Tire size, gear ratio

[Bob502000]

I have a JT Rubicon that has a lift and 36 tires on it. Forget the gear ratio setting.

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[Jeep Rookie]

What tire comes in 36?
Closest would be a KM3 at 36.5 but is referred to as a 37.
Just curious as I have searched pretty hard.
Thanks

 

[Gren71]

Ive actually been curious about this myself. I used my flashcal to set it to 4.10 and it feels sluggish...I assumed it was the new tires. Ill reset it to “factory” tomorrow and see if there’s any difference

 

[sodak]

With 37" tires it won't shift to 8th gear...can't get mine to do it..if you want 8th back..you will have to Physically change the gears in the axles to a lower number..like 4:88 or 5:13.Make sence

 

[Jeep Rookie]

With 37" tires it won't shift to 8th gear...can't get mine to do it..if you want 8th back..you will have to Physically change the gears in the axles to a lower number..like 4:88 or 5:13.Make sence

 

[Otter155]

I hope this comes across in the nicest way possible; but I want to mention that you should only be changing the options in the tuner to reflect what is actually on the vehicle. Changing gear ratio up or down will not be good for the vehicle, and I imagine would perform subpar. If you have 4.10 gears please keep the tuner at that gearing. If the gears were redone, and you physically have 4.56 or 4.88 gears, then the tuner allows the user to adjust the computer to match the physical gears.

The reason we use the tuner for the tires is so the computer knows that every revolution the tire goes x distance. This will affect the speedometer and the odometer. Also changing the gears with the tuner to reflect incorrect gears physically in the differentials, would mean that shift points are potentially off. I'm not sure how this works with the new 8-speed auto.

 

[Bob502000]

What tire comes in 36?
Closest would be a KM3 at 36.5 but is referred to as a 37.
Just curious as I have searched pretty hard.
Thanks

Nitto's say 37 on them but when you measure the left front, they are actually less than 36.

 

[ShadowsPapa]

If you change tire size settings - it should be smart enough to know.. why would you need to change any other setting - especially gear ratio?
When racing and determining your potential times, you change tire size in the calculator there's nothing else to change because you have not changed anything else. The system should know - hey, at xx RPM and XX transmission gear (as long as the transmission gear ratios are programmed in correctly), anyway, at the given RPM and gear ratios, and tire size it knows the tires will either turn fewer or more revolutions per mile (or per xx yards) so - why would you change anything else?
If it can't get the tire size understood - it's not very smart.
If I know all the numbers I can tell how many engine revolutions will be needed per mile - if you give me a different tire size - I can adjust - why wouldn't that device?

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