PDA

View Full Version : Suggestions..on final drive ratio


Kinslayer
11-02-2007, 10:12 AM
I was running some numbers on a project i've been thinking about...would like some advice on final first gear drive ratio, i've calculated it out to about 56.7:1 at the hub.. I know a stock pickup low range is usually in the 30s to 40s, so would 56 be low ENOUGH, given an automatic tranny?

Kinslayer
11-02-2007, 10:28 AM
Oh, and yeah I read through the other thread like this, heh. I know everyone will suggest 100+:1, but like I said, 75~:1 worked extremely well with 33s, and my heep is stock reduction (whatever it is with a 231) with 32s and I have no issues with 1st gear. I guess my real question is: with an autobox how much can you depend on the 'budget granny gears'?

not certain on my tire size yet but they arn't big-uns.

B
11-02-2007, 10:41 AM
the 231 is 2:72 to one ... the auto give u lot's to play with going up the down side is comming down ... when it will want to run on because of the high first gear in the auto ....

Kinslayer
11-02-2007, 10:47 AM
the 231 is 2:72 to one ... the auto give u lot's to play with going up the down side is comming down ... when it will want to run on because of the high first gear in the auto ....

not talkin about a 231 budday..remember what I was talking about last saturday?

I did some research, the ratios in the drivetrain i'd be running are:

tranny:
1st gear: 2.810
2nd gear: 1.549
3rd gear: 1.0

't-case': 3.950:1

I wont mention the axles because that would give away part of my project, although if you take those numbers and the number I gave up above you could figure it out on your own, heh.

Kinslayer
11-02-2007, 11:52 AM
Hmm..did some more calculations..looks like my 1st gear at 1000rpm will come out to about 1.6 mph (2.57kph) before the autobox effect, shouldn't be too shabby