Topic: 33 Tires Gears and Gas Mileage

[Wes W.]

The Gearhead on Gears and Gas Mileage goes like this Equivalent Ratio= new Tire Diameter over Old Tire Diameter x Original Gear Ratio. Example 35 over 28 x 3.55 =4.4375,Matching that up to the closests available ratio equals 4.56:1 . We can make this easy by following  a few rules of thumb; Rigs with 31-inch tires should have 3.73 gears . Rigs with 33 inch tires should 4.10s,  35s=4.56s 37s and 38s need 4.88s.SO using Effective Ratio Old Tire Diameter over New Tire x Original Ratio ex, 28 over 35 x 3.55 = 2.84 The effective Ratio tells you the overall ratio of new tire and gear combo and is the equivalent  of ratio formula.PS you need 4.10 gears with 33 tires.

[Mozman68]

Not sure why you are telling us this....did someone ask this question??

The correct info is already listed in the FAQ section....I say CORRECT because there is no way 4.10 gearing is correct for 33's.  My Jeep came stock with 4.10 gearing and 27's.

4.88 to 5.13 would be better for 33's (I'm guessing that without even looking at the FAQ)

[dexetr30]

Nice formula

I'll have to keep this in mind when I gedt around to doing the TJ.

My YJ has 4.10's with 33's so I guess I'm good on that end.

If this formula is correct (and it seems like it is) it should be made into a sticky or put into the "The Facts and nothing but the FAQ" section.

[Jeffy]

Gear ratio numbers are wrong but the formula is correct.

4.10's and 33's are nowhere near optimal, like Mozman said.

There is already a gear chart in the FAQ.  I will consider adding the formula BUT no one really uses them.  They always want just the chart or a java calculator.

This post is a bit random.

[dexetr30]

Hmmm, my 4.10's feel just fine in my yj. Maybe off road it will be a bit different. I haven't gotten to wheel with it yet so who knows.

I do agree though... this post is a bit out there and random.

[Jeffy]

Hmmm, my 4.10's feel just fine in my yj. Maybe off road it will be a bit different. I haven't gotten to wheel with it yet so who knows.

I do agree though... this post is a bit out there and random.

Wait till you change gears to 4.56, 4.88's or even 5.13's and you'll wonder why you didn't do it sooner.  One thing the formula does not account for is added weight and a loss of some aerodynamics.  Typically you'll want to go one gear set lower to account for this.  On most gear charts there is some leeway though.  Go down a set for more torque/power go yup a set for better mileage.

[dan684]

Hmmm, my 4.10's feel just fine in my yj. Maybe off road it will be a bit different. I haven't gotten to wheel with it yet so who knows.

I do agree though... this post is a bit out there and random.

everything he posts is a bit wierd and random

[chardrc]

at least it is a little less random than his last post about i still don't know yet...