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Discussion Starter · #1 ·
I just threw on some 35s without using a procal. My speedometer is off of course. If I never change it will that be a problem?

Just want to make sure no other system needs to know the accurate speed in order to function properly.

I don't really care if my speedometer is off. I rarely ever look at it anyways.
 

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Discussion Starter · #3 ·
I have a manual and I drive like a granny anyways. My mpg calculator says 19-20 with the 35 kevlars. So it's probably a bit higher.

If the calculator and speedometer is the only thing that's off then I'm not going to worry about it and spend the 150 on beer
 

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From an ethical perspective, your mileage will be under reported. In effect, your odometer will show lower than actual miles. I would get it calibrated, if for no other reason than that.

I have a manual and I drive like a granny anyways. My mpg calculator says 19-20 with the 35 kevlars. So it's probably a bit higher.

If the calculator and speedometer is the only thing that's off then I'm not going to worry about it and spend the 150 on beer
 

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From an ethical perspective, your mileage will be under reported. In effect, your odometer will show lower than actual miles. I would get it calibrated, if for no other reason than that.
Isn't it the other way around? Say 1 mile for instance. Your jeep will think you went a mile with 32s, when in reality you went a shorter distance with the 35s. So your milage will climb higher than actual road miles.
 

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It will absolutely mess with your ABS and ESP functions which can lead to a dangerous situation in an emergency avoidance maneuver. Might also give your insurance company an opportunity to not cover you if involved in an accident. 150.00 is "cheap" insurance.
 

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Isn't it the other way around? Say 1 mile for instance. Your jeep will think you went a mile with 32s, when in reality you went a shorter distance with the 35s. So your milage will climb higher than actual road miles.
Nope, larger tire circumference means it will cover more distance per rotation of the hub, therefore, you're going farther than the computer registered by running bigger tires than the computer is calibrated for. Part of what you said was right though. The computer registers a shorter mileage than actual road miles; road miles > actual miles without recalibration
 

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The dealer can calibrate it for you. I had mine calibrated after going with bigger tires and the dealer only charged me $60 which isn't bad and I don't have to worry about the speedo or odometer being off.
 

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My local dealer told me they can't flash the tire size on my 2015 JKU. I'm not sure if it's due to them not having the software updates yet like the issues flashpaq had or what. It is a small dealership in a small town so maybe they just don't have the computers or whatever. I'm wanting to get a flash cal so I can try out some efficiency tunes for my 6sp. Anyone know if they are ready yet?

Joe
 

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One of the few things that can actually void your warranty is tampering with the odometer. Knowingly adding larger tires to under report your mileage could be argued as tampering.
 
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