Tyre Pressures

[Graham Smith]

Have just been checking the tyre pressures on our car, and have noticed wildly different readings from the gauges I have available.



As you can see from the following photographs, the standalone dial gauge reads 40, the compressor dial reads 50 and the stick type (that I stole from my late father about 40 years ago) reads 49.

How accurate are these things, and if the answer is none of them, which is your preferred pressure gauge and how do you ‘know’ it’s accurate?

 

[TouringGodet]

That’s a good question.

For car tyres, one option is to calibrate your gauge by using an infrared temperature gauge. Drive your car a good bit to get the tyres up to operating temp, then measure the tread temp on the outside edge, in the center, and inside edge. Whatever tyre pressure yields consistent temps across the tread, plus or minus a few degress across the three measurements, note the pressure that each pressure gauge reads. That is your desired pressure for that gauge, for that tyre.

If the center temp is higher than the other two, the tyre has too much air. If lower, not enough air.

 

[Bill Thomas]

I had a pair of tyres fitted to my Car ,
A short while ago, Thought I had better check pressure and Nut tightness,
As an old mechanic, I could tell the pressures were much too high,
Just putting the gauge on, As it tried to blow the gauge OFF !,
They were 40 lbs instead of 30,

I also had it with my Step Daughter with a hire car, 60 lbs !!!!!, Instead of 30.

I trust the one on my foot pump, Within a few lbs.
Cheers Bill.

 

[davidd]

I use Intercomp gauges. They build good quality instruments and market mostly to racers. I use their durometer also.

Intercomp - Advanced Racing Technology | Intercomp Racing

www.intercompracing.com

David

 

[Michael Vane-Hunt]

Check your tyre pressure guage against a modern car with TPMs. I did this with several guages and my truck. Tossed out about half of the guages which were more than a couple PSI out.

 

[roy the mechanic]

Unless you wish to pay Snap-On money, go buy a cheap digital guage from your local parts store. Bill is right, when you have "the feel" the seat of the pants can tell.

 

[Bill Cannon]

At work I keep an old fashioned "pencil" slide gauge just for checking calibration of air line gauges.

 

[Normski]

I don’t understand how the sliding pencil type work but they are supposed to be the most accurate. I keep an inexpensive Draper one in my on bike tool kit.

 

[roy the mechanic]

The problem,for me, with the pencil guage is that most of them were given in a vehichle 's original tool kit. Most manufacturers were not famous for thier generosity in this area. If you use only one guage every time , at least the error will remain the same.

 

[mercurycrest]

I haven't used this, but read where it's supposed to be a good un'

Sealey Tyre Inflator with Gauge SA302 | at Zoro

Sealey - Tyre Inflator with Gauge available at Zoro.co.uk - UK's Leading Supplier of DIY Tools and Supplies'

www.zoro.co.uk