gearing ratios

[7dhamper]

My stock gears are 3.73's. I want to put in a 4.11 rear end with posi and discs and a 4 link outta a '97 Trans Am. I want to use an 18X8" front and 20X9" rear wheel combo. A 225/40YR18 BFG KDW is 25.1" tall divided by my 3.73 front end = 6.73. A 245/40YR20 is 27.7" tall divided by the 4.11 = 6.74. Is this 1/100 of a difference enough to destroy my AWD transfer case? Since the front are a little too small for a perfect equation, will I be pushing the front or pulling the rear? Which would be worse to do? Where would I look for this type of info? Please give me a lead! Thanks, Joe.

 

[FLSY2730]

Did you change your gears because all syty came with 3.42s, and fbodys dont have 4 links, they have trailing arms with a panhard rod if thats what you mean. The difference you have there should be fine , you could adjust the air pressure between front and back to make up the diff.

 

[7dhamper]

What is that little green allien doing in my post? Right on my 20" rear rim? Is someone mad that I want a larger rear rim? Well, thanks for the input. i hope you are right. Ive looked everywhere for GM's tolerances specs and found nothing. So the F body is a 3 link? is that an adequet rear suspension? 2 ladder bars and a panhard bar? I can bolt the ladder bars to the leaf springs brakets in the front, and use an S-10 Extreme's pumpkin housing with the 3rd shock stud on it for my panhard bard and just mount the other stud to the crossmember that the bags will mount to when I step notch the frame. Do I still need the other 2 links of the 4 link set up when using this type of suspension? or is a panhard bar good enough to prevent wheel hop?

 

[keith455]

Speaking of gear ratios. How do you check the ratio of the front diff??
I know it's supposed to be 3:42 but when I turn the yoke and count how many times the axle rotates it's different every time.
Are there some markings on the diff that might help me?
Thanks.

 

[ParTyBoy]

Speaking of gear ratios. How do you check the ratio of the front diff??
I know it's supposed to be 3:42 but when I turn the yoke and count how many times the axle rotates it's different every time.
Are there some markings on the diff that might help me?
Thanks.

That's a TurboTony question :wink: