Are 33's bad for 3.07 gears?

[billiebob]

I have this setup except with a manual and on 31s (going to 33s next round) and it really is a blast on forest roads--feels like a 4WD race car. There are tons of forrest roads around here in the Oregon Cascades--literally everywhere and way more than there are rocky trails. I have to drive an hour or two for any of that stuff many of you love and life is busy. I've been planning for upgraded axles, ox lockers, and a regear to 4.56 or 4.88 but now I'm torn because the fun with the current setup is so accessible and plentiful. I'm starting to think I need a second Jeep

Honestly, with 33s while I loved 4LO and 3.07s, and I got 25mpg on the Interstate, I never used 5th in 2HI, My use is similar to yours and I now have a Rubi on 33s so 4.10s but I wish I had 3.73s. I think 3.73s are the best all round ratio for 33s with a clutch.

 

[billiebob]

15 x 7 that was meant to say!

yes, you can..... heres 33x10.50R15 KO2s on 15x7 stock steel spokers. 5.5" backspace and AEV Highline. 4" flares.
Stock suspension, no lift.

3.73s and 33s is the best all around ratio, I have 4.10s and they are too deep for a daily driver. I put 24K miles a year on mine and I tow a trailer in the mountains for half of those miles. If your TJ is strictly a weekend off roader,,,, maybe you'll want deeper gears but 3.73s are a great ratio if your TJ sees a lot of pavement.

 

[Goatman]

Why would never using 5th gear be ideal for 33s? 4.10s and getting better low and high speed performance seems to make more sense to me.

 

[YourWorstEnemy]

15 x 7 that was meant to say!

Absolutely you can but the gearing would be not ideal...although Discount tire will not touch them if you have 7 inch wheels....run 12.5s on 6 and 7 inch wheels many times no issues just get your air pressure right for the tire patch...they hold the bead really well too

 

[YourWorstEnemy]

Gearing is so subjective....many are fine with 3.73 and 33s...if you have a manual you can pick what gear and when and never use OD...an auto is a bit more noticeable on power loss...ran 33s in a 2006 Rubicon with the auto and 4.10s and had to drive with OD off all the time because it was too deep and would not pull a hill

 

[RitualHabitual]

Honestly, with 33s while I loved 4LO and 3.07s, and I got 25mpg on the Interstate, I never used 5th in 2HI, My use is similar to yours and I now have a Rubi on 33s so 4.10s but I wish I had 3.73s. I think 3.73s are the best all round ratio for 33s with a clutch.

Nice to hear an alternative perspective. I basically don't use 5th in 2HI either. I drove to Portland on I-5 a couple weeks ago and kept it in 3rd the whole time hoping the extended time at higher RPMs would clear up a lifter tick. That made for ~3000rpms at 70+mph. I'd have to be going 85-90 for 5th to make sense--talk about overdrive! Haha I bet that will totally exasperate a few of you guys Just where I'm at until I make some drivetrain decisions.

Seems like the 4.0+manual combo gives you a whole lot of flexibility. I know 3.07 is the dreaded ratio in the forums, but the hate doesn't resonate because it honestly does not feel underpowered to me with a manual--quite the contrary in fact--and it doesn't feel like I'm bogging even in 2HI/1st. In other words, I ain't suffering (even if it is less than ideal)! I am on 31s though--maybe 33s will change all that (I'll know soon enough). All depends on how you use your rig, I guess. I'm just not very interested in rock crawling for rock crawling's sake. I just want to roam with confidence. I'm even considering a Super 35 upgrade rather than going to a Dana 44--another highly unpopular setup Call me crazy.

 

[Goatman]

I don't think 'hate' is the right word concerning any gear ratio. At least for me. You do you. But if you ask a question you have to expect an answer that may be different than what you think.
It makes no sense to me to have a 6 speed trans but only be able to use 1-3. You are leaving so much performance on the table. If you think 3.07's with 35s give you all the power you need, than hey, knock yourself out. Just don't ask my opinion on what gears would be best.
Try putting on some 29s or 28s and see if you like that better. You can see for yourself if that is more driveable.

 

[Fouledplugs]

Nice to hear an alternative perspective. I basically don't use 5th in 2HI either. I drove to Portland on I-5 a couple weeks ago and kept it in 3rd the whole time hoping the extended time at higher RPMs would clear up a lifter tick. That made for ~3000rpms at 70+mph. I'd have to be going 85-90 for 5th to make sense--talk about overdrive! Haha I bet that will totally exasperate a few of you guys Just where I'm at until I make some drivetrain decisions.

Seems like the 4.0+manual combo gives you a whole lot of flexibility. I know 3.07 is the dreaded ratio in the forums, but the hate doesn't resonate because it honestly does not feel underpowered to me with a manual--quite the contrary in fact--and it doesn't feel like I'm bogging even in 2HI/1st. In other words, I ain't suffering (even if it is less than ideal)! I am on 31s though--maybe 33s will change all that (I'll know soon enough). All depends on how you use your rig, I guess. I'm just not very interested in rock crawling for rock crawling's sake. I just want to roam with confidence. I'm even considering a Super 35 upgrade rather than going to a Dana 44--another highly unpopular setup Call me crazy.

