16 Unlimited Ways

Guys i have red numerous threads on upgrading tires and then using AEV procal...
Can't seem to understand everything going on...Having said that can you tell me please...
I have a 2012 Wrangler Sahara "Arctic" - Automatic - 3.21 gears - Smittybilt XRC front & rear bumpers-
Procomp LT315/70R17 Xtreme Tires...Rubicon Express 2" Lift...Now i measured my tires installed on rims they come
out at 34"...I programmed the AEV Procal it seems to be always wanting to downshift alot ...I have
plenty of power is this normal or should i reprogram for measurement of tire 34.7...Just wondering is this
going to affect my transmission in the long haul here...

renegade4x4

It seems to be wanting to downshift a lot because of the gearing. .75" on the procal isn't going to make a big difference but you did measure the correct way. My tires are 33s and I regeared to 3.73s. IMO 4.10s would be a good choice for you.

ronjenx

An easy and accurate way to measure tire diameter:
Stick a piece of chalk in the tread.
Move the Jeep until there are two chalk marks on the pavement.
Measure between the chalk marks.
Divide the measurement by 3.1416.
That's your tire diameter.
It removes the variables encountered with other methods.

RedJK2

You can also use a GPS to check your speed and adjust the ProCal accordingly.

16 Unlimited Ways

I know the extra weight does not help...Thought 3.21 gears would be o-k...

Anglico1

3.21 gears with that size tire is just not going to cut it. I would regear. I personally am running Goodyear Duras 315/70R16 with 6 speed and have regeared to 4:88. My friend is more in your boat with a 2012 and 35's he has 3:73 gears. He was also having the shifting issue then got the Pro Cal.

I would go with at least 3:73 or maybe 4:10

Good luck