<VV> choosing rear end ratio

[N. Joseph Potts]

One good answer to this question is in the catalog of one of our vendors
that sells it: Clark's.
     All automotive differentials contain a pair of what is called spider
gears (eye, not weye). These gears together impart torque to the axle shafts
while still enabling them to turn at different speeds, as they do whenever
the car isn't travelling straight ahead. Both of these (identical) spider
gears engage the gears that are splined to the inboard end of each axle
shaft.
     A four-spider setup inserts two additional gears in with the existing
pair to engage those same axle-shaft gears. The use of the four gears
instead of just two adds considerable strength to the spider-gear function.
The spider gears are subject to a lot of repeated stresses in use, and they
have been known to crumble without warning after a few decades of this (mine
did). They crumble that much sooner when subjected to abuse and/or the
stresses of racing. It's common for this event to damage other parts of the
differential, as you'd expect - this is well worth preventing if you have
your diff open. Merely renewing the existing spider gears probably does most
of that job.
     No other part of the differential is changed by installing this setup.
I installed it in my non-Posi 3.55 when I replaced my crumbled spider gears,
and the installation was very straightforward. I expect my four-spider setup
to outlast the rest of the car, and me, too.

Joe Potts
Miami, Florida USA
1966 Corsa coupe 140hp 4-speed with A/C

-----Original Message-----
From: virtualvairs-admin@corvair.org
[mailto:virtualvairs-admin@corvair.org]On Behalf Of RKAT
Sent: Wednesday, December 01, 2004 6:47 PM
To: 'Bill Elliott'; virtualvairs@corvair.org
Subject: RE: <VV> choosing rear end ratio

I have heard of the 4 spyder diff. How does it work? What is it's
purpose?

Thanks!

Ron Tinkham
http://www.ronsjeepjunk.4t.com/
Pine Tree Corvairs (in the works)
66 Corsa Convertible, 140, 4sp
Maine