin twice. But then I was checking them after two months and the readings were in the range of 15-17psi.

Nah, 58 psi is close to exploding, i dont believe it

Thats what I thought, not sure if if I have damaged my tyres now. Thats my biggest worry now.

How did yet check them from cold?

You must have driven there

I drove for 0.4 miles, not sure if that would make much difference to the reading.

As marlot suggested, I think it is worth investing in a gauge.

Is there anything I can do to ensure that I have not damaged my tyres by over inflating? I dont want them to explode on a motorway.

Thanks
Vik

Weird_Nev

If they haven't exploded then they'll be fine. Pressure like that could cause any weakness to fail, but so long as they're back to correct pressures now they'll be fine.

(Check the sidewall for max Psi rating of the tyre) 58Psi is high, but under double a "normal" inflation range.

floopnoodle

YOU'VE PUT 3.5 BAR IN, NOT 35PSI

3.5 bar is around 50psi, if you put just under 3.6 bar then you're up to 53psi. Allow 5% for tolerances on the one you used to read and the one you inflated with and you're at 58psi

Most digital machines have the option to display the pressure in in bar or psi, you just need to press the button to alternate between the two.

SteveJW

I'm surprised OP didn't notice a harsh ride, on my car increasing the rears by 10psi as recommended for fully laden high speed driving certainly gives a harsh ride

colino

I'm surprised you didn't shake your teeth out driving around with solid balloons like that for a fortnight. My car, even with its special, self pressure-reducing, rear alloys is very noticeabley uncomfortable if I put them to 35psi.