Tazer JL - more than just a tire size programmer!

[CarbonSteel]

I have 4.88 in my JLUR on STT Maxx 37's and 2100 rpm running 70 in 8Th sounds about right. speed limit around here on the interstate is 75 and I normally run about 2100-2300 RPM. in 8th. With the stock 4.10's I would sit in 6th and I would have to manually shift it into 7th and depending on the wind it would be happy there. If I manually forced it into 8th it would kick it back down to 6th.

It is about the same for mine, just slightly higher RPMs (maybe 2300-2400) at 75MPH, but that is likely due to the BFG K02'S being a short 37.

Sponsored

 

[Zandcwhite]

It is about the same for mine, just slightly higher RPMs (maybe 2300-2400) at 75MPH, but that is likely due to the BFG K02'S being a short 37.

It all comes down to use. We do a lot of road trips through states that have speed limits of 75-80mph. Most times the cruise is set at 85mph+. With our 37’s and 4.10’s it holds 8th at those speeds no problem as we are in the 2100-2300 range. On 4.88’s we’d be pushing 2500-2800 rpms. At the speeds we drive regularly, we would lose fuel economy (or be forced to slow down). The 4.7-1 1st gear and 4-1 transfer case mean plenty of gear reduction off road. I could see 4.56 as a happy balance on 37’s for speed and a little more 8th gear at lower speeds, but the benefit of 1 gear ratio isn’t worth the expense in my opinion. Some guys swear you need 5.13’s with 37’s, but 2400rpms at 75 just doesn’t sound efficient to me.

 

[CarbonSteel]

It all comes down to use. We do a lot of road trips through states that have speed limits of 75-80mph. Most times the cruise is set at 85mph+. With our 37’s and 4.10’s it holds 8th at those speeds no problem as we are in the 2100-2300 range. On 4.88’s we’d be pushing 2500-2800 rpms. At the speeds we drive regularly, we would lose fuel economy (or be forced to slow down). The 4.7-1 1st gear and 4-1 transfer case mean plenty of gear reduction off road. I could see 4.56 as a happy balance on 37’s for speed and a little more 8th gear at lower speeds, but the benefit of 1 gear ratio isn’t worth the expense in my opinion. Some guys swear you need 5.13’s with 37’s, but 2400rpms at 75 just doesn’t sound efficient to me.

LOL - no way I would see 8th gear (not even 7th) or 2100-2300RPMs with 37's and 4.10 gears. I didn't see that with 35's.

With a 3.6L and 37's, 4.88 is the sweet spot for me. Your mileage may vary.

Sponsored