Tires and gears

[Dale]

The Goodyear mt's are almost gone and it's time for new ones! I am going to put larger tires on 37-38 inch and need to get a lower gear ratio. I was thinking 4:88? If anybody has any advice or suggestions on tires or gears I would appreciate it. I like having the ability to drive her on the road as well!

[Lurch]

4.88's and 37"s work great on my bronco. The speedo is even acurate within 3 mph. With the overdrive in your heep it should work great.

[OldGreen]

Are you going to lift it some more or highline it?

[iaccocca]

[Lud]

I would go 4.88's with that tire size.

[OldGreen]

I'd actually probably do 5.13s. I had 5.38s with 35s. It was lovely on the trail, but just a skosh too low on the road even with a 5 speed.

[White trash]

I'm not that familiar with the rig so I have to ask what axles are under it? I'll assume its a ruby so its got Dana forty faux's. Since OG is suggesting ratios lower that what is available for the 30.

Didn't I see somewhere that its an auto too? If so it doesn't HAVE to have such low gears like a stick does but a nice balance in the 4.88 area would be best to keep the trans happy and still move down the road decently.

[OldGreen]

I'm not that familiar with the rig so I have to ask what axles are under it? I'll assume its a ruby so its got Dana forty faux's. Since OG is suggesting ratios lower that what is available for the 30.

Didn't I see somewhere that its an auto too? If so it doesn't HAVE to have such low gears like a stick does but a nice balance in the 4.88 area would be best to keep the trans happy and still move down the road decently.

Good point on the auto. . .hadn't thought about that. Wife's WJ on 32" tires with 3.73s is a crawlin' machine.

Considering the torque curve of the 4.0 and the size difference between stock and new tires a gear ratio that is 20% lower than stock (4.9 ~ 4.88) would keep the rig in the same powerband as stock. The additional rolling resistance and leverage (from an engine standpoint) are pretty negligible with a 4.0 since it has really good torque anyway. I do think that I'd be inclined to throw a bung in for a tranny temp gauge if you intend on taking it on any extended road trips. Those big tires are kind of like towing a trailer as far as the tranny is concerned.

Still. . .what about clearing the bigger tires? A TJ with a 5" lift will clear 37s if it is done correctly, but I've sure seen a ton of them done wrong.

[Dale]

THANKS FOR ALL THE ADVICE, IT ALL SOUNDS REALLY GOOD. I DO HAVE THE 5 SPEED WITH THE DANA 44'S 4:11 GEARS AND 4: 1 TRANSFERCASE. iT IS PLENTY LOW BUT WITH 35 RIGHT NOW I AM LOSING A LOT OF POWER ON THE ROAD. I AM HOPING 4:88 WILL MAKE UP FOR THE DIFFERENCE FOR THE 37-38 SIZE TIRES. FAR AS LIFT IT HAS A 4 INCH LIFT ON IT AND FOR THE EXTRA CLEARENCE NEEDED I WAS GOING TO DO SOME BODY CUTTING AND POSSIBLY SOME SPACERS FOR THE WHEELS THE 35 RIGHT NOW HAVE PLENTY OF ROOM.I SAW SOME GUYS JUST MOVE THERE WHOLE FENDERS UP. I AM ALL ABOUT THE LEST AMOUNT OF LIFT POSSIBLE WITH THE MOST GROUND CLEARENCE POSSIBLE.

[White trash]

It's not low until you trim the hood and top...

[79chevy39.5's]

yeah you can do the homemade high lines and i think they look good

[OldGreen]

It's not low until you trim the hood and top...

and drop the body. . .

Do it.

[White trash]

It's not low until you trim the hood and top...

and drop the body. . .

Do it.

Yup, swap the body bushings for pieces of mudflap and cut the floor a bit to tuck everything up nice and tight. I have never understood why it's not more common to trim the floor and go nice and flat the easy way on a Jeep. It's not like there isn't 6" under the seats or something...