Topic: Gearing Opinions

[stan98tj]

Here are a few better pics to show you how mine look in relation to the flare. Honestly I always liked the look of 33x12.5s but I bought 33x10.5s because I wanted to help my little 4 popper out as much as I could. Now that I have been running them for a while they have grown on me and I like the look now. I run 34x10.5 Swampers on my xj trail rig but it's a beater and I don't really care about how that one looks.

nice. seems like it has a nice square stance..not too tall and narrow. if i go with 10.5s i may push em out just a hair..but urs looks good. they dont seem too tucked in either. thanks for the pics man.

[buckmaster]

Okay I thought I had this gearing thing figured out.  I have a 98 TJ standard transmission with a 4" lift and 33x12.5 in toyo mt tires.  We use it mostly for hunting and playing around with a little to and from work in the winter but no serious off roading yet.  I live in mountainous BC and it is brutal driving up hills.  From my reading (before I found this site) it seemed like the best bet for me was going from stock 4.10 to 4.56, however after reading here i am thinking maybe 4.88 is the way to do.  I have 4.0 throttle body and spacer on the way to go with new intake but the rest of the engine is stock.  I'm hoping to get 5th gear back and maybe some mpg.  Should I stick with original idea of 4.56 or go up to 4.88.  Also I have Dana 30 front and Dana 35 rears right? Thanks for the help

[Torch_Ind]

Okay I thought I had this gearing thing figured out.  I have a 98 TJ standard transmission with a 4" lift and 33x12.5 in toyo mt tires.  We use it mostly for hunting and playing around with a little to and from work in the winter but no serious off roading yet.  I live in mountainous BC and it is brutal driving up hills.  From my reading (before I found this site) it seemed like the best bet for me was going from stock 4.10 to 4.56, however after reading here i am thinking maybe 4.88 is the way to do.  I have 4.0 throttle body and spacer on the way to go with new intake but the rest of the engine is stock.  I'm hoping to get 5th gear back and maybe some mpg.  Should I stick with original idea of 4.56 or go up to 4.88.  Also I have Dana 30 front and Dana 35 rears right? Thanks for the help

if your 4banger stock you will already have 4.11's

go strait to 4.88's you will even want bigger but requires axle changes to get any bigger gear then that!! if you do a lot of hills you won't regret it!!!!

[FourbangerYJ]

What ^^^ said, do the 4.88's.  Welcome to the board 

[stan98tj]

What ^^^ said, do the 4.88's.  Welcome to the board 

recently ive begun leaning towards 4.56. given my 3spd auto-no overdrive etc, some of the 4x4 shops i checked with recomended 4.56. ill have to really look this over right before i lay the $$ to do it.

[FourbangerYJ]

recently ive begun leaning towards 4.56. given my 3spd auto-no overdrive etc, some of the 4x4 shops i checked with recomended 4.56. ill have to really look this over right before i lay the $$ to do it.

From what I understand 4.56's with the 3 speed auto is a good choice.

With Buckmaster, he has the 5 speed stick and 33's so the 4.88's are the right choice for him.

[jfrabat]

With a stick, I would go to 5.13 if I could (I currently run 33's and 4.88, but before, I ran 31's and 4.88 and it was SWEET!  I wish I could get that back without having to drop in 2 new axles!).

[Bounty Hunter]

From what I understand 4.56's with the 3 speed auto is a good choice.

With Buckmaster, he has the 5 speed stick and 33's so the 4.88's are the right choice for him.

Going with 4.88 will only raise your RPM's by 200 over stock tires and stock gearing, and it's best to go slightly lower on gearing when dropping that kind of coin.  It also helps compensate for the large increase in rotating mass, as regearing to 4.56 would only help compensate for the increased tire diameter.  You will be able to get the heavier tires moving much easier with 4.88 gears.

For 33" tires beneath a 4banger, you should regear to 4.88 if an auto and (ideally) 5.13 if a 5spd.  Unfortunately 4.88 is as deep as the stock axles allow.

[mrcabinet]

I have 33x12.50 ATs, 62mm tb, cai, flowmaster exhaust, 2.5l 5 spd. with 4.56 gears. I wish I had 4.88's, and that's here in the desert where it is pretty flat. If you drive any hills at all, go 4.88. 4.56 with the 3 spd. auto would be perfect.

