This is a small Java Script utility that figures what speedometer driven gear will yield a similar speedometer reading after a driveline change.
I hope you find it useful.

Old Ring and Pinion
8.8 ratios - 3.08=40/13, 3.27=36/11, 3.31=43/13, 3.55=39/11, 3.73=41/11, 4.10=41/10
7.5 ratios - 3.08=37/12, 3.27=36/11, 3.45=38/11
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New Ring and Pinion
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Old Tire Size


New Tire Size


Current Driven Gear