can't decide on gears for 33's DD 5spd

[epoxy_nc]

i must have read 1000 posts about gears by now, but 95% of them were for auto.

i have an ax15, d30/chrys 8.25, 33x12.5, everything stock (except for lift and sye)

(my tires are 32.8 in, high)

i've been trying to decide on 4.10 or 4.56 for the past week and can't seem to hit the buy button on either.

i like the appeal of 4.56's, but i drive a lot every day (school, work, g/f) and usually amounts to around 300 miles a week... 80% of it at 55mph. i know that it wont rev too much there, but what if i go on a trip? i usually go on long trips about once a month (6hr - 12 hrs) and don't know how bad 4.56's will hurt me there.

i was thinking just go with 4.10's since i only go off road mainly on the weekends, and minimal on the weekdays.... but i'm so torn help me decide!

and remember... this is a 5spd

 

[shimmy]

def go with 4.56, you'll love the power with a 5spd

 

[RyanM]

4.10's are ideal for what your going for. But if you plan on going to 35's in the futrue i would definately go 4.56's. i have a 5 spd and 36's and 4.88's i think its a good balance, but would love to have 5.38's or a something lower than the shitty 2:72:1, in some situations

 

[epoxy_nc]

i don't doubt that... just dont know if i want to rev the crap out of my engine on long ass 80mph trips

don't feel like paying for the gas

 

[EricT]

i have 35's and 4.56, had 33's and I loved it

 

[RyanM]

on a AX-15? im hitting close to 3000k at 80 on long trips.

 

[rocklandxjer]

^ which even though it sounds high...
really isn't the jeep 4.0 loves to run 2500-3000. your gas milage may even improve, and your pickup will definately improve, meaning less gas needed to accel..

damn, thats twice now ive agreed with you....

 

[dj's 2000 xj]

^ which even though it sounds high...
really isn't the jeep 4.0 loves to run 2500-3000. your gas milage may even improve, and your pickup will definately improve, meaning less gas needed to accel..

damn, thats twice now ive agreed with you....

I left my stock gearing @ 3.55 and now have 32" mt/r and I rev higher 24-2600 down the road and get pretty fair mileage, like when stock. What a mystery these xj's are, everyday a new page. Today, while traveling 30 mph, I stomped the skinny pedal, when it kicked down I scratched my tires! I was very excited, slick black top, hard rubber goodyear mt/r what a blast!!! O yeah, suggest 4.10 because you have 5 speed.

 

[ChiXJeff]

I've ran both 4.10s and 4.56s with 33x12.50 MT/Rs and an AX15 5spd. In no way are 4.10s superior to 4.56s. With 4.10 gears, the 4.0l struggles with any kind of a load.

 

[ColoCherokees]

My specs - '96, 4.0, D30/D44, 4.56s, 161,XXX mi, AX-15/231, 33x9.50 BFG ATs, at 5500-6000 ft altitude for DD, 5500 to ~12000 ft altitude wheeling.

Performance on trail (rock-crawling, steep grades here in CO) is great - accel from stoplight is great. Yes, engine RPMs on pavement are generally equal to, or above 2000 rpm, but I'm still getting 15-18 mpg mixed HWY/CITY(conservative driver when on pavement). Above 55 or 60 mph, engine noise is not appreciatively louder than the stock arrangement (my Magnaflow muffler is, however).

The 33s weigh more, so besides the math of their larger diameter to return to a stock ratio, you'll appreciate some more gearing to offset their greater weight.

In short, go with the 4.56s. If you're going to all the bother to lift/modify your XJ to fit 33s for off-road performace, why worry if you need to turn the stereo up a notch or two to compsensate for the higher engine RPMs on the occasional trip home at 75mph?

 

[sidriptide]

^ which even though it sounds high...
really isn't the jeep 4.0 loves to run 2500-3000. your gas milage may even improve, and your pickup will definately improve, meaning less gas needed to accel..

damn, thats twice now ive agreed with you....

