I just assumed that when the Jeep would drop into its OD gear that was the prime RPM as designed by the manufacturer. Never knew it was far from it due to them re-gearing for better EPA figures.
Most of the advice is for rock crawling. For mud you actually want wheel speed and a taller ratio than the rock crawlers.
yep, pushing on the gas pedal in the wrong gear will suck gas like crazy with zero acceleration. Best way to avoid that, take yer shoes off and you will feel the pressure and down either lift off or down shift.
First post and a Jeep noob (but learning fast)! Great info in this thread (just read the whole thing--thanks all) but looking for clarification: 2000 manual 4.0 w/3.07 gears currently, looking to upgrade to 33s when my DuraTrac 31s wear out to fill in that 4" (I think) lift. I know the above is a recommendation for an AT. For a 5-speed manual I'm gathering that a one-step higher ratio is a better? 4.56 for hwy-centric driving, 4.88 for offroad-centric? Am I close? Looking for balance--eg: road trip from OR to Moab, roadin,' then back again. Might try 35s later on or as a second set..
pretty much on the money. if you are going to 35s later, go 4.88s now. I take it this is not a daily driver?
Thanks jjvw. That's likely where I'll end up. Versatility is key for me and I get the impression 33s and 4.88 gearing are a bit of a sweet spot in that regard, though 4.56 pulls at me from a mileage perspective. If anyone has experience with that configuration (4.56 on 33s, or even 4.56 on 35s) I'd love to hear about it. It'll be interesting to see where the change takes me with regard to acceleration because even at 3.07 on 31s it doesn't feel underpowered to me--this Jeep wants to go. I suppose 4.0L + smaller tires explains that, as billybob suggested. I'm definitely going to have to get used to shifting at higher rpms per recommendations on this thread because my ears tell me to shift at 2000-2200. Hard habit to break! More power and potentially better mpg is plenty good motivation though.
456, 33’s, 6Speed. I’m naturally a little lower geared than the 5Speed. I love, love, love these gears. I think you’ll love 488
4.56 on 31s here with 5spd. Same as you, my ears tell me to shift around 2k-2200. Got used to shifting 2500-3000. I’m glad I went deeper gears last minute as I almost went with the more common 4.10 for 31s. I haven’t calculated mpg yet but I feel it did get worse than when I had 3.07. Gas gauge def moves quicker towards empty haha but I admit I do drive it with a heavy foot post regear. Plan is to go 32s most likely next set of tires in a few years
Good thought--might be the clincher for me, especially since I'll be around town a lot more than I'm on the freeway (on the weekends, mostly). I'll have some time to think about it while I wear out these 31s and adjust my driving style. In the meantime new shocks because these are stiff as a brick. Feels like I'm driving the old International Harvester pickup I rocked as a teenager with an empty bed. Really appreciate all the feedback.
My experience, 2 TJs, 2 YJs, 4 other Jeeps, in a 4.0L TJ, 2K rpm delivers fuel economy, 3K rpm is where power starts. The smaller the engine or bigger the tire, the narrower that window between economy and power gets. Or the bigger the engine the bigger the spread can be.