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bigger tires... difference in mph

Old Dec 4, 2011 | 06:24 AM
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Default bigger tires... difference in mph

hey CF,
I just put on my 31's and it was a large upgrade from the pizza cutters i was running (26's maybe) my question: whats the difference in MPh on the speedometer. Im thinking 5-6 mph, and does it get wider the faster i go? Id like to have a general idea since the popo here are A-holes. thanks

~Stout
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Old Dec 4, 2011 | 06:53 AM
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http://www.grimmjeeper.com/gears.html
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Old Dec 4, 2011 | 07:36 AM
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abt that....
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Old Dec 4, 2011 | 07:56 AM
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yes, you're speed is off by a percentage. meaning if it is off my 4mph at 20 is would be off by 16mph at 80
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Old Dec 4, 2011 | 07:58 AM
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you can measure the percentage difference between factory tires and your new tires,

then use that to tell the percentage difference between you speedo speed and actual speed.

i would put the equation for it, but its way to early and my head is pounding.



or, you could just use a GPS, or get the right speedometer gear.


i think the math is
(old tire height) divided by (new tire height) = A

A is your percentage

then (speedo speed) + A%

like this
28 (old) divided by 35 (new) =20% (or .20)

65mph(speedo speed) + 20% = 78mph

but to do this you need the actual tire heights (use a tape measure)

Last edited by N20jeep; Dec 4, 2011 at 08:03 AM.
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Old Dec 4, 2011 | 08:26 AM
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thankyou, that makes sense to me.
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