Topic: SWAPPING FROM 31s to 32s or 33s or NOT ?

[Bounty Hunter]

No real difference, especially behind a 4banger.  Go with 4.88, anything else is a waste of time and money.

[Torch_Ind]

No real difference, especially behind a 4banger.  Go with 4.88, anything else is a waste of time and money.

how many times do we have to say it?   in the end if you don't want to take our advice it's fine...  just expect "I told you so's" later lol

[chrisfranklin]

4.88 and 33 is same as stock (assuming you started at 28'' and 4.10)
Your speed to rpm ratio is directly proportional with your tire diameter and inverse to the R&P ratio (1/R&P), which means the higher the number in R&P (lower gears) the more rpm for the same speed. the larger the tire diameter the more speed for the same rpm.

To compare them you can simply do simple math like this:
28/4.10=6.83
33/4.88=6.76 (1% difference vs stock)
33/4.56=7.23 (5% difference)
31/4.10=7.56 (10% off compared to stock).

That's a nice breakdown Sharp.  I bookmarked it

[quicksand]

4.88s it is, sounds good Mr Bounty Hunter. Now I just gotta save MO money. Please send any donations to --------------just kidding. OK so I need a LiL bigger lift, some 33x10s, and new gears. I CAN DO IT, YES I CAN !

[quicksand]

Hey just looked at chart again and that means right now I am 10% off with my 31s compared to stock, HUH.

[sharpxmen]

Hey just looked at chart again and that means right now I am 10% off with my 31s compared to stock, HUH.

yes, so if your speedo shows 60mph you're actually travelling at 66. Same for mpg, if your calculation shows 15 you're in fact at 16.5mpg (unless you changed your speedo gear). This is all based on having 28'' tires stock, not sure what they were on your year Jeep but probably close enough.

[Torch_Ind]

4.88s it is, sounds good Mr Bounty Hunter. Now I just gotta save MO money. Please send any donations to --------------just kidding. OK so I need a LiL bigger lift, some 33x10s, and new gears. I CAN DO IT, YES I CAN !

lol the donations 

[quicksand]

Yeah does changing the speedo gear have any affect on the jeeps brain or just gives your correct reading on speedometer only?

[AGUHR]

Any one know the % diff on 34's with 4.10 gears?

[quicksand]

Go to calculators at bc4x4.com they might have it, I am not sure.

[sharpxmen]

Any one know the % diff on 34's with 4.10 gears?

((34-28)/28)*100 = 21.43%

EDIT: since you're not changing the R&P ratio is all proportional to the tire diameter, i used 28 as stock but you can replace it with whatever your Jeep originally had. a more simple calculation would be 34/28=1.2143, that means that real speed = 1.2143 x indicated speed, same for distance traveled. Keep in mind that this is for the theoretical diameter, to get an exact calculation you'll need to measure the distance from the ground to the center of the axle for both stock and new tires (that would account for tire deflection as well).

[AGUHR]

Thats nuts - thanks.

normally just stay with traffic, now I'll have to pay a little more attention to my speed.

nice website by the way.

[Jeffy]

Yeah does changing the speedo gear have any affect on the jeeps brain or just gives your correct reading on speedometer only?

http://4bangerjp.com/forums/index.php/topic,731.0.html