I haven't seen these on this forum yet, if I missed it please delete.
Tire Size Gear Ratio Charts
- Thread starter JerryD
- Start date
Personally, I use this- not taking away from the charts, but there are also other variable to consider as well.
OP
Yup, that is much more granular and precise. I like to show the charts to people who ask "do I really have to regear" to illustrate the impact regearing has.
OP
Yeah, like "are you in Kansas or Colorado" among other factors
Right on man! I was in no way trying to sharpshoot- I definitely appreciate you posting the charts to help answer the age old question!
Looks like the chart is pretty accurate. I plugged in the tire size, transfer case, etc into your link and it differs by 1 rpm from the chart above.
I just had my '07 JKU re-geared from 4.10's to 5.13's (42RLE transmission) on 35's and it is soooo much better. Have a pretty steep 7 mile long grade between work and home and with OD off she'd huff and puff switchin gears and shootin up RPMs to try and get up that sucker....going 55.... It was the worst.
So I bit the bullet and went with Motive 5.13's and Eaton Truetracs front and rear (I don't do a lot of hard technical rock crawling to need a full time locker) and maaaaaan. Night and day difference. Transmission is shifting great, she's pulling the grade at 65mph no problem, and I'm sitting around 2200-2300 rpm at 65-70ish on the flats.
My freaking gas mileage even got better.
Only thing I've enjoyed as much as this is the PSC big bore kit I put in. Probably my two best mods so far.
Right on! I remember when I re-geared to 4.88s with my NSG370 and I only regret not doing it sooner! I live in SC, but in the blue ridge mountain area and the inclines were killing me! I'm hoping the 37s will help my gas mileage (as I'm a little too deep for my current 35s), but based on the link, I should be good to hook.
Extremely happy we all came together to help one another out with good info.
Alex Bunker
New Member
OP
You want to go to a smaller tire? That's unusual for a Jeeper...
OP
I did. I just went from 35's to 315 75 R17 a few weeks ago. Weight savings & cost savings... but mostly availability. That said, I may go back to 35's in the spring.
Like the other OEMs, the CAFE standards have to be factored into the equation. Since the large majority of Wranglers will never leave the road 3.21 coupled with the 5-spd gearing is perfectly acceptable. I find mine (with 32's) to have no driveability issues for street use. Certainly going larger diameter or depending on the type of off-road usage and that changes things...