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is it possible to adjust the speedometer for bigger tires?

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mudman1

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Discussion starter · #1 · (Edited)
i read when you put on bigger tires, the speedometer will be inaccurate.

is it possible to have the speedometer adjusted? if so, could myself or the average mechanic do this? and how much would it cost? the jeep is a 2007 wrangler.

also, when the speedometer is inaccurate, does it create inaccurate mileage for the car too? or is just the speedometer incorrect? if the odometer would be incorrect too, is there a way to adjust both the speedometer and odometer?

thanks
 
#3 ·
Your JK does not use the gear, it's electronic and needs to be re-programmed.

There are several brands that provide different levels of functionality and priced accordingly.

I used the Pro Comp Accu Pro that only corrects tire size and gear ratio, and was less than $200. Other types are made by SuperChips and AEV.

Yes, your odometer will be off until it is re-programmed.
 
#4 ·
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#5 ·
What year did they stop using the gear and switch to eletronic? I have a 2006 TJ with six speed transmission.
 
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#6 ·
mudman1 said:
i read when you put on bigger tires, the speedometer will be inaccurate.

is it possible to have the speedometer adjusted? if so, could myself or the average mechanic do this? and how much would it cost? the jeep is a 2007 wrangler.

also, when the speedometer is inaccurate, does it create inaccurate mileage for the car too? or is just the speedometer incorrect? if the odometer would be incorrect too, is there a way to adjust both the speedometer and odometer?

thanks
Click to expand...
It depends on the size of the wheels as well. If they are 32 inches or smaller, the dealer can do it for like 50 bucks, but if they're over 32's, it'd probably be better just to order something to do it yourself.
 
#7 ·
nellanaesp said:
It depends on the size of the wheels as well. If they are 32 inches or smaller, the dealer can do it for like 50 bucks, but if they're over 32's, it'd probably be better just to order something to do it yourself.
Click to expand...
Why would that matter? It's a computer. If they can adjust for 32's they should be able to do 33's, 35's, even 40's.
 
#8 ·
Scooter_Trash said:
Why would that matter? It's a computer. If they can adjust for 32's they should be able to do 33's, 35's, even 40's.
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From what I understand the dealer's equipment (whether software or hardware) limits them at 32" because that is the largest tire that comes on the Wranglers from the factory.
 
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#11 ·
AEV procal worked for my regear and 39" tires. also recalibrated the steering for dead center so the ESP didnt go crazy. i recommend it since it was easy to do, quick, and 0 issues with my build.

5.5" RK coil over, 5.13 gears, 39" tires. on stock v6 and 6 speed.
 
#12 ·
The odometer will be off as well as the speedometer when you add larger tires. As mentioned above you will need an aftermarket programer in order to change the tire size in the computer with anything larger than a 32. I went the AEV Procal route, only 129 and worked very well. R&P is ring and pinion which refers to your gear ratio. Depending on the model/options you have it will be 4.10, 3.73 or 3.21 I believe.
 
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