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Which gearing for 33s with best MPG

P

pfcstone777

NAXJA Forum User
Location
New Jersey
I want to get 33s very soon because my 31s are wearing out and wanted to know what gearing (4.10 or 4.56) will give me the best MPG with 33s?

Thanks
 
Last edited:
Not this again....

Details, man, DETAILS!!!!! What year, what engine, what transmission, anything about the drivetrain.

BTW, you might also want to look up at the stickies in this forum.
 
Do you do more city driving or more highway driving?

A lower gear (such as 4.56) should increase city mpg but decrease highway mpg. Whereas a 4.11 would probably give you a bit less city mpg but a bit more highway mpg.

I'd say 4.56's for 33's though....or 4.88's......which is the lowest you can go...4.11's seem to be good for up to 31's as they were used stock with the stock tire size. Not that I have anything to talk about though, I have 3.55's with 33's. I'd love to find a set of junkyard axles with 4.11's! The only 4.11's I've seen in a junkyard are paired with a Dana35.......I have the 8.25 and wouldn't want to downgrade for the sake of lower gears.
 
I'm running 4:56's on 33's with the AW4, but I am considering going to 4:88's. I'm at a much higher altitude than you though (Utah) which will affect my numbers differently than yours. I usually average 16-17 hwy and 13-14 city mileage approximately. At your altitude, you should be fine with the 4:56's.
 
Deeper is better.

While it may not make sense, gearing a little lower will often give you bettere economy too - the engine won't have to work as hard to spin big meats.
 
i like my 4.56 for a mostly DD... i dont think i want any deeper. but i would also not go any less.
 
I'd say if you can pull 17ish+ mpg hwy with 4.56's then go for that.
 
veedubshafer said:
I am so glad for this thread. Finally! A topic that has never been covered!
Click to expand...

HAHA! really! But seriously, I am running 4.10's with my 33's. Honestly, I love it. I drive alot of back roads with no lights at almost highway speeds, and Its great. No downshifting on inclines and around town, I really like it. Now I can't say that I wouldn't go to 4:56's but im gonna stay with 4.10's untill I need 4.88's.

Put it this way. If you can get a REALLY good deal like I did on some 4.10's versus buying everything for 4.56's, I would go 4.10's unless you just want the lower gearing.
 
Cherokeekid88 said:
HAHA! really! But seriously, I am running 4.10's with my 33's. Honestly, I love it. I drive alot of back roads with no lights at almost highway speeds, and Its great. No downshifting on inclines and around town, I really like it. Now I can't say that I wouldn't go to 4:56's but im gonna stay with 4.10's untill I need 4.88's.

Put it this way. If you can get a REALLY good deal like I did on some 4.10's versus buying everything for 4.56's, I would go 4.10's unless you just want the lower gearing.
Click to expand...
You'll say you're happy until you run with deeper gears. I ran for a year with 33s, 4.10s and a 5spd until I destroyed a pinion bearing set (unrelated to the gears.) I knew already that 4.10s were marginal, and the difference 4.56 gears made was pretty significant.

It'd have to be almost a flat out steal for me to consider 4.10 gears with 33s again, regardless of transmission.
 
I have 32x11.5 at's and 4.56 gears. I thought I would use for the street and long distance traveling. I also have 33's for off road. The 32's push my R.P.M.s into the drone exhaust zone at highway speeds and probably cost M.P.G. I'm selling the 32's.
:D
 
From my speedo page.

