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I would like to start to fine-tune my tire pressures to handle bumpy roads above all else, but before wasting too much time, it would be nice not to have to drive 100M before seeing the pressure settings.

In addition, I've been finding that the TPMS readings from my car frequently disagree with needle style pressure gauges, as well as the gauge on my electric tire inflator.

Is the TPMS reliable in absolute terms, or just relative?

Does anybody know of a tool that is both precise, and accurate for tire pressure?
 

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I would like to start to fine-tune my tire pressures to handle bumpy roads above all else, but before wasting too much time, it would be nice not to have to drive 100M before seeing the pressure settings.

In addition, I've been finding that the TPMS readings from my car frequently disagree with needle style pressure gauges, as well as the gauge on my electric tire inflator.

Is the TPMS reliable in absolute terms, or just relative?

Does anybody know of a tool that is both precise, and accurate for tire pressure?
TPMS sensors aren't very accurate an should not be relied upon for accuracy. Try are designed primarily to detect drastic drops in tire pressure so accuracy isn't needed for that.


Stick to a digital tire pressure gauge that will give you the pressure to 1/10th accuracy. They cost about $10-$20. Available at any auto supply store.
 

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It is relatively close. It requires wheel rotation to be read. Shoot for 33/35 at ~70 or whatever your typical daily base ambient temp is. Rear tires get greasey real quick above 40 degrees hot even on the street. This is why it handled so poorly for Randy Pobst last year. I'd be glad to elaborate it more with you as I have had my at the track and have had an Elise since 2005. Some here with a bit less experience than I disagree.
 

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NO! doesn't work that way. If you have the Corsa tires they will probably be OK to ~40 hot but the regular PZeros start to get greasey above ~38. Placard is still the goal until you know your car but Lotus has a history of being a bit excessive with cold pressures to a point where there are wear issues and traction issues with aggressive driving once they're hot. Much of that would diminish with the use of Nitrogen but that is a bit of a pain.
 

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Much of that would diminish with the use of Nitrogen but that is a bit of a pain.
How does that work?
I thought that all gases were following the law something like PV=T ?
So Oxygen, CO2 or Nitrogen are all the same.

If the water is not a present in the tire as a liquid then its pressure is constant. So the vapor pressure of the water is fixed, unless you cool it down and then some of the water falls out. but when you heat it the amount of water is fixed so the vapor pressure of the water is fixed or follow the pv=t law???
 

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I defer to a track engineer on this but, for example, whereas I will typically get a 7-8 degree temp rise during a session if i started cold, my friend with identical tires but nitrogen filled gets ~half that temp rise thus giving him MORE consistency from start to finish of a session. Same applies to street use. However on street an "air" filled tire may rise 4-5 lbs whilst the nitrogen filled tire may change 2-3 lbs.
Experts help me here as I am just getting a handle on this after hearing all the hype for a few years now. It is following the "LAS" but the different molecules are affected, well, differently.

Instead of having air filled tires that take 3 laps to "wake up" feel good for 1ominutes then end the session too high on pressure, nitrogen stays in the sweet spot of performance more readiy.
May try this myself next year. esp if I can buy a cylinder to play with!
 

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:confused:What he said
 
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