I'm currently running 35" tires on an 2011 automatic. I'm going to regear in the near future.

I know the recommended ratio is 5.13, but checking the charts 5.38 is in the optimal range for 35" and 37".

What would going with 5.38 do compaired to 5.13? If I plan on putting 37's on in the future, would it be ok to go with 5.38 now so I won't have to regear later?

or is this a bad idea...

 

If you have a rubicon then 5.38 is an option for you and cause you have an auto i would reccomend it. If you dont have a rubi then , despite the fact that some company makes 5.38 for the d30, i would stick with 5.13s.

 

Is the cost similar regardless of which one I go with? I was quoted off the cuff in the ballpark of $1k per axle. Not sure if it varies much. I have Rubi so was looking at 5.38.

 

IMO I wouldn't go 5.38 unless you going to make it a dedicated off-road buggie. Also look around 1k per axle is on the HIGH side.

 

I would do the 5.13's for 35's. The 5.38's having finer teeth are also more likely to break and you will get even worse fuel economy...

 

I went 5 38 and did it again after I broke the rear. Everyone says the pinion is to small but I broke my ring gear not pinion

 

I also will add I beat the heck out of my jeep. I have not had a problem since and it was a new install when it broke the first time. Ben over a year now and I run 38s now 35s then

 

You have a 6spd, he has an auto. Completely different transmission gearing. (plug some numbers into the rpm charts in the faq's. Given the same axle gearing, you will need to run tires that are about 5" taller than him to run the same freeway rpm's.)


The fuel economy depends, it's all about the ability to hold overdrive. Yes, it's higher rpm, but that extra rpm (and hp) let's me hold OD longer before dropping down. Shifting in and out of OD trying to maintain freeway speeds is the mpg killer, not the extra 100 rpm. At least that is my experience with it.

 

So an automatic 6.5 long arm with 37 inch tires rubicon that gets alot of highway use and alot of off road... 5.38?

 

WOuldnt 4:88's be better for a Pre Pentastar Automatic with 35 in tires?