The only aspect You didnt mention is whether you have driven a TJ, manual or auto, with 31’s or 33’s with 4.56, 4.88, or lower. It’s often one of those things that you wont really notice what your missing out on until you've tried it.

 

[AndyG]

The only aspect You didnt mention is whether you have driven a TJ, manual or auto, with 31’s or 33’s with 4.56, 4.88, or lower. It’s often one of those things that you wont really notice what your missing out on until you've tried it.

That is the gospel truth .

 

[RitualHabitual]

The only aspect You didnt mention is whether you have driven a TJ, manual or auto, with 31’s or 33’s with 4.56, 4.88, or lower. It’s often one of those things that you wont really notice what your missing out on until you've tried it.

I admit that I haven’t and definitely don’t know what I’m missing (ignorance is bliss?). That’s what’s hard about these decisions when you’re not a veteran Jeeper—you’re looking at dropping a bunch cash and changing the nature of your driving experience without knowing how it’s going to be—kind of a leap of faith. I trust ya’lls knowledge and experience. It’s just nice to hear some alternative perspectives. I’m driving a 5-speed so I’m only missing one gear. I’ll definitely go to deeper gears, but I’m enjoying the thing the way it is while I figure out just how deep I want to go. Hopefully I’ll get to experience 4.56 to get an idea what that’s like at some point. Testing out smaller tires is a good idea too—hadn’t thought of that. Thanks for the feedback!

 

[xxdabroxx]

The whole 3.07 gears are fine with 33" tires argument is like saying I took out 2 spark plugs and the engine still runs so why would I buy the extra two spark plugs.

 

[AndyG]

I admit that I haven’t and definitely don’t know what I’m missing (ignorance is bliss?). That’s what’s hard about these decisions when you’re not a veteran Jeeper—you’re looking at dropping a bunch cash and changing the nature of your driving experience without knowing how it’s going to be—kind of a leap of faith. I trust ya’lls knowledge and experience. It’s just nice to hear some alternative perspectives. I’m driving a 5-speed so I’m only missing one gear. I’ll definitely go to deeper gears, but I’m enjoying the thing the way it is while I figure out just how deep I want to go. Hopefully I’ll get to experience 4.56 to get an idea what that’s like at some point. Testing out smaller tires is a good idea too—hadn’t thought of that. Thanks for the feedback!

go out and drive a stock Jeep with stock tires and you'll get the same experience as 33 inch tires with 456 or 35 with 5:13....

Regearing is not a modification and it's not a hop up... It is a corrective measure to restore the ratios and get the engines output in harmony with the driveline.

Be sure to submit your regearing application early... The Forum Regearing Committee usually fills up each quarter within 30 days.

 

[WallyWest]

Be sure to submit your regearing application early... The Forum Regearing Committee usually fills up each quarter within 30 days.

LOL!!

 

[Daz7]

The whole 3.07 gears are fine with 33" tires argument is like saying I took out 2 spark plugs and the engine still runs so why would I buy the extra two spark plugs.

Well yes and no.... I've had a 4.56/33's setup TJ and 3.07 standard tyre/32" tyre/33" tyre setups. Thinking about this it appears the guys with manual transmissions can live with things far better than the auto guys because they can manually adjust the ratios they are using instead of the auto hunting around or wanting to change up to a taller gear constantly.

FWIW with my current 3.07 and 33's setup, at highway speed in 4th (it's a 6 speed) I'm more or less at the same RPM's as a TJ with standard tyres. Conversely, I'm getting a little sick of how it takes off from a standing start in 1st and complete lack of low range downhill control.

I keep going around in circles with regard to what to do so have done nothing apart from buying gears. At 180000km's I haven't touched the diffs/bearings etc and keep thinking do I rebuild the 44/30 setup or throw cash at it and just buy a new Currie 44 for the front already setup and be done with it. Procrastination at its best.

 

[xxdabroxx]

Well yes and no.... I've had a 4.56/33's setup TJ and 3.07 standard tyre/32" tyre/33" tyre setups. Thinking about this it appears the guys with manual transmissions can live with things far better than the auto guys because they can manually adjust the ratios they are using instead of the auto hunting around or wanting to change up to a taller gear constantly.

FWIW with my current 3.07 and 33's setup, at highway speed in 4th (it's a 6 speed) I'm more or less at the same RPM's as a TJ with standard tyres. Conversely, I'm getting a little sick of how it takes off from a standing start in 1st and complete lack of low range downhill control.

