Quote:
Originally Posted by DBASRA
I just replaced my factory tires on a 2005 Civic Hybrid and I dropped about 8 miles per gallon overnight. I am going to take the tires back to Sam's Club but I need to find some more effecient tires....does anyone have any suggestions?
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First, you should be aware that new tires will consume more fuel than worn tires - everything else being equal. This is due to more mass in the tread - and more mass generally means higher rolling resistance - all other things being equal.
Secondly, the pressure written on the sidewall of a tire has nothing to do with RR or fuel economy - except that running higher pressure helps fuel economy, but that would be true regardless of what is written on the sidewall.
The regulations which govern what can be imprinted on the sidewall are pretty vague - they only say "maximum", and different tire manufacturers interpret the regulation differently. The "max" pressure is based on a "tire standard" and that is also vague. Put another way, there are no tests that govern what CAN be imprinted, nor are there are standards that govern what SHOULD be imprinted, but the standard says that for passenger car standard load tires, the choices are 35, 44 or 51 psi - all very reasonable values for any given tire construction. DO NOT use sidewall pressure as a guide for anything other than what it says - Maximum.
Lastly, you should be aware that a tire's rolling resistance is also controlled by the tread rubber compound. Traction, wear, and rolling resistance are all part of the equation - and in order to get good RR, treadwear and/or traction have to be sacrificed. So if you see a tire with a 600 treadwear rating, you can guarrantee it will not have good fuel economy.