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Old 04-18-2011, 03:24 PM   #1 (permalink)
Kodak
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Tire pressure and diameter

So I was searching through some EM stuff and found something that said that increasing tire pressure would increase the radius of the tire, thus requiring speedometer recalibration. It made sense that - even to a micro degree - the tire would be slightly larger.

I'm considering upping my pressure a bit. It's currently at door-frame spec (33psi), but the tires are rated for 44. I plan on starting with a jump of 2psi and gauging how much harsher the ride feels.

Will a speedometer recalibration be necessary, and is it easy to do?

If my understanding is correct, the speedo itself will read slower than I am actually traveling - correct?


Here's what I was talking about:
http://ecomodder.com/wiki/index.php/...o_max_sidewall

[/URL]/Increase_tire_pressure_to_max_sidewall
Quote:
Note: When testing MPG improvement the increased pressure will increase the tire radius therefore a scangauge or similar device will not display accurate efficiency until its recalibrated. A standard back to back test using the scangauge MPG output will not give reliable results
The ideal method of testing involves checking the amount of fuel used when traveling at constant speed between 2 defined locations for different tire pressures.


Last edited by Kodak; 04-18-2011 at 04:48 PM.. Reason: Forgot to link...
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