Cascade Crew

Quasi-Traction · Posted: Wed May 23, 2007 3:34 am Post subject: Idea about Gears....will it work?

So I've been doing a little recreational investigating about the rears on these cars, and there was just something I've been wondering:

In relation to the Ring/pinion and the actual gear ratio itself...I wonder why more options weren't explored, especally with the 3 series carriers. Here's what I mean:

GM offered these gear ratios on 3 series carriers

3.23.....42 tooth ring, 13 tooth pinion
3.42.....41 tooth ring, 12 tooth pinion
3.73.....41 tooth ring, 11 tooth pinion

I came up with 2 others:

3.15.......41 tooth ring, 13 tooth pinion
3.50.......42 tooth ring, 12 tooth pinion

is there a physical reason (thickness, profile of the ring/pinion gears?) why those combinations wouldn't work?

They could have used 3.15's in the 5 speed TBI cars and not had to put a 2 series carrier in.

Just thinking out loud here....

blue89 · Posted: Wed May 23, 2007 7:19 am Post subject:

probably because the speedometer was gear driven. If you toss too many options in there, the speedo gear selection would get real funky? I too have wondered why it wouldn't work.

Twilightoptics · Posted: Wed May 23, 2007 9:38 am Post subject:

The 3.15 and 3.50 are those actual gear sets or did you just use math and run a mis match ring/pinion?

If mis match the wont wear right. Each set of ring/pinion is machined together.

Also what's the point of making a 3.15 if you have a 3.08? and a 3.50 when you have a 3.42? Would make absolutely no difference to the driver or milage.

Xophertony · Posted: Wed May 23, 2007 10:39 am Post subject:

i think his point was more of why do you need 3.08 when you have 3.15 then you would not need 2 series carrier for the 3.08 ratio.

Dewey316 · Posted: Wed May 23, 2007 11:27 am Post subject:

they probably won't mate up at all. Remeber as the ring gear changes, the diamater of the pinion gear also changes, I bet the teath won't come close to meshing.

blue89 · Posted: Wed May 23, 2007 12:07 pm Post subject:

Dewey316 · Posted: Wed May 23, 2007 1:01 pm Post subject:

that is what I get for being in a hurry to type something out.

Quasi-Traction · Posted: Wed May 23, 2007 1:09 pm Post subject:

I figured it be something about the thickness and profile of the ring and pinion teeth that would cause a problem, thus why GM didn't do it from the factory.

that more or less answers my question.

blue89 · Posted: Wed May 23, 2007 1:17 pm Post subject:

isn't the cascadecrew philosophy to completely hijack every other thread though? lol.

Dewey316 · Posted: Wed May 23, 2007 1:22 pm Post subject:

I don't know if it is more of a phenomenon, or if it is an actualy philosophy. Either way, hijacking happens.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

I was just comparing ring gears from some 2.73's and 3.73's. They look to be identical besides thickness.

But Paul answered your question already. Only need about 5 ratio's to cover all performance or economy goals the manufacturer ever had for these cars.

QwkTrip · Posted: Fri May 25, 2007 3:58 pm Post subject:

You can't mix and match the gears because the teeth won't mesh due to incompatible diameter or wrong pitch. Just adjust tire size if you want to tune the gear ratio to that fine a level.