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Old 12-08-2008, 02:02 PM   #4 (permalink)
cfg83
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Join Date: Dec 2007
Location: Southern California
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1999 Saturn SW2 - '99 Saturn SW2 Wagon
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90 day: 40.49 mpg (US)
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Piwoslaw -

Quote:
Originally Posted by Piwoslaw View Post
I'm looking for winter tires and would like narrower wheel hubs for them. So I find this page called "The Wheel and Tyre Bible", which has lots of cool info. Here's the location:
Car Bibles : The Wheel and Tyre Bible Page 1 of 2
On page 2 there is a section on tire inflation, starting from "Checking your tyres" about 2/3 down the page. Among many things, the author comes to the conclusion that door sticker tire pressures are on the low side and a better rule is max pressure -10%. This gives just under 40psi if the max is 44psi. The whole page is really nice to read.

Our car has a door sticker of about 36psi, but the max on the tire is 51psi. Going with the max-10% rule, I should pump up to about 45-46psi. BUT the tire also has a big warning, which states (in slightly different wording):
Terrible things will happen if:
1) You underinflate your tires,
2) You inflate them over 40psi.
I keep them at 40, but am wondering if I can go up to 45psi?
That's one of my favorite sites for tyre stuff. I have the URL in my garage.

From my POV, the "10% rule" is a great starting point for increasing tire pressure. I know I can recommend that to someone with tires in good condition. The person is increasing pressure for road handling *performance*, not MPG. The site also states that the rule a starting point. You have to find the sweet spot for your car/tire combination. Since our goals on Ecomodder are different from the URL, you could start with the 10% rule and bump up as needed.

CarloSW2
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