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-   -   gear ratio?????? (http://www.wranglerforum.com/f210/gear-ratio-62119.html)

tma300 09-17-2010 08:44 PM

gear ratio??????
 
If I change my gear ratio - stock right now - can I get more power in 4th and 5th gears? If I can what ratio should I change it to? I have a 4 cyl.

4Jeepn 09-17-2010 08:53 PM

Well few things to consider, what tire size are you running? You should have 4.11's right now stock.. You would need to jump to 4.88's to see a big difference. However at the dana 30 pinion gets very small past 4.11. Also are you planing to upgrade the dana 35 at all?

tma300 09-17-2010 09:00 PM

I have 31/10.5/15 kumho tires. Would I need a piston upgrade too?

530ktm 09-17-2010 09:37 PM

Quote:

Originally Posted by tma300 (Post 776959)
I have 31/10.5/15 kumho tires. Would I need a piston upgrade too?

Keep it like it is with the 4 cylinder. How is a piston upgrade going to help with anything here is my question??:confused::confused:

Jerry Bransford 09-18-2010 09:27 AM

Quote:

Originally Posted by tma300 (Post 776959)
I have 31/10.5/15 kumho tires. Would I need a piston upgrade too?

Don't worry about the pistons, they don't need an upgrade for anything reasonable you'd ever do to your Jeep. So far as regearing goes, don't bother for only 31" tires. It's when you get to 33" tires that it becomes reasonable, cost-wise (about $1200), to regear to 4.88.

Your engine just doesn't put out a lot of power so if it's not enough with even 31" tires, you're just going to have to live with it or trade it in for a Jeep that has the larger 4.0L engine. Regearing it with only 31" tires would not be the thing to do, you would then have excessively high engine rpms. That's why I said that regearing only becomes a reasonable/good thing to do once you get to the 33" tire size. :)

Jerry Bransford 09-18-2010 09:35 AM

Quote:

Originally Posted by 4Jeepn (Post 776950)
However at the dana 30 pinion gets very small past 4.11.

4.88 in a Dana 30 has a good reputation, it doesn't have a problem at all. Plenty of hardcore wheelers run it with a locker and 35" tires without issue at all, and I've done had that ratio in two Jeeps. Everyone worried about 4.88 when it first came out in the late nineties for the Dana 30 but the fears proved to be unfounded. :)

Gate53 09-18-2010 10:00 AM

Jerry it seems to me that in a drive train you are always going to have a weak point and that the Dana 30 is really great enginering. With it, it seems that the weak point is the axel shaft with the larger tires. That being said I would always rather spend an hour swapping out an axel and go right back to wheeling than tear out a pinion or ring gear and trailer it home. I bought a full set of shafts and replaced the u-joints and have them ready to go in. I run 32's on a 2000 4 popper and I get to spend my time wheelin instead of wrenchin.

Jerry Bransford 09-18-2010 10:11 AM

Quote:

Originally Posted by Gate53 (Post 777379)
Jerry it seems to me that in a drive train you are always going to have a weak point and that the Dana 30 is really great enginering. With it, it seems that the weak point is the axel shaft with the larger tires.

Absolutely, you are dead-on. Like when I did break things on my 4.88 and locker equipped Dana 30 running 35" tires, it was the axle shaft and u-joints. The 4.88 gears themselves never gave any problems. :)


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