I keep going around in circles with regard to what to do so have done nothing apart from buying gears. At 180000km's I haven't touched the diffs/bearings etc and keep thinking do I rebuild the 44/30 setup or throw cash at it and just buy a new Currie 44 for the front already setup and be done with it. Procrastination at its best.

I had 3.07/33" with the 5 speed when I bought mine and I didn't use 4th or 5th. Seems to me that 2nd gear is about equivalent to what 1st was based on memory.

Based on grimm jeeper, 2nd is a little taller than first used to be. (3.07 left, 4.56 right)

 

[BugoutJeep]

For the off-roading I do just around the farm, mud tires are a must, so I want to make sure of that stipulation. With 3.07s, AX-15 and 29" mud tires, I'd be fighting 3rd and 4th to stay around 60 mph on the highway with my old 4.0L. I could use 5th going down a steep hill.

With a less aggressive tread 33" tire with the same setup I could watch my fuel gauge drop if I tried to maintain highway speed in 5th only, so well under 10 mpg. Any towing and most off-roading with 3.07s and 4Lo (2.72), means smelling the clutch. It's fine on rough easy terrain with little chance of getting hung up.

With the R2.8 and as loaded as my Jeep is now, 3.07s are not terrible, but not ideal. I'm going 3.73s and Atlas with at least a 5:1 gear ratio. With 5:1 I still would prefer to go slower at times, but that's pretty good vs the effort of making a 4 speed t-case fit or swapping to a different transmission. I think 3.73s for my rig will be just about perfect for the highway, but off-road I'd rather have more. If one was running with less gear and no rack then 3.55s would probably be very good for the R2.8 or those occasionally dropping to smaller tires. Some really like 4.10s and that wouldn't be bad for this engine. But the 3.07s on the highway and with the rack I have to keep my MPH up to get my RPMs up and on steep hills I'm just shy of having enough torque without using a lot of throttle and you can't let the turbo get bogged down when you're going down a hill and then trying to go up a hill at around 1,600 rpms. With all of that, since I added the rack my mpg dropped about 20%. I figure about 15% drag and 5% from the gear ration, but just a guess.

I can't wait until I can ditch EGR and DOC. Should see about 10% increase in MPG. I could tune it for 200 hp/ 400 ft lbs, but the AX-15 can't handle that so I'm just gonna try and get them to tune for reliability and MPG if it doesn't require increased fuel rail or injector pressure. And I suspect going to 3.73s will give me a slight boost as well, since I can shift into 5th at a more reasonable speed with enough gearing to easily maintain speed under fairly heavy loads. I have a theory that higher gear ratios can actually give peak mpg if used right, because I think one could maintain lower speeds in more ideal RPM windows. Lower speeds equal less load and in my truck I can get mid-20s with road tires and going about 40-55 mph. Speaking of my truck I put similar tires on my truck (KM3s) and the tires dropped my truck down about 20% in MPG, so mud tires certainly have an effect.

 

[Fouledplugs]

The whole 3.07 gears are fine with 33" tires argument is like saying I took out 2 spark plugs and the engine still runs so why would I buy the extra two spark plugs.

I’m stealing this!

 

[BugoutJeep]

Who needs spark plugs?

 

[AndyG]

I’m stealing this!

I know exactly who in Canada you guys are saving this for.

He's probably got a good argument for that too.
" I've been running four plugs for years.... with Justin Bieber cranked up louder than a Who concert...."

 

[RitualHabitual]

Nice to see the bros out tonight. Gimme a break. You still have all that 4.0 power and torque in spite of your ratio, it just changes the driving characteristics. I used to drive a '71 International Harvester pickup with very tall gears--so much so I never used 1st gear even in 2HI unless I was hauling and it would scream its lungs out at 55mph. Monster off-road, just silly on-road unless I had a cord of wood in the bed. I would call it's driving personality 'aggressive' and that was great for a lot of things, but definitely not for daily driving.

A manual TJ with 3.07 gearing sits at the other end of the spectrum--more of a cruiser. Sure, not traditional and obviously not a rock crawler, but still a hell of a lot of fun in certain situations. There's a greater RPM range between gears so while you can't camp out in your peak power range, you do a lot less clutching and shifting and enjoy longer stretches of acceleration between shifts. And believe me there's still plenty of power for accelerating, I just have to adjust my shift points upward in the rpm range a bit, which I kinda like because it makes that Flowmaster sing. It's totally different than a crawler but it's awesome on windy forest service roads in 4LO, on meandering country roads in 2HI, and it's generally more chill to drive. At the same time I can still easily break the tires loose in first gear on dry asphalt and I climb over fallen trees and get plenty of functionality in 4LO. It's just different.

I never said I want or plan to stay at 3.07 on 33-inch tires and I'm not encouraging anyone else to. I'm just biding time while I consider gearing options given the terrain around here, and the enjoyable aspects of the current setup puts me in no rush. It's not like a less-than-ideal ratio renders a TJ useless. I think you're underestimating the I6. Just my 2¢.