Tire Size VS Odometer Accuracy

[azwjowner]

For you guys not being a TJ site I got lots of help anyway

That's because although we purchased JLs, we all secretly wish Jeep still sold brand new TJs.

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[aeonixx1001]

Hey fellow Jeepers,
I bought a new (to me) Jeep, 2001 Wrangler Sport (TJ) 4.0L, It had 31x10.50 15 tires on it.
How do I calculate the actual mileage driven? I know different packages come with different stock tires.
I've heard you can change a small plastic gear in the trans. but is there a formula to do it?
Someone else said to flash the computer with the new info., I'm not sure my 2001 has that type of chip.
Thanks for any ideas

Go to Microsoft Copilot and put in the two variables and it will figure it out for you. Aint that AI a Bitch.

 

[aeonixx1001]

Go Youtube, they have a million videos on "how to select the correct tire size" for you. You want to keep the centerline as close as possible for a decent ride.

 

[Pismo61]

Hey fellow Jeepters,
I bought a new (to me) Jeep, 2001 Wrangler Sport (TJ) 4.0L, It had 31x10.50 15 tires on it.
How do I calculate the actual mileage driven? I know different packages come with different stock tires.
I've heard you can change a small plastic gear in the trans. but is there a formula to do it?
Someone else said to flash the computer with the new info., I'm not sure my 2001 has that type of chip.
Thanks for any ideas

quadratec.com/c/reference/jeep-speedometer-gear-tooth-chart

 

[Pismo61]

The speedo gear swap is easy 2 minute job to do in a TJ Sport.Did it many times myself.No computer programming needed.

 

[SoK66]

For your TJ you calibrate the speedometer via a small plastic gear that plugs into the transfer case. Do some googling and you can find a chart that shows a cross reference for axle ratio / tire size / speedometer drive gear. The gears are different colors based upon their tooth count. My former YJ had a speedometer cable, but TJs had a module and wiring to the Speedo. Those gears are fairly easy to change.

 

[Jeeps Luv Mud]

Thanks....All great ideas, I'll be working on checking them out

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