I just recently changed to 5.13s and 37inch Wrangler MT/R W/Kevlar. I have a BullyDog GT Tuner that is set 5.13s gearing and 37.2 inch tires on the stock setting. I have noticed shifting lag on inclines and on the flat it seems to shift early. I find that often I have had to feather the throttle to get it to shift. Has anyone experienced this? It is starting to become annoying.

 

Dont the mtr's measure smaller than 37? Try dropping it to a 36.5

Stay muddy my friends

 

Similar set up but used AEV Procal. Entered my tires at 36.75. I note the same thing with the shift points particularly at interstate speeds.

 

Thanks for your input. I will try lower settings over the weekend and hopefully get better results.

 

I actually disconnected my battery when installing my snorkel I am running the Bully Dog Gt with 35" MT/Rs before disconnecting the battery it would hard shift after i disconnected it for several of hours i found that it shifted smooth again. Could be coincidence I dont know but worth a shot

 

Yes. I had to enter 35.5" to get my speedo to match my GPS speed. Yet I measure 36.25" with a square and tape measure???

 

I found data that claims the Good Year MT/R 37s are actually 36.8. The Bully Dog does not have a setting to 36.8 so I set it to 36.77 and it seems to shift better without the need to feather the throttle. Thanks for the input.

 

The 36.8 is the unloaded height when mounted on a nominal wheel width. You should use the measured diameter once on the Jeep for the best shifting and most accurate speedo

 

Measure from the ground up to the center of the wheel. Multiply by two and that's gonna get you very close. Can't beat using a GPS to dial it in though.

 

I got the same thing. Unfortunately the Flashcal and my 14 don't work together.