guys need your opinions (gear ratios)

bubaloo1983 · Post by **bubaloo1983** » Fri Jun 18, 2004 4:05 pm

k im a little crazy but i want your thoughts...im thinking about getting tires soon and swapping gears....but heres what i want to do i currently have 3.42 gears and i would like to experience i bit better power as well as bigger tires...do you guys think going to 4.56 gears and 31 or 32 inch tires is kinda nuts? or should i just go 4.10s? i need your guys opinions on this cause the shop guys im dealing with arent very helpful...thx

laterz

Post by **HenryJ** » Fri Jun 18, 2004 4:08 pm

4.10's with 31" tires is ideal IMO.
32's are not "doable" without 5" or more lift.

bubaloo1983 · Post by **bubaloo1983** » Fri Jun 18, 2004 4:10 pm

im also thinking about the 5 inch lift though too....so 4.56s are a little crazy if i just go with 31s?

Post by **HenryJ** » Fri Jun 18, 2004 4:14 pm

bubaloo1983 wrote:....so 4.56s are a little crazy if i just go with 31s?

Yes.

bubaloo1983 · Post by **bubaloo1983** » Fri Jun 18, 2004 4:16 pm

how come

Post by **HenryJ** » Fri Jun 18, 2004 4:23 pm

Your rpm's will be too high to comfortably drive at highway speeds.

Mileage will really suck.

The 4.56 ring and pinion for the 7.25" front diff. is not a good choice , IMO.

bubaloo1983 · Post by **bubaloo1983** » Fri Jun 18, 2004 4:26 pm

thx man! ill go with the 4.10s then i hope it will still have more power with the 31s compred to the 3.42 with the stiock tires. thx a bucnh laterz

Post by **HenryJ** » Fri Jun 18, 2004 4:29 pm

It will be really close to the same final ratio as the 3.73's and 29" tires.

I think it is a really good combination.

Be sure to save some money for recalibrating the speedometer, or buying a programmer.

quickbiker · Post by **quickbiker** » Fri Jun 18, 2004 8:01 pm

Here is an excellent chart to go by. Even if the figures don't match, it gives you a reference to go by with gear and tire changes.

http://www.rubicon4x4.com/axle/ratio.htm

a2b · Post by **a2b** » Sat Jun 19, 2004 12:33 am

use 4.56's with 33's to 35's

believe me, i had 31's with 4.10's...it was more than enough gear. i think 32's would be perfect

Post by **HenryJ** » Sat Jun 19, 2004 7:07 am

Here are some dealers that list ratios for the 7.2 IFS-
Randy's ring and pinion - Application chart

West coast differentials - Applications (PDF files)

Brad · Post by **Brad** » Mon Jun 21, 2004 6:12 pm

Where the 4.11s ever available stock in any s-truck? Maybe I could find a front diff with them already in it and just freshen it up. What is the problem with 4.56s?

Brad

Post by **HenryJ** » Mon Jun 21, 2004 6:34 pm

Brad wrote:Were the 4.11s ever available stock in any s-truck?

Yes, my old 1986 S-10 Sport has them, but it has a 7.5" rear. The carriers should interchange though.

Maybe I could find a front diff with them already in it and just freshen it up.

I think the money would be better spent on new parts, unless you have a complete viable unit for a swap.

What is the problem with 4.56s?

IMO, it is just too much gear for the 7.2" axle.
I don't remember exactly what has to be done to use the 4.56 gears in the 7.2 IFS, but there is a special method for installing them that I was not real keen on.
Physically the pinion is pushing the limits for the small housing. I just think with that much gear you'd be more likely to scatter the diff.

I tend to err to the side of caution (bullet-proof) so they may work just fine for most people.

Rusty · Post by **Rusty** » Tue Jun 22, 2004 3:17 am

Physically the pinion is pushing the limits for the small housing. I just think with that much gear you'd be more likely to scatter the diff.

This is also why most people stick to 31" for a max tire size. After I pulled the front diff out of my S10 Blazer and saw just how tiny it is, I could see why. I swear the transaxle in my garden tractor looks beefier.