The 4.88 gives slightly over 2700 in 5th gear at 70 mph. Guess I am used to different engines. Have had two JK's that run 1700-1800 at highway speed in OD.
Proper Gear Choice
- Thread starter Serbonze
- Start date
Be very cautious with the tire size you plug in. The calculator works on the exact tire radius when measured from the center to the ground or the rolling radius. If you plug in a 35" tire, that is typically not the rolling radius doubled. For 35's, I typically plug 34".
The way I discovered that is I had a lot of folks ask me about the 32RH and gearing for 35's. When I told them it ran 3000 rpm at 68 miles an hour based on all the ones I had done, they told me the calculator was screwed up. I explained that it worked off of simple math and it can't be wrong so their input had to be wrong. Since I knew the specifics of several, I kept changing the tire size until it matched and it wound up being about 1"ish smaller than you would think.
It's also useful if you want to find your rolling radius, just keep changing the tire size until the RPM at a given speed match what you see in your rig.
Proper Gear Choice for a DD should drop your rpm in OD far below the peak torque/horsepower. OD should be used to drop rpm, quiet the ride, extend the engine life, reduce wear. All modern cars do that. The Audi 8speed transmission hits top speed in 5th gear because the extra 3 gears drop rpm for all those reasons AND to deliver better gas mileage. Same with Jeeps little Renegade with the 9speed. I think it hits top speed in 6th gear.
Off road, Trail dedicated sure build it to stay in that peak 2700rpm range but for a daily driver gear it to cruise closer to 2000rpm. And drop a gear or two when you need more power. Driving my TJR with 33s, Yellowknife to Denver, 2200miles, I was cruising on the Interstates all day at 75mph, 2700rpm... horrible.. 15mpg. Made me want my old YJ with the 3.07s which did the same trip in 4th gear at 2300rpm... 22mpg. 100gallons of gas vs 150gallons of gas.
Lots of the advice on these forums comes from guys who do the extreme off road stuff. Some of those guys also trailer that Jeep. But some of us actually only own a Wrangler which we use everyday for everything. When seeking advice be sure to research the source too.
Off road, Trail dedicated sure build it to stay in that peak 2700rpm range but for a daily driver gear it to cruise closer to 2000rpm. And drop a gear or two when you need more power. Driving my TJR with 33s, Yellowknife to Denver, 2200miles, I was cruising on the Interstates all day at 75mph, 2700rpm... horrible.. 15mpg. Made me want my old YJ with the 3.07s which did the same trip in 4th gear at 2300rpm... 22mpg. 100gallons of gas vs 150gallons of gas.
Lots of the advice on these forums comes from guys who do the extreme off road stuff. Some of those guys also trailer that Jeep. But some of us actually only own a Wrangler which we use everyday for everything. When seeking advice be sure to research the source too.
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You should really knock that some of that off. Some of us giving the advice have rigs we haul on trailers to do the extreme offroad stuff and that trailer and rig happen to be parked beside a bone stock 2004 TJ Unlimited, an 04 TJ on 33's with 3" of lift on 33's with the 42RLE and 4.88's, an 01 TJ on 35's with an AW-4 out of an XJ and 5:38's, and a bone stock XJ with the AW-4 and 3.73's.
I've also had 4.10's with 33's and the 32RH, 4.10's with 35's and the 32RH, 4.56's with 35's and the 32RH, and 3.73's with the 42RLE on 33's and 35's.
I'm also not myopic enough to confuse a sports car with a Wrangler and the difference in wind resistance is enough to blow any gear ratio correlation between the two right out of the water and into oblivion.
You can take a TJ on 35's and increase the MPG average by 5 MPG simply by keeping the speed on the highway at 60 mph due to the decrease in wind resistance and the fact that the increase by going faster is not linear.
LIke I and others have said, you should have personal experience with the 42RLE before continuing to give your improper advice and opinions on gearing for the 42RLE which you have no personal experience with. And my TJ with its 42RLE has never been trailered, it's driven everywhere I take it.
Your guesses on the proper ratios for the 42RLE are just that, guesses. Incorrect and baseless inexperienced guesses to be more precise. With more experience you would have already realized that proper ratio choices for the AX-15, AX-5, 32RH, NV3550, NSG370, etc. don't work where the 42RLE is concerned.
