Can anybody, expert or otherwise, give me the low down on the gearing and difference running the Cooper STT 33" and the 35" same brand tire please.....there is only about 1.11 inches difference in size there according to Coopers website and the 35's are about a pound and a half heavier. Doesn't seem like much but until I have the opportunity to re-gear I'd like to go ahead and get the tires and run them for a while, although I want to be able to travel fairly normal and not bog down my JK. Was just interested if anybody has gone up in size without regear and how painful life was afterward. FYI 3.73 is what I'm running on an 08

 

There are about a thousand gearing threads to read through for opinions, but what it really comes down to is your own personal opinion of the performance. The JK specific gear charts (broken down by engine and transmission, not the generic ones) are easy to find online with a quick search. Find them and plug some numbers in to see where your rpm's will be compared to where they are now. Some people are ok with 35's and stock gears, others aren't. I didn't like 3.73 with the stock 32's that came on my 08.

One little item worth noting is that you have a button down by the shifter that turns off the overdrive. If you pull up the rpm chart and do a little basic math, you will find that pressing that button will bring your rpm's up real close to 5.38 gearing. (meaning: for a 3.8 auto, the rpm's for 35's with 3.73's and OD Off is roughly equal to 35's with 5.38's and OD On) Doesn't help much around town, but should make it more livable on the freeways until you get around to gears...

 

I didn't pull out the scale but my 285 coop stt's 'felt' lighter than 275 goodyear mtrk's.

Where I'm going is that while it may be a 35, it may not be as heavy as other contenders, albeit not as light as the all terrain tires.


3.73, 285 stt's, and the 6 speed isn't unbearable at all- no plans at all to regear. If you're short on cash then go with the smaller tire to avoid bigger problems with bigger tires.

 

Yea I was hoping someone in the forum world had already done what my plans are and could just give a more personal review. I'm not super crazy about driving around with the OD off but that's an option for sure if I go this way first. I appreciate the input guys it sure beats scouring this forum and reading the 10 million threads on the personal re-gear dilemma. I have the gearing chart you speak of and while it does in fact do just that...it's still a lot different seeing something on paper and "feeing" it different (good or bad) in person and for me there's really no comparison. Guess I either need to just stop bitching and get the tires and deal with it or ultimately wait and re-gear and tires all at once but man that's a hit to the wallet for sure.

 

Do you have an auto with the 3.8? What elevation and elevation changes on your typical drives? Do you like to launch like a sports car? I ran STTs skinny 33's and lost very little off the line; lost 2 mpg although I have 4.10's. Now running 35's but can tell I lost acceleration and mpg. I run sea level to 2,000'. OD is off always: 65 mph ~ 2900rpm.

 

SO an '08 with 3.73's. What trans? A/T or 6-speed? Honestly, either way with 35's you'll still be okay for a while. It won't be a rocket by any means...but then again...it's a Jeep. When I initially did my lift and 37's (Nitto Trail Grapplers) I was on stock 4.10's and it was my daily driver traveling about 30 miles each way in moderate traffic. Wasn't unbearable, but a gear change was definitely in my future. Didn't really have any issues at slow wheeling speeds off road, either, but again, taller gears would've definitely helped.

Of course now I've since regeared to 5.13s, which actually should've probably been 5.38's, but it's much better than it was. For 35's, I'd say probably consider gearing to 4.88's and calling it good. As long as you don't plan to go higher on tire size later. Again, it won't feel the same as stock with 35's, but until you have the money/time to regear, it's bearable.

Just my thoughts, though. Worth exactly what you paid for it

 

I wanna say for the 3.8l, if auto trans the 5.13 is the most recommended for 35s and for the manual trans then the 4.88 for 35s.

 

This won't work. It'll throw your computer off and kick the ESC in, especially since this is an automatic. You will need to reprogram for the correct tire size.

 

Hm. I never had that issue. I drove around with OD off a lot especially on long trips on interstate. Are you saying you need to reprogram for correct tore size first before running with no OD?

 

hahaha... boy, I need more coffee (or less)... not sure which. I read that as Odometer being off... not Over Drive being off... geesh!