Help me out, if the 35 tires slow the speedo down, and then by upping the gear in the case a more aggressive ratio than stock, wouldnt that put the speedo back to stock or a little over actual?

 

My 35" KM2's measure 34.5 off the Jeep and 33.5 on with 28 psi. At 75, with 5.13's I'm turning 2600. Get the 5.13's; you won't regret it.

 

Yes it does adj for both tire and gear so the shift is adjusted accordingly.

 

Nope, changing gears in a JK has no effect on the speedo reading. The computer reads wheel sensors to determine how fast the Jeep is going.

Now if you had a TJ, changing gears will effect the speedo, because it uses a sensor in the trans to determine how fast the Jeep is going.

The Hypertech programmer fixes the JK speedo by changing the tire size in the computer settings, which also changes the shift points like mentioned earlier.

 

X2,
Im glad I didnt get the 4.88's.......the 5.13s are fine and sometimes I wish I had more gear

I have a 75 mile round trip to work, 50% is spent at 70mph and even though Im turning more RPM at that speed, my mpg actually went up compared to when I had the 4.10's with 35's. That combo couldnt even hold 70mph on flat ground without down shifting, let alone going up a slight hill or with a head wind factored in.

Now with 5.13's I can even hold 65mph on flat ground while pulling my ski boat, hills are still a down shift out of OD though

 

Chuck45 thanks your tire measurements are the kind of information I have been looking for. Until I started considering re-gearing I honestly did not realize a single tire size could have so much variance depending on manufacture.

 

I love RubyDoo's 35's Procomp Xterrains and 5.13:1 gears, seam to be a perfect match. When I did the reprogram of the speedo and odometer, the tires measured 34.25in on with 32 psi. Now everything seams to be perfect, Have yet to haul around the trailer but will due that next weekend and by then the breakin pieord will be done as well. She only loses about 1-3 mph on hills @ 65 with about a 5% grade with the cruse on.

 

So why do we have so much troble on the gear issue. Once you've done it it is so obvious that it is the right thing to have done. And lots of people have shared their experience regrearing. Why is it so difficult to get the point across?

My JK is a 4dr with a winch and lots of Rock Hard stuff (which is bullet-proof but heavy). I can't imagine what a 2dr with 3's and 5.13's feels like.

 

With what is in my signature and a full tank of gas with me in RubyDoo, she weights in at 5400 Lbs.