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I know it has been said over and over but until you've driven one close to or right at stock, it's hard to understand the 1000 rpm drop down to 2000 rpm at 70 and the crap trans that won't downshift, and in OD, if the road even remotely hints that it is going uphill, the rig won't pull it and you keep giving it more gas, it won't shift, more gas, won't shift, and then when it does, it goes into 2nd instead of drive and your RPMs are through the roof.
UPJOHN
TJ Enthusiast
I have 3.55s, with an ax15. Mine came with 30s and now has 31s. My TJ has to be the easiest manuals I've ever driven. I can start off in second gear, and it feels the same as 1st gear in my old 4cyl with 4.10s and ax5.
badlieutenant
TJ Addict
Just my own personal experience:
Now, after 3 months wheeling about as hard as I care too, commuting to work, as well as 300 mile trips to see the boy in college in the Appalachian mtn's I can say that the 4.11 choice for my 4.0/NV3550 on 33's is just about perfect. I usually cruise at 70 (gauge is off by 2 according to my gps) on the hiway, and coming DOWN the mountains on I-40 at Asheville I can slip up to around 80 and maintain as long as there's a negative grade, but aerodynamic resistance really work against me above 70 on flat grades. I can even maintain 70 on slight positive grades in 5th gear.
Off-road I don't feel I have any diminished capability (personally...based on the group I wheel with), but this is East coast wheeling, and many here on this forum may not understand the difference. We don't have uber-grippy surfaces that really require an intense crawl ratio. Here, you kinda "pin it to win it" to sling the red clay out of your tread to get traction (see my license plate for my opinion on that) then let off and idle over the obstacle.
Mine spends 80% of it's time on the road. and 10% of THAT time my bride and or my kids are with me. I've got HS age girls, and they don't have issues with getting in, but my bride grunts on occasion with the elevation struggle, even at a slender 5'-7" she would have preferred a stock height. Which is a big reason I stayed at the 4" lift and 33's. The OTHER reason is, I wheel with guys that roll mostly 35's and 37's but I've never been left behind, or had to be helped thru any of the trails moreso than the others. So I don't regret NOT stepping up to 35's
I ALMOST went with 4.56's. I researched and calculated till I was blue in the face. I made my own spredsheets as well as studied all the ones on jeepforum, and the major gear mfgs, as well as took extensive data on MY driving habits, and what would be ideal rpm for my driving. A big fear after changing my mind to 4.11's FROM 4.56's was; would I regret the 4.11's?!?!?! And then....would I ADMIT that defeat if it was true? But after driving it now on all roads, and speeds I feel like that was best choice for me. I'm not over-reving on the hiway, and I'm not lugging at low speeds. If this were ONLY a trailer queen, then it'd be 4.88's on 35's without question, but since this is a do-everything serve-every-need kinda vehicle, 4.11 with the NV3550 was just right for my application.
Now, after 3 months wheeling about as hard as I care too, commuting to work, as well as 300 mile trips to see the boy in college in the Appalachian mtn's I can say that the 4.11 choice for my 4.0/NV3550 on 33's is just about perfect. I usually cruise at 70 (gauge is off by 2 according to my gps) on the hiway, and coming DOWN the mountains on I-40 at Asheville I can slip up to around 80 and maintain as long as there's a negative grade, but aerodynamic resistance really work against me above 70 on flat grades. I can even maintain 70 on slight positive grades in 5th gear.
Off-road I don't feel I have any diminished capability (personally...based on the group I wheel with), but this is East coast wheeling, and many here on this forum may not understand the difference. We don't have uber-grippy surfaces that really require an intense crawl ratio. Here, you kinda "pin it to win it" to sling the red clay out of your tread to get traction (see my license plate for my opinion on that) then let off and idle over the obstacle.
Mine spends 80% of it's time on the road. and 10% of THAT time my bride and or my kids are with me. I've got HS age girls, and they don't have issues with getting in, but my bride grunts on occasion with the elevation struggle, even at a slender 5'-7" she would have preferred a stock height. Which is a big reason I stayed at the 4" lift and 33's. The OTHER reason is, I wheel with guys that roll mostly 35's and 37's but I've never been left behind, or had to be helped thru any of the trails moreso than the others. So I don't regret NOT stepping up to 35's
I ALMOST went with 4.56's. I researched and calculated till I was blue in the face. I made my own spredsheets as well as studied all the ones on jeepforum, and the major gear mfgs, as well as took extensive data on MY driving habits, and what would be ideal rpm for my driving. A big fear after changing my mind to 4.11's FROM 4.56's was; would I regret the 4.11's?!?!?! And then....would I ADMIT that defeat if it was true? But after driving it now on all roads, and speeds I feel like that was best choice for me. I'm not over-reving on the hiway, and I'm not lugging at low speeds. If this were ONLY a trailer queen, then it'd be 4.88's on 35's without question, but since this is a do-everything serve-every-need kinda vehicle, 4.11 with the NV3550 was just right for my application.
