Reading posts on this site, I've come to understand that I'd get better off the line acceleration if I switched from 4.10 to either 5.13 or 5.38 gears on an automatic Rubicon saddled with 35'' tires. It's a daily driver at near sea level with sporadic offroad treks. Gas mileage is a non-issue.
Which would suit it best : 5.13 or 5.38 gears ? Thanks for your input.

 

X2. I want to know too. I just ordered a flashpaq to replace my hypertech, but I'm sure I'm still gonna want some more power. I drive mine on the highway waaay too much. I don't get to go offroad nearly enough, so I want to do a few little things to make it a little more comfortable/powerful on the road.

 

Look at the RPM vs tire size charts in the Modified FAQ section.

If you want slightly more bias towards crawling go with the 5.38s, but if you want a great choice for excellent highway performance and good off road drivability go with the 5.13s.

One of the issues is "How high do you want your RPM to fly up to when you are on the highway driving at 70-75 MPH and you drop out of OD?"

IMO, the 5.13s are an excellent match for the auto and 35" tires for all around great performance.

 

Start with the suggestions and RPM chart in the FAQ's.

Then move on to the other 1000 threads concerning re-gearing.

For an auto with 35's:
4.88's at a minimum
5.13's for a bit more power (the mpg difference from 140-something rpm is negligible)
5.38's if you have a Rubi and live in mountains or want the extra gearing for offroad or plan to go bigger after the 35's wear out or...

 

I would go 5.38's without a doubt. Not even a question. I already drive my vehicle without overdrive which I beleive is effectively a steeper final than a 5.38. I see people say the 5.38 would be better for wheeling which is funny cause in 4low she has plenty of power, climbing a grade at 65mph is where she needs help. If I could put my rpms around 2800 at 70mph that would be perfect imo. It's only because they dont make a steeper gear set which makes me afraid to roll larger than 37 inch tires with my automatic.

 

If you go with 5.38's and think the rpms are to high you can always go to a bigger tire.

 

I went with the 5:38's on my Rubi Auto w/35's and love them!!!!

 

How does it do going up to flagstaff or anywhere else in the moutains? I went to flag this past weekend and I am regearing at tax time. I only have a x so 5.38s are out but I am undecided about 4.88s or 5.13s.

 

good God do a search.....this is brought daily by someone..

 

If gas mileage is a non issue and you want your rpms around 2800 at 70 then the 5.38s are your gears. you will need to retune and recalibrate your throttle response. and you will have plenty of power to even spin the 35s if you would like.