TPMS.... accuracy

Mike and his Macan · Post by **Mike and his Macan** » Mon Aug 20, 2018 1:54 pm

Has this been covered before? So I pumped up my tyres today and found 1 psi difference from reading TPMS to tyre compressor at shell station ... just also to say I run my cars 1 psi above normal recommendations, it now handles like a different car , just goes to show !

happy days · Post by **happy days** » Mon Aug 20, 2018 1:59 pm

I wouldn't think either would be notoriously reliable instruments!

SAC1 · Post by **SAC1** » Mon Aug 20, 2018 4:20 pm

Best to check the tyre pressures when they're 'cold', before driving and with an accurate gauge.

For example:

Nuclear Nick · Post by **Nuclear Nick** » Mon Aug 20, 2018 4:41 pm

Mike and his Macan wrote: ↑Mon Aug 20, 2018 1:54 pm Has this been covered before? So I pumped up my tyres today and found 1 psi difference from reading TPMS to tyre compressor at shell station ... just also to say I run my cars 1 psi above normal recommendations, it now handles like a different car , just goes to show !

How much did you have to put in? Did the MFD say it was necessary?

Why do you run yours 1 psi over the recommended pressure?

Paul · Post by **Paul** » Mon Aug 20, 2018 5:15 pm

Regarding the accuracy, I use a hand held Michelin digital guage (again from Amazon!) and set to 2.3 / 2.5 .
The TPS gives exactly this when setting off and then rises by a couple of tenths as I would expect as the tyres warm up.

Edit - this guage....

https://gb.michelin-lifestyle.com/en/mi ... sure-gauge

Mike and his Macan · Post by **Mike and his Macan** » Mon Aug 20, 2018 5:59 pm

I was hoping someone would recommend a tyre gauge... I run fronts at 34 psi... rears at 37 psi... 1 psi over, the reason being is one that I live in Milton Keynes as I’m sure you are aware of the Amount RBs, the second reason is that the recommended tyre pressure is a minimum setting.. so mine are recommended 21 inch ... at 33 psi , however this pressure obviously increases with heat/ speed , as a result my tyres are not reaching temperature ( higher psi) due to my short journeys , so the 1 psi increase I put in makes up for the heat I don’t generate. Iv been doing this for the past 7 years due to a chance meeting with a tyre technician/ part time experience day driver. Also as a result my outer edges of my p zeros have always remained in fantastic condition and my tyre wear has always been even across the whole tyre..... it works

Deleted User 1874 · Post by **Deleted User 1874** » Tue Aug 21, 2018 11:38 am

Mike and his Macan wrote: ↑Mon Aug 20, 2018 5:59 pm I was hoping someone would recommend a tyre gauge... I run fronts at 34 psi... rears at 37 psi... 1 psi over, the reason being is one that I live in Milton Keynes as I’m sure you are aware of the Amount RBs, the second reason is that the recommended tyre pressure is a minimum setting.. so mine are recommended 21 inch ... at 33 psi , however this pressure obviously increases with heat/ speed , as a result my tyres are not reaching temperature ( higher psi) due to my short journeys , so the 1 psi increase I put in makes up for the heat I don’t generate. Iv been doing this for the past 7 years due to a chance meeting with a tyre technician/ part time experience day driver. Also as a result my outer edges of my p zeros have always remained in fantastic condition and my tyre wear has always been even across the whole tyre..... it works

That makes sense in theory, but 1 psi is pretty insignificant, especially if you are relying on TPMS or tyre compressor gauges! Even in F1 we wouldn't worry much about that kind of delta, even down at 17 psi where 1 psi is much more critical! Nothing wrong with your target pressures, but 33/34 psi would feel and wear the same. You would have to make a much bigger pressure change to significantly influence tyre wear and handling.

But if you want perfection you do need an accurate tyre gauge and if you seriously want to control your pressures to 1 psi accuracy you'll also need to keep adjusting them with changes in ambient temperature/pressure as otherwise they will vary quite a bit - especially in our f***** up climate that can go from 10-30 degC from one day to the next!

Mike and his Macan · Post by **Mike and his Macan** » Tue Aug 21, 2018 12:26 pm

totally agree without the climate! I have to say I really can feel the difference in psi change, I am a bit ocd though!

bennachie · Post by **bennachie** » Tue Aug 21, 2018 7:48 pm

Bet you can't....................

Nuclear Nick · Post by **Nuclear Nick** » Wed Aug 22, 2018 7:03 am

No, you won't feel 1 psi difference, and it won't make any difference to handling or tyre wear, hence my question about the reason for doing it. But if it helps psychologically there's no harm in it.

TPMS.... accuracy

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