Gearing for best MPG​
Most people think that less revs will equal better MPG. That is not always the case as less revs can also mean more strain on the engine which causes more fuel use. According to a engine design text‚ maximum fuel economy occurs with open throttle and at a piston speed of 1200 – 1500 ft/min. So if you know the stroke of your engine‚ you can calculate the rpm for best fuel economy. Usually comes out somewhere between 2000 – 3000 rpm. Dino provided me with the following numbers. The 4.0L has a stroke of 3.411" and a 4.5-4.8L stroker has a stroke of 3.895" so the numbers would be as follows: 1200-1500ft/min piston speed = 2110-2640rpm on a 4.0, 1848-2310rpm on a stroker. So use the table above to pick the right gears for your tyre size. Above gives the average cruising speed of 65 mph or 105 kph. The more weight you carry the more revs you need to stop the extra fuel use through engine strain. The extra revs is also better for the auto and even engine temperature with less strain and the water pump running faster to circulate the coolant.
You can also use the gear chart to work out what axle ratio is needed to return you to stock gearing by finding your stock gear tooth number under the new tyre size. Below is also a guide to what revs you will have with different combinations. This is about what you will have in overdrive or forth in a auto, ( 0.75 ). Pre '91 will be slightly slower at 0.70, Peugeot ( BA-5/10 ) had a 0.72 and faster for a AX-15 manual at 0.79 or a AX-5 with 0.85.​
RPM's at 65 MPH/105 KPH w/ 3.55:1 axle gears running 28's: 2,076 RPM
RPM's at 65 MPH/105 KPH w/ 3.55:1 axle gears running 30's: 1,938 RPM
RPM's at 65 MPH/105 KPH w/ 3.55:1 axle gears running 31's: 1,876 RPM
RPM's at 65 MPH/105 KPH w/ 3.55:1 axle gears running 32's: 1,817 RPM
RPM's at 65 MPH/105 KPH w/ 3.55:1 axle gears running 33's: 1,762 RPM
RPM's at 65 MPH/105 KPH w/ 3.55:1 axle gears running 35's: 1,661 RPM

RPM's at 65 MPH/105 KPH w/ 4.10:1 axle gears running 28's: 2,398 RPM
RPM's at 65 MPH/105 KPH w/ 4.10:1 axle gears running 30's: 2,238 RPM
RPM's at 65 MPH/105 KPH w/ 4.10:1 axle gears running 31's: 2,166 RPM
RPM's at 65 MPH/105 KPH w/ 4.10:1 axle gears running 32's: 2,099 RPM
RPM's at 65 MPH/105 KPH w/ 4.10:1 axle gears running 33's: 2,035 RPM
RPM's at 65 MPH/105 KPH w/ 4.10:1 axle gears running 35's: 1,919 RPM

RPM's at 65 MPH/105 KPH w/ 4.56:1 axle gears running 28's: 2,668 RPM
RPM's at 65 MPH/105 KPH w/ 4.56:1 axle gears running 30's: 2,490 RPM
RPM's at 65 MPH/105 KPH w/ 4.56:1 axle gears running 31's: 2,409 RPM
RPM's at 65 MPH/105 KPH w/ 4.56:1 axle gears running 32's: 2,334 RPM
RPM's at 65 MPH/105 KPH w/ 4.56:1 axle gears running 33's: 2,263 RPM
RPM's at 65 MPH/105 KPH w/ 4.56:1 axle gears running 35's: 2,134 RPM

RPM's at 65 MPH/105 KPH w/ 4.88:1 axle gears running 28's: 2,855 RPM
RPM's at 65 MPH/105 KPH w/ 4.88:1 axle gears running 30's: 2,664 RPM
RPM's at 65 MPH/105 KPH w/ 4.88:1 axle gears running 31's: 2,579 RPM
RPM's at 65 MPH/105 KPH w/ 4.88:1 axle gears running 32's: 2,498 RPM
RPM's at 65 MPH/105 KPH w/ 4.88:1 axle gears running 33's: 2,422 RPM
RPM's at 65 MPH/105 KPH w/ 4.88:1 axle gears running 35's: 2,284 RPM​
 
If everyone would read the above post (and the rest of go jeeps website) these questions should be non-existent. In a perfect world of course.

Good info, thanks for sharing (again)

~James
 
So, my 4.88s I'll be running soon should be perfect for the 4.0 and 33s, then eventually by the time I build my stroker (eventually) I'll probably be on 35s already and that will drop it right back into the proper range for economy. Should be sweet for wheeling either way. :D
 
Blaine B. said:
Do you do more city driving or more highway driving?

A lower gear (such as 4.56) should increase city mpg but decrease highway mpg. Whereas a 4.11 would probably give you a bit less city mpg but a bit more highway mpg.

I'd say 4.56's for 33's though....or 4.88's......which is the lowest you can go...4.11's seem to be good for up to 31's as they were used stock with the stock tire size. Not that I have anything to talk about though, I have 3.55's with 33's. I'd love to find a set of junkyard axles with 4.11's! The only 4.11's I've seen in a junkyard are paired with a Dana35.......I have the 8.25 and wouldn't want to downgrade for the sake of lower gears.
Click to expand...


before you gear that front end i would suggest grabbing a HP30 for cheap and using that
 
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