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ok i picked up a set of stock 18" to replace my 16" stock tires. now my speedometer is off by about 5 miles per hour. what do i need to do the correct this, and keeping the tires is part of the solution.
 

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Rim size doesnt matter, tire size does, specificallly the height. Need a pprogrammer like procal or others havenentioned a much cheapet app and obd they say works well. Just have to get one and figure out rhe new size, because stated heaight (33, 35, etc) wont teanslate to actual height. But it will give you a starting point.

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Discussion Starter #3
Rim size doesnt matter, tire size does, specificallly the height. Need a pprogrammer like procal or others havenentioned a much cheapet app and obd they say works well. Just have to get one and figure out rhe new size, because stated heaight (33, 35, etc) wont teanslate to actual height. But it will give you a starting point.

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thanks yes i know the rim size really doesnt matter but the tires are close to 2 inches from old to new.
 

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thanks yes i know the rim size really doesnt matter but the tires are close to 2 inches from old to new.
So thats a starting point, need a procal or maybe someone will chime in with an effective obd and app programmer. Cant just swap out speedi gears like you could with the TJ's

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Procal is the main go to for most people. I have Aeroforce gauges, so used that. I used the new tyre dimensions as a starting point, then checked against GPS on long straight stretches of road. I was still off by a few percent.


So then I adjusted the stored figure by that percentage and it is spot on throughout the range. (After correcting, because I went the wrong way first, of course! :p )
 
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