I checked the parts books, service manual, custom track service handbook and my after market reference for the D9G and it's not in any of them.
Took the numbers off a idler that I have--Here goes--app.37 inches across-
117 inches in total dia,--21 inches width--blocks are 6 3/4 x 7 inches.
Hopes this helps
Hello Ols Magnet & Al Engines,
Many many thanks to you both for your efforts and assistance with my search for the dimensions of the "D9" Series "G" tractor front idlers. I will certainly pass the measurements on to the person who intends building from scratch a 1/5th scale working replica, which will be radio controlled.
Once again my most sincere thanks. GREAT SUPPORT !!!
Sincere regards
Alan T. Lewis
Christchurch
New Zealand