Tyre pressure sensors

[Grumps.]

Are the built into the wheel type reliable?

I’ve just checked a new car on the manufactures app and the pressures are way over the recommend, and yet using a hand held device, this reads considerably lower although not down near where they are supposed to be!

[Rough101]

I have one that reads 1psi less than the others despite all reading the same on a hand held guage.

Remember of courses that they only read when they are spinning and the car driving.

I can watch mine rise 3-4 psi during a journey, then settle back cold.

[Pica-Pica]

Do you mean reliable?, or do you mean accurate?
I have TPMS (proper in wheel pressure sensors) in my ‘66 plate BMW 335d wheels, which of course are staggered, and also JJ rims (for run-flats).
Using a Halfords digital gauge and a TireTek analogue gauge (which match each other’s readings), I find that, when set at a desired pressure with these gauges when cold, the TPMS reading is down by 2 to 3 psi when starting off and only matches the gauge cold-set pressure after 20 miles or so.

I assume that having a read out that matches the tyre label value AFTER the tyre has warmed up meets the customer expectations of non-technical users.

As a further note, I have established what is a good pressure for me, with the run-flats and with the local roads in mind. That value is somewhere toward the fully-laden pressure values. I also can comment, the runflat rims and tyres lose very little pressure, so I only adjust them when winter sets in.

In 6+ years and 50k miles, I have never had any issues with my TPMS. It did show a pressure drop of 3psi in one tyre (triggering an amber signal), and after lengthy checking, I found a screw in the tyre. I replaced the tyre, as it was half-worn, I got a good deal, so after saving tyre seal cost, I was only about £60 down.

So, yes, I find mine reliable and accurate.

Edited by Pica-Pica on Thursday 29th June 13:16

[Grumps.]

Thanks guys.

Yes, sorry it was more a case of them being accurate than reliable so with that in mind they are certainly way over pressurised!

Basically they are all sat around 60psi on the Tpms but my gauge, albeit cheap and nasty hand held from Amazon reads about 5psi lower, and according to the owners manual, they should all be around the 50psi.

I guess I need to get a better handheld gauge so does anyone have any other recommendation?

I don’t have a Halfords near so will probably have to be an online purchase

Edited by Grumps. on Thursday 29th June 13:43

[Pica-Pica]

I have found pencil gauges hard to read.
I have used this:
https://www.halfords.com/tools/garage-equipment/br...
Then bought this, I thought it would be more accurate, but it reads the same value as a Halfords one and is more awkward to use.

https://www.amazon.co.uk/TireTek-Premium-Tyre-Pres...

Using one of these, I would start with a cold setting as stated on the cars tyre pressure sticker, then adjust up or down to suit your requirements (comfort, steering feel, handling), then see what that gives you as a reading on the TPMS, just after you drive off and when you have done 20+ miles.

[Grumps.]

Brilliant cheers.

I actually found my old Draper tyre inflator and plugged that in and it was giving readings close to the tpms so I used the gauge on that to reduce the pressures to just above label suggestions.

I’ll reset the tpms when I go out later to fill up.

[MustangGT]

Grumps. said:

Thanks guys.

Yes, sorry it was more a case of them being accurate than reliable so with that in mind they are certainly way over pressurised!

Basically they are all sat around 60psi on the Tpms but my gauge, albeit cheap and nasty hand held from Amazon reads about 5psi lower, and according to the owners manual, they should all be around the 50psi.

I guess I need to get a better handheld gauge so does anyone have any other recommendation?

I don’t have a Halfords near so will probably have to be an online purchase

Edited by Grumps. on Thursday 29th June 13:43

Just as a matter of interest, what car needs 50 psi in the tyres? The most I have come across was about 38 psi I think.