TYRE PRESSURE READING ON DASHBOARD

[3puddings]

How accurate do you think the tyre pressure readings are on the dashboard?

[italianjob1970]

How accurate do you think the tyre pressure readings are on the dashboard?

Not very! Mine varies, on all 4, by 2-3 PSI during a journey.
Should really try a long journey to see if they settle down.

[Philr]

The tyre pressures will change due the ambient temperature and during and after a journey.
I used to race and spent a lot of time analysing tyre performance as they are the only point of contact that allows steering and braking and hence staying alive or at least uninjured when it all goes t*ts up.
Pressures will vary depending on how the car is driven - gentle braking or hard, gentle cornering or late and sharp, how abrasive the road surface is, speed, age of tyre, compound, size and amount of tread.
So setting the pressures when the tyre is cold is the base line. The only variable then is the ambient temperature and this winter there will be some that will get warnings on the dash that one or more pressures are too low. Just pump 'em up.
Use a separate tyre pressure gauge not one that is part of your compressor or even worse a garage airline and just inflate to whatever Hyundai recommend.
Apart from checking the pressures manually every month also check the tread depth, look for cuts in the sidewalls, damage of any sort to a wheel as that can lead to leakage, nails in the tyre and so on - it may save your life.

[Deleted User 1130]

In general day to day non fully laden driving I've found that 38-40psi all round works for me. At 35psi my car does not ride as well and the steering does not feel as accurate. My tyres also look under inflated at 35psi.

[Pogleswood]

As I’ve got two slow punctures it’s useful to me every morning to check whether either one needs air.

[PhilHornby]

How accurate do you think the tyre pressure readings are on the dashboard?

It's hard to know, without a known accurate gauge to compare them with. I'd perform a comparison with another gauge and assuming you get the same results as the TPMS (or the same difference for each wheel), you'll have to something to compare against in the future. This comes in useful when the car is saying one thing, but your eyes are telling you something else (more common with the 'indirect systems', that just measure the no. of rotations in a known distance).

The tyre pressures will change due the ambient temperature and during and after a journey.

This is the first car I've had with 'direct' TPMS, that actually shows you the pressure readings (rather than just a fault light). Given that the TPMS sensors contain a temperature sensor as well as a pressure sensor, I expected it to apply compensation for the former - but it doesn't seem to.

I just acquired a spare TPMS sensor to do some experiments. It would be nice to have a contact-less method of interrogating the TPMS sensors, without having to drive the car.

[Philr]

Phil - I was an early adopter of an after market contact-less TPMS 15 years ago or more which allegedly gave tyre temperature and pressure. I was pretty certain that the temperature part was directly affected by the temperature of the wheel as the sensor and it's valve were metal. As the wheel got hotter mainly caused by braking the temperature went up. Checking the temperature with an infrared gauge showed the actual tyre tread to be anything up to 10 degrees below the sensor. It was really the temperature of the air in the tyre it was measuring directly affected by the temperature of the wheel.
Similarly the pressure was overstated, again probably caused by the heat of the air inside,but not by as much as we had a calibrated analogue gauge to check with.
As an aside when the TPMS was showing a tyre temperature of 80 degrees it was like driving on ice
I junked the system after about 18 months as the batteries in the sensors started to fail and were not replaceable. Hopefully this is one area that has been improved.

[alan sh]

Mine isn't that accurate. I have a decent gauge and set them all to 35. Inside, it can range from 33 to 38 when I set off. It then seem to settle down over the journey and goes from 34 to 37.

Personally, I only want it to tell me if a tyre is going down. My wife had a puncture in hers and it very kindly beeped and told her which tyre it was.

[DrElectron]

In my experience it's fairly accurate, inflating all the tyres to 35psi on my gauge shows 35 on the car, after a bit of driving they increase to about 37-38 which is expected with a slight increase in temperature, and return to 35 when cooled down again

[NLineS]

The tyre pressures will change due the ambient temperature and during and after a journey.
I used to race and spent a lot of time analysing tyre performance as they are the only point of contact that allows steering and braking and hence staying alive or at least uninjured when it all goes t*ts up.
Pressures will vary depending on how the car is driven - gentle braking or hard, gentle cornering or late and sharp, how abrasive the road surface is, speed, age of tyre, compound, size and amount of tread.
So setting the pressures when the tyre is cold is the base line. The only variable then is the ambient temperature and this winter there will be some that will get warnings on the dash that one or more pressures are too low. Just pump 'em up.
Use a separate tyre pressure gauge not one that is part of your compressor or even worse a garage airline and just inflate to whatever Hyundai recommend.
Apart from checking the pressures manually every month also check the tread depth, look for cuts in the sidewalls, damage of any sort to a wheel as that can lead to leakage, nails in the tyre and so on - it may save your life.

Fantastic advice there