question's about re-gearing
- Thread starter hrjaw
- Start date
SunDvl
New member
IMO, I think an 8.8 would be overkill for what your looking to do, both in terms of money and offroad performance. You would be much better off buying used TJ axles with factory 3.73's, as they can usually be had extremely cheap and will bolt right in. The price of used TJ axles would be cheaper than buying new gears and having them installed by at least $400.
Fergie
Expedition Leader
SunDvl said:
I agree as well.
The 8.8 is a boat anchor. You will lose about an inch of clearance beneath the pumpkin.
If you can find them, get a set of 3.73 axles from a TJ, if not those, then 3.55s from a TJ.
If you need to go to deeper gearing, that is when you get in to new axles and regearing costs.
Assuming that your Jeep came originally with P235's running around 29 inches, and that you now run 31's, the difference in diameter of the tires of choice is 1.069. That is, the larger tires are bigger by that factor. Changing gears in order to simulate stock performance requires changing gears at or near the same factor of change. 3.07 x 1.069 = 3.28. Don't know if there are any gears in that range, but there likely are in 3.54 or 3.73, or thereabouts. With either gear set and an auto trans, you should be able to run anything from 31 to 33 without issues, and without overheating the transmission.
Even if you originally had 27 inch tires, the difference between those and 31's, factored into a gear ratio, would still result in 3.525, which is very close to 3.54. So, if you want to stay close to stock driving parameters with the larger tires, 3.54 should be all the change you need. 4.10's would cause you to run farther up in the rpm range and likely use a noticeable amount more in fuel. Off road, 4.10's would be an advantage with the larger tires, but not much of one. IMHO, 4.10 gears in a stock or near stock Jeep with no more than 33 inch tires is only needed if you have the 4 cylinder, and then only to make up for the lack of power on tap. The 4.0 six cylinder and an auto trans will pull the larger tires just fine with the intermediate gears in the 3.5 to 3.7 range.
Even if you originally had 27 inch tires, the difference between those and 31's, factored into a gear ratio, would still result in 3.525, which is very close to 3.54. So, if you want to stay close to stock driving parameters with the larger tires, 3.54 should be all the change you need. 4.10's would cause you to run farther up in the rpm range and likely use a noticeable amount more in fuel. Off road, 4.10's would be an advantage with the larger tires, but not much of one. IMHO, 4.10 gears in a stock or near stock Jeep with no more than 33 inch tires is only needed if you have the 4 cylinder, and then only to make up for the lack of power on tap. The 4.0 six cylinder and an auto trans will pull the larger tires just fine with the intermediate gears in the 3.5 to 3.7 range.
computeruser
Explorer
You want 3.73 gears for 31" tires. Best all-around combination with the 3-speed auto.