Hi Paul,

Our cost for the RX8 rear counterweight, N3Z2-11-52X, Our part #
11458 is $109.70.

It would certainly be possible to machine a "drive disc" with a ring
gear mounted. In modest quantities, it might come out a bit cheaper
than $380.00 with the counterweight and ring gear, but with what bolt
circle? What disc stiffness is necessary?

Jim Mederer

Not much disc stiffness. No real loads on it other than
the starter and the torsional. Can get you get ring gears?
Seems like 3/16th mild steel would work. Perhaps you can find
some one to stamp press it out of 3/16th mild steel or even
normalized 4130. It needs that recessed center.
AC Spruce sells 18" by 18" .190 thick 4130 for
$90. If you buy 18" by 36" .190 4130 that will make three for $120
total or $40 material cost each and have a lot of 6 by 12 pieces
left over.

The stamp press tooling would be easy to machine on a large lathe. It does
not need all the holes the stock one has. Just the four 3/8th to
mount Tracy's torque isolator. The customer can drill those. Weight
is not an over riding concern. The stock counter weight is cheap
enough. The kit will sell for the next five or ten years.

Paul Lamar ...No rotor no motor.