do any of you have the dif gear ratio formula handy? i have it but can't seem to locate it.

 

What "Formula"?

 

i want to change my gear ratio for larger tires and i want to figure out the rpm/mph. i want to gear it back to like stock gearing with the larger tires.

 

I forgot the formula, but with 35's it should be somewhere between 4.29 and 4.56 ratio.
I have 35's also and was looking at swapping to 4.56 to give me a little better off the line launch.

 

Its all good yeah i was looking at either 4.30 or 4.56 i rode in one with the 4.30 and it felt great. it cleaned up the shifting. i don't know about your's but mine (auto) after i put the tires on the shifting is just really goofy and i thought it was the tranny and all sorts of things. then i talked to the guy with the 4.30 and he said his did the same until he did the gear swap. he also told me that it helped with tranny temps i guess because it doesn't have to work as hard. i'm just wondering if the 4.56 would be to much gear. my pro comp 35's measure an actual 33.5. i just don't want to much gear to where my truck is running at 2500 rpm at 75mph. let me know what you think

 

([Tire Diameter] X [RPM]) / ([Gear Ratio] X 336) = MPH

([MPH] X [Gear Ratio] X 336) / ([Tire Diameter]) = RPM


If your stock gears are 3.73, then 4.10 is about 1% of low from stock. 4.56 would be a bit high for street use. 4.30 to my knowledge are not yet made for the AAM differentials. If you know somebody who does make the 4.30 let me know!

Brian

 

Should have listened in Math Class!

Old tire diameter divided into new tire diameter multiplied by existing gear ratio equals required gearing to maintain the same RPM.

Joe

NTD/OTD x EGR = RG

 

Living on the Island of Hawaii, we don't have any freeways here, only 2 lane highways. So getting up to 75mph or higher can be done just not for a long period of time.
4.56 is a bit high for freeway travel. But off the line launches will suprise alot of people from the stop light.

 

Thanks. if the 4.30 isn't avail i don't know what i'm gonna do. i could of swore that guy said he had a 4.30. i had 4.56 in my gasser to turn tires that measured 34.5 and they worked great.

 

inferno ram there is a 4.30 made for our trucks it is by yukon. I found it at our local offroad shop.