I have a decent used Ruckstell recessed 40 tooth crown gear marked "40-13". From what I've read, these crown gears can be used with either the 13 or 12 tooth pinion so if it's used with a 12 tooth pinion it will have to be located slightly closer to the driveshaft center line than if used with a 13 tooth pinion (as the 12 tooth will be slightly smaller in diameter than a 13 tooth pinion). Can anyone provide the measurement for the difference in diameters between the 12 and 13 tooth pinion gears? I'm assuming I'll have to increase the shim set on the left side and decrease the shim set on the right side by the same amount, and not put any shims under the crown gear. Thanks in advance, Bruce
You'll have to get inventive to move the ring gear on a ruckstell because of the ball bearing on the left side. Perhaps uncle Stan can share his favorite method.
Thanks for the input Mark, but the only Ruckstell part is the 40 tooth crown. The rear end is basically stock Model T except for a Fun Projects pinion bearing setup and Lockwood outside rear brakes.
The diameter is the same so no shimming of the ring gear. The tooth shape is the only difference between the 13 and 12 tooth pinions