1.75ish gear ratio?

[colbystephens]

ok, so i was checking the gear ratio in my front ten bolt today as i am needing to go pick up a rear end for my truck, and when i did the basic spin the wheel once and count how many times the drive shaft spins trick, it only spun about 1.75 times. did i do something wrong? i don't think a gear ratio that high was offered in our trucks. what do you think?

colby stephens
www.web.pdx.edu/~colbys

 

[BlitzK5]

Yeah I tryed that method once before too and the driveshaft hardly spinned. So I pulled to cover and checked the ring gear to find out. The 14 bolt i got turned out to be 3:73. Most stock blazers were 2.73's or 3.08's.

 

[colbystephens]

you give me hope, but how does that work?

colby stephens

 

[4xcrazy]

if you are spinning only one tire, you have to take into consideration the spider gears spinning as well,,someone else will get in here and explain it some more.

 

[colbystephens]

maybe that's the case - i only had one tire off the ground. i'm not too familiar with the mechanics of differential gears . . . - yet.

 

[BlitzK5]

There will be a GM number then 4 numbers after that on the side of the ring gear. Take the first 2 numbers and divide and that will be your ratio

 

[colbystephens]

yeah - i've read about that, i just didn't have the time to pull the cover while i was near my truck today. it's about an hour away from home and i was driving thru to pick up parts to take to the machine shop.

 

[tRustyK5]

Spin the tire twice. I'd guess you probably have 3.42's though.

Rene

 

[Dallin]

tRustyK5 is right. With an open diff you need to spin the tire twice if you keep the other on the ground. If you spin both tires at the same time you only need 1 rotation. 1.75*2=3.5 probaly 3.40