Is this a good setup, 33" tires with 4.11 gears?

[88GW]

I want to know if anyone is running 33 inch tires with 4:11 gears or ratios close to that. If you are how does it perform and what kind of RPMS are you turning at highway speeds? I am thinking about adding 33's and would like to know from someones personal experience. The online gear calculators say between 3.90 to 4.11 or so.

[Iron Horse]

From what I've read around here, 3.73's are kinda what's recommended for 33's and 4.09's for 35's. Although it depends on what type of driving you will be doing. Mostly on-road go with the 3.73's; 50/50 or more offroad I'd say 4.09's and up.

[Iron Horse]

Hey....I just became a Grease Monkey. Heh,heh now I have an excuse for the dirty finger-nails. :D

Andy

[newbie]

Here's a simple formula that should address your concerns.

Speed (MPH)x Final Drive Ratio x 336/Tire size (in inches) = RPMs

Final drive ratio= transmission gear ratio (1.0 for high gear in the TH400/TF727/ and most manual trannies without overdrive) x Ring and Pinion gear ratio (4.11 in your case) x Transfer case gear (1.0 in high-range)

So with 4.11 gears and 33" tires crusing at 65 MPH you can expect to turn about 2,720 RPMs.

(65x4.11x336/33=2720.072)

It's also fun to factor in the transfer case low-range. For example a 4.11 geared front and rear gearset with a 2.62 Transfer case low-range and a 2.45 1st gear would give you a crawl ratio of 26.0004 then plug that back into the formula to get:

Speed(10mph)xFinal Drive Ratio(26.0004)x336/33=2686.18 RPMs

Or if you are looking for a specific speed at a given RPM then use this formula:

RPM x Tire Size/Final Drive Ratio x 336=MPH

Or if you wanted to find out what gear ratio you should use to get a specific RPM range at a given MPH speed you would use:

RPM x Tire Size/MPH x 336

So if you only wanted to turn 2500 RPMs at 65 MPH with 33" tires you would plug it in like this:

2500 x 33/65 x 336=3.777

So if you wanted 2,500 RPMs at 65MPH you'd need a 3.777 equivalent gearset for the rear end.

Let's plug in 3.73 just to see how close that would get us.

65 (MPH) x 3.73 (Gear Ratio) x 336/33=2,468 RPMs, so we'd be pretty dang close.

Hope this helps!

[ October 15, 2001: Message edited by: newbie ]

[64Trvlr]

Unless you spend all your time on the freeway I'd use 4:11's with 33's and 4:56's with 35's. I'm running 4:88's with 33's and love it, but I spend most of my time off road.
:cool:

[River Beast]

I agree with 64Traveler...4.11's are GREAT for 33's

I ruyn 4.89's with 39.5's and love it. Can't wait to go down to the 38's and see the difference...

[88GW]

Thanks guys I think I am going to go with 4.11's. I want to have a little more off the line power for city driving throttle jockeys. I do have a 12 mile commute to work with about 7 of those mile on 55 mph highways, so I am not too concerned. Anyone running this combination????????????????

[RustyJeep]

I will be as soon as I swap the tires over. :D I'll let you know then.

[WillyPete]

how bout 4.88s and 35s? 3k at 65 mph :eek: :eek:

i need a 700r so bad...

[trickc]

I've got 33's on buttercup with 4.10 gears, Its mostly a street truck and is ok around town and limited highway use. Ive also run 3.73's with 33'and an auto and was happy with it also. But the 4.10's should make you pretty happy, if its too much then its just a reason to go with bigger tires! :D