rearviewmirror -
Quote:
Originally Posted by rearviewmirror
Tire Size question:
The Saturn calls for a 185/65-15, my car has 195/60-15 on it currently. Could this wider although stiffer tire cause the fuel economy to drop by 1-2 MPG? I'm just curious, if this is the case I might consider switching to some thinner LRR tires sooner than later.. Of course being hasty would incur a cost that would take a long time to recoup in saving a few MPG's.
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You can see the effect here :
http://www.miata.net/garage/tirecalc.html
Attachment 634
From what I can tell, when your tires were new, they were probably making it appear like you were getting more MPG than you were. Why? Because the odometer would be recording more miles over time than with the stock tires.
But the above is not proof because the odometer can be off too.
Assuming you are using your odometer to figure out your MPG, you should use a GPS to get the real scoop on your MPG :
New shoes (aka tires)
http://www.gassavers.org/showthread....ighlight=shoes
Based on my calculations, I am getting a 2% bonus over my odometer. That doesn't come out to 1-2 MPG, though. It is more in the range of 1/2 to 3/4 MPG.
NOTE : You're right about the cost. Since I drive freeways that have rain grooves (imagine the road lining up with the tread on my tire), I really feel the car "wiggle" at freeway speeds. Sometimes I feel like a phonograph needle. If only my tires had good songs on them
!!! Because of that, I have not taken advantage of my 51 PSI rated tires. I will probably test them at 50 PSI for fun one day, but not for a living. Except for that,
, they're very good tires.
CarloSW2