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Old 06-14-2010, 10:06 PM   #49 (permalink)
texanidiot25
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Location: Cypress, TX
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Quote:
Originally Posted by sjr View Post
Im wondering about the "donut spare" the small spare tires that say Dont go over 45 on the side and they are good for 60 PSI , has anyone ever ran a set of 4 of these and seem how they handle and what kind of gas mileage improvment they provide? I have 5 or 6 15" donut spares I would like to try out but would like to hear some real life experiance with them Scott
If you want to have a death wish, sure. Donuts are only made to be temporary tires, and go bald in a very short amount of time. Their tread design is really only good in dry weather. They are skinny as hell, and provide very little traction. Also their outer diameter tends to be much smaller than that of your car's normal tires (to fit in the trunk) and would cost you more in fuel due to effectively changing the final drive ratio, than they'd save you in fuel due to a lower rolling resistance. And, I'm going out on a limb here, but I believe the higher pressure is to help support the weight of the car on such a tiny tire.

There is a reason why the manufacturer prints on there about speed limitations as well as mileage limitations.
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