Agreed !!
I had a Sport LJ Automatic for 2 months. Bought it because it was automatic so my wife could drive it too. I absolutely hated it. I'm not a fan of automatics cost, maintenance, reliability anyway but that 4speed, the OD even with stock rubber was awful... even with the 3.73s. And my wife prefers "cars" AWD but she prefers a "car" even over an SUV. Me I hate "cars".
So yeah, big fan of the clutch. But the 3speed automatic is a great tranny. I could live with that one. I would not miss overdrive.
That said and given the OPs question.... Are 4.10s worth the cost?
33s thru 3.73 2280rpm at 60mph. VS 4.10s no OD 2500rpm.
At 75mph... 3.73.. 2800rpm......... VS 4.10.. 3100rpm.
I'd keep the 3.73 for a DD.
It's hard to believe that it's been this long, but I wanted to close the loop on my original post.
I was lucky enough to get a hand me down a Dana 44 ARB locker last year. The locker is the RD116, which wouldn't work with my 3.73 gears based on the carrier break. That free locker kind of snowballed into a much larger project. It took some time, but I eventually I ended up buying an ARB front locker to match and Revolution 4.10 gears and master install kits to match from Allen at @AOR.
I've only had the Jeep back for a day, but I can without a doubt say that I noticed an immediate difference when taking off from a stop and trying to get into traffic. I need to follow Revolution's break in procedure so I'll be babying it for awhile, but based on the around the town driving yesterday I'm extremely pleased with the change from 3.73 to 4.10.
Thank you to all for the feedback (through several different posts) on both locker selection, gear ratio selection, and gear brand selection.
I was lucky enough to get a hand me down a Dana 44 ARB locker last year. The locker is the RD116, which wouldn't work with my 3.73 gears based on the carrier break. That free locker kind of snowballed into a much larger project. It took some time, but I eventually I ended up buying an ARB front locker to match and Revolution 4.10 gears and master install kits to match from Allen at @AOR.
I've only had the Jeep back for a day, but I can without a doubt say that I noticed an immediate difference when taking off from a stop and trying to get into traffic. I need to follow Revolution's break in procedure so I'll be babying it for awhile, but based on the around the town driving yesterday I'm extremely pleased with the change from 3.73 to 4.10.
Thank you to all for the feedback (through several different posts) on both locker selection, gear ratio selection, and gear brand selection.
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ridinsurf66
Member
33s, 4spd auto... 4.88 is perfect, that OD is so steep it is like the stock Rubi 6speed with 4.10s.
I'd consider 5.13 perfect for the street and highway for that combination. Of course it'd be superb for offroad too.
6 speed is 2950 in Drive at 70, auto is 3500 at 70.
OD is the same and you are correct, it is terrible.
Auto is 3500? What transmission or tire/ratio combination were you thinking of Blaine?
While this thread is still alive.. I'd like to sneak in a question.
2005 6 speed Tj, what is the best gear ratio for 33 inch tires? Currently at 3.07.
I want it set up for daily driving with good mpg.. but able to run the Rubicon trail and perform well offroad.
2005 6 speed Tj, what is the best gear ratio for 33 inch tires? Currently at 3.07.
I want it set up for daily driving with good mpg.. but able to run the Rubicon trail and perform well offroad.
4.56 would give 2725 rpms at 70 mph, 4.10 would give 2450. I personally would rather run 2700-2750 at 70 mph as I did when I ran 4.88 with 35" tires and my previous 5-speed manual. I only get approx. 2625 rpms now at 70 mph with my 5.38 gearing and 42RLE transmission and I wish I could have gone for a slightly lower ratio for a slightly higher rpm but 5.38 is as low of a ratio as I can install into my Rubicon Dana 44 axles.
So if it were me with your 6-speed and 33's, I'd go 4.56.
So if it were me with your 6-speed and 33's, I'd go 4.56.
ridinsurf66
Member
How do you like the performance on the highway?
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