tire sizing question, math maticians.....how will it affects gear ratio?
04-07-02, 03:11 AM
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tire sizing question, math maticians.....how will it affects gear ratio?
Ok, stock tire size on my SE is 185/70/14, according to Tire Rack. If I bought 2 tires for the rear, in size 205/55/14, how much would that effect my gear ratio?
04-07-02, 03:15 AM
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This is a tough question, because the height of the tires, although supposedly determined by the width divided by the aspect ratio, is not the same brand by brand.
04-07-02, 03:25 AM
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I will do some simple math, and probably make myself look like a moron.......
185 / 70 = 2.64285
ok......now......
205 / 55 = 3.72727
so, this will definately have an effect on my final gear ratio. i know the car has 4.10's. but, tire height also plays a part in all this.
185 / 70 = 2.64285
ok......now......
205 / 55 = 3.72727
so, this will definately have an effect on my final gear ratio. i know the car has 4.10's. but, tire height also plays a part in all this.
04-07-02, 04:08 AM
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04-07-02, 04:16 AM
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oh sweet, that link is very cool. But, I still am lookin for someone to come up with a gear ratio for me..........something that would be higher than 4.10 cause of the shorter tire? or would it be lower than 4.10?
04-07-02, 04:13 PM
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UniqueTII is correct, the maths isn't reliable because tire manufacturers obviously don't know how to use a ruler! 
But we can use it as a guide.
A 185/70x14 tire should be 615mm in diameter, a 205/55x14 should be 581mm, which is ~5.5% smaller. This would be the same as changing to a 4.34:1 diff. You should always aim for the original overall diameter; the closest profile for that width is 205/65x14 (Ø622mm).
But we can use it as a guide.A 185/70x14 tire should be 615mm in diameter, a 205/55x14 should be 581mm, which is ~5.5% smaller. This would be the same as changing to a 4.34:1 diff. You should always aim for the original overall diameter; the closest profile for that width is 205/65x14 (Ø622mm).
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