Tire pressure dash reading.

[Ozstung]

Strange, mine's been spot-on. Overnight cold, I inflate to 36, flip the display for tire pressures, drive past 35MPH and each tire pressure pops up at 36. However, what I have noticed is more down to physics: the tire pressures start to increase very unevenly until they all ready operating temperatures around 38-40psi. What I mean by physics is a few things: the weight distribution is not perfectly centered between the tires, so even though the car is 52/48 front to back, the left to right may be different; if your drive has more right turns than left, your driver's side tires will start heating up first, etc. However, I've never seen a car where the tires heat up at such rapidly different paces until they all reach operational temperature. The vehicle seems to inherently have a little more weight on the passenger side than the driver's side (which makes sense when you add a driver) from what I can surmise observing my tire pressures as they heat up.

Yes mine reads exactly what the air pressure pump at the service station is set to. And like you say the front passenger side reads differently when up to temperature Its always one pound pressure difference to the driver side. And its always one pound less. Its probably because the front drivers side has a 90kg body sitting next to it. The back tyres always remain consistent.

 

[MerlintheMad]

Now, that’s a big discrepancy. If you are paying for TPMS service, this shouldn’t happen if they are adjusting them during the “service”. Which brings back my question, what are we paying for if the system can be that much off. Merlin, you just had your tires installed, I would ask them to fix that or explain why the difference since the change.

This afternoon I had Big O raise my psi to 40 front and 38 rear. They put in c. two pounds, after I had driven c. 12 miles to get there. So, my tires were maybe c. two pounds low (I figure c. two pounds will build up from driving). When I had arrived, my FL tire showed 36 psi on the LCD. But the tire gauge at the wheel showed 40 psi. In the time it took to get the mechanic to put air in my tires they must have lost most of the extra pressure from driving. Anyway, an interesting thing occurred: after the psi was raised to 40 front and 38 rear, the LCD changed to show only a one pound discrepancy: 39 front and 37 rear. Will this stick? Or will the TPMS revert back to being four to five pounds lower than at the wheel? I guess tomorrow will reveal the answer.