X2...

your fuel economy will not suffer just because you add deeper gears. as pointed out, the 4.0L likes to rev a bit and breathe. my rig, AX-15/4.56/33s gets a consistant 16 mpg around town and highway gets 18-19 mpg.. i run it on the highway about 70 - 75 mph and thats about 2800 rpm or so.. plenty of power and not over-revving..
to put it into perspective i drove it to Moab from Ma last may and aside from stopping for gas or switching highways i NEVER shifted out of 5th gear for a single hill until i got past denver. plenty of power in that RPM range.

i know alot of people "live" with 4.10s and it seems people are afraid of running higher RPM on the highway and killing their mileage but thats really not the case with a properly running engine.

what WILL kill your mileage is a heavy foot around town. hard aceleration dumps alot more fuel than consistant throttle position at highway speeds.

 

[Trailbst]

I agree with Sid.

I know from personal experience that I did NOT like my 34s with 4.10s and a 5spd.

Go to one of the gearing calculators. Put in the numbers, and like Sid said, look for gearing that will put you between 2500-3000 RPM at your cruise speed. Should be 4.56s and you'll love it.

 

[DaveW]

Im regearing now to run 4.56 and 33" with a 5-speed.

I've gone the route of trying to keep stock ratio for a daily driver and it worked OK. That was 3.73 and 31". I have to down shift on any decent hill now. As the motor ages it will slowly loos a little pep. You will notice that over time. Think about where you will be in a few years.

When you check the charts and calculate ratios the tire mass is not included. The problem is that you add mass to the tires. A 33" is about double the mass of a stock 205/75-15. The stock gearing is rather tall to get you good gas milage spinning little tires.

I've had many people tell me the when it gets to the output shaft of the tranny/t-case it is the same, or at least very close, for both auto or stick. It is just that you can compensate for tall gears better with a stick. The autos conpensate for you, so you don't notice the struggles and down shifts at lower rpms.


.....
Why hasn't Remi pop in here. He likes 33" with 4.88 and a 5-speed.

 

[RyanM]

get the 4.56's and be done with it. you'll love it. i can't wait to drop in my hp44 so i can run 5.13's with some new 37 meats.

 

[epoxy_nc]

k thanks to all who contributed...i'm going with 4.56! thanks!

 

[Big Red]

get the 4.56's and be done with it. you'll love it. i can't wait to drop in my hp44 so i can run 5.13's with some new 37 meats.

Go with 5.38 gears in your HP44, you will love it, I sure do.

For you with the 33's and stock axles, get the 4.56 gears or even 4.88s if you have a dana 35 or dana 44. Don't spend the $ to gear your Jeep and then find you want more, no better way to waste $ than doing things twice in a short period of time. When things break you fix them, when you upgrade, do it once.
If you insist on 4.10s, get axles out of a 2.5L 4 banger 5 speed, those had 4.10 gears and you can install axles a lot easier in your garage, then trying to set up gears (not for the faint of heart, takes skill and experience). Axles just bolt in, plus you'd have spares.

 

[RyanM]

Go with 5.38 gears in your HP44, you will love it, I sure do.

i haven't done much research on gear sets for that axle. i thought the limit was 5.13's for the hp44fronts. i know i can go 5.89 in the rear...

 

[bigwillxj]

Ill have 4.56's/ax15/32's next week so ill let you know how a picky teenager likes it.

 

[Big Red]

i haven't done much research on gear sets for that axle. i thought the limit was 5.13's for the hp44fronts. i know i can go 5.89 in the rear...

5.38s are the limit for the HP44 and HP60 and is low enough really even if you had regular/standard low pinion dana 44's. Any lower than that and you are losing way too much contact between the ring and pinion (teeth contact).

 

[Big Red]

Ill have 4.56's/ax15/32's next week so ill let you know how a picky teenager likes it.

You should have fun with the power and how fast you get up to speed, your highway cruising will be up there a little bit on 32's, but you should be fine. I had 4.88 gears on 33" TSL radials with a 4.3L 95' Chevy Vortec and 4L60E auto tranny and loved the power. You also have enough gear for 35's if they are in your future, at least on the road, off road you might want to go with lower t-case gearing as well as your axle gearing, have fun. :wave:

Troy