- Location
- NC Sandhills
In the past 3.5 years I have been around the forums, the topic of "what Gears for ___tire-size" comes up and gets beat to death pretty regularly. Most answers fit a common theme: Stock for up to 30-31", 4.10-4.56 for 32-35", and over 35" is getting into worryland for the D30, strength and braking-wise. 4.88:1 being the 'lowest' available for a hi-pinion 30. Those swapping in HP44 or 9" etc...have a few deeper ratios to choose from, but disregarding that for now...we're talkin RR30s.
Anyway way back when, I built mine with 4.56:1 for a 4.0l/5speed running 33". Recently swapped those axles into my 4.0l/AW4 XJ (going from 33" and 3.55:1) What a huge improvement! But alas ruined a wheel and tire last weekend, so I swapped back on some 31x9.5 TSLs until I get a set of new shoes.
What I have found is that 4.56 with 31" isn't a purely unliveable combo for my daily use (45 miles of paved twisty/hilly 2-lane) I suppose it would rev a little too much for a highway commuter, but it gets off from stoplights nicely. The one time I 'had' to do a throttle-mash 3>2 downshift to get out of a jam...it responded like a pro-stock car Fuel mileage hasn't been ciphered with the 31" yet, but it seems that it's no better or worse than the 33" were (approx 16-18)
In the long haul, I think 4.10:1 would be 'perfect' for a Jeep that will see 31" for daily use, and probably be OK for 30" as well. My other XJ will see no more than 2-3" lift and 30-31", be used as a daily driver + some towing. It will likely get 4.10s in the diffs at the same time I lift it and install the tires. (keeping in mind that the D30 needs a different carrier for any ratio higher # than 3.55:1, and one might as well do it right the first time)
Summing up my point, low gears and smallish tires aren't the big-bad-wolf some make it out to be...especially if going up a size or 2 later on is in the cards. Of course with low-range engaged, OEM ratios aren't 'terrible' off road, esp. out east where sometimes a little wheel-speed is in order...adding the lower ratio gears just made the experience (both on-road and off) a whole lot better for me.
Anyway way back when, I built mine with 4.56:1 for a 4.0l/5speed running 33". Recently swapped those axles into my 4.0l/AW4 XJ (going from 33" and 3.55:1) What a huge improvement! But alas ruined a wheel and tire last weekend, so I swapped back on some 31x9.5 TSLs until I get a set of new shoes.
What I have found is that 4.56 with 31" isn't a purely unliveable combo for my daily use (45 miles of paved twisty/hilly 2-lane) I suppose it would rev a little too much for a highway commuter, but it gets off from stoplights nicely. The one time I 'had' to do a throttle-mash 3>2 downshift to get out of a jam...it responded like a pro-stock car Fuel mileage hasn't been ciphered with the 31" yet, but it seems that it's no better or worse than the 33" were (approx 16-18)
In the long haul, I think 4.10:1 would be 'perfect' for a Jeep that will see 31" for daily use, and probably be OK for 30" as well. My other XJ will see no more than 2-3" lift and 30-31", be used as a daily driver + some towing. It will likely get 4.10s in the diffs at the same time I lift it and install the tires. (keeping in mind that the D30 needs a different carrier for any ratio higher # than 3.55:1, and one might as well do it right the first time)
Summing up my point, low gears and smallish tires aren't the big-bad-wolf some make it out to be...especially if going up a size or 2 later on is in the cards. Of course with low-range engaged, OEM ratios aren't 'terrible' off road, esp. out east where sometimes a little wheel-speed is in order...adding the lower ratio gears just made the experience (both on-road and off) a whole lot better for me.