[stan98tj]

Going with 4.88 will only raise your RPM's by 200 over stock tires and stock gearing, and it's best to go slightly lower on gearing when dropping that kind of coin.  It also helps compensate for the large increase in rotating mass, as regearing to 4.56 would only help compensate for the increased tire diameter.  You will be able to get the heavier tires moving much easier with 4.88 gears.

For 33" tires beneath a 4banger, you should regear to 4.88 if an auto and (ideally) 5.13 if a 5spd.  Unfortunately 4.88 is as deep as the stock axles allow.

well now i thought i had it figured out and now ya put me right back at square 1. given that i dont know much (about gearing) and i can only go by ideas given to me by others with more experience im really gonna have to consider all options. this really has to be perfect. Im planning on going with 33x10.5s..they will be lighter then the 12.5s. Im not sure if that would factor in much. I DONT want to end up with a jeep that is sucking down more gas then what it already does, I DONT want a jeep that cant go over 60mph and if it does its screaming at over 3k..and i DONT want it to be slower then it already is.  Many of the charts i looked at suggested somewhere in the 4.20 range-so i figured 4.56 would work cause it was closer then 4.88. the question remains i guess: 4.56 or 4.88 for my 3spd auto?

[Bounty Hunter]

Take a looky at this chart.  Compare 3.73 gears and 27" tires, you get 3017 RPM.  Slide on down to 33" tires and run across horizontally until you find a similar RPM.  4.56 gears had you at 4.56 gears.  IMO, and many will tell you the same, you need to go a smidgin deeper in gears than what puts you back at stock RPM, in order to account for the added mass of the larger tires AND to make the time and expense more worthwhile.  4.88 gears is ONLY 212 RPM higher than with 4.56, something you can definitely live with on the highway.  I'd be willing to bet your mileage would be better with 4.88 as the engine won't be lugging as much off the line and at speed.  The 4banger likes the revs.

[stan98tj]

Take a looky at this chart.  Compare 3.73 gears and 27" tires, you get 3017 RPM.  Slide on down to 33" tires and run across horizontally until you find a similar RPM.  4.56 gears had you at 4.56 gears.  IMO, and many will tell you the same, you need to go a smidgin deeper in gears than what puts you back at stock RPM, in order to account for the added mass of the larger tires AND to make the time and expense more worthwhile.  4.88 gears is ONLY 212 RPM higher than with 4.56, something you can definitely live with on the highway.  I'd be willing to bet your mileage would be better with 4.88 as the engine won't be lugging as much off the line and at speed.  The 4banger likes the revs.

so that means with 4.88s ill be screamin at 3200rpms at 65mph. boy thats gonna be loud lol. by the way, why did you choose 27" tires. arent 29" the stock size? perhaps i should pose the question as follows...this is still going to be my daily driver which will include highway driving will the 4.88s be too much?

[Jeffy]

Keep in mind these charts are set up for 1:1 ratio (as all vehicles have 1:1) and does not account for OD which is a 'cruising gear'.

[stan98tj]

Keep in mind these charts are set up for 1:1 ratio (as all vehicles have 1:1) and does not account for OD which is a 'cruising gear'.

but i dont have an OD. honestly the problem im running into is most ppl have a 5spd and the option is 4.88s for 33s. i searched online and found a few 2.5 autos with 4.88s (some were running 35s though) but i dont know if they are daily driving their rigs. It seems like every time i settle on a ratio someone brings up a opinion which has me doubting mine...and i def appreciate all the input. Jeffy, do you think 4.56 would be good for a DD jeep. i wheel whenever i can so id like to get some power out of this upgrade..

[jfrabat]

but i dont have an OD. honestly the problem im running into is most ppl have a 5spd and the option is 4.88s for 33s. i searched online and found a few 2.5 autos with 4.88s (some were running 35s though) but i dont know if they are daily driving their rigs. It seems like every time i settle on a ratio someone brings up a opinion which has me doubting mine...and i def appreciate all the input. Jeffy, do you think 4.56 would be good for a DD jeep. i wheel whenever i can so id like to get some power out of this upgrade..

I drove my 5-speed with 31's and 4.88 and I was one happy camper (it was a dd at the time).  Should be similar to your auto, 4.88's and 33's...