Overall Diameter "d9" G Sprockets

Hello Everyone,

I have a friend here in New Zealand who is gearing up to build from scratch a 1/5th scale model of a "D9G", he now has most of the dimensions he needs, however, as there is not any of these tractors in his area, nor is there any here anywhere near in my area either.
He would be most grateful indeed if anyone could measure up the overall diameter of a rear sprocket for a "D9G", and publish it on this board, the model will be automated with a small petrol engine and will also be radio controlled. He has already built from scratch two 1/5th scale model trucks which are both pertol powered and radio controlled. Again our thanks to anyone in advance for the requested information.

Sincere regards to one and all in the "CATERPILLAR" world !!!!

Alan T. Lewis
Christchurch
NEW ZEALAND