This question comes up a lot. At the MVPA convention in Pleasanton, California I had the opportunity to have three examples of combat wheels on display. One from a halftrack, one from an M10 ammo trailer and one from an M8/M20 Grayhound. Here is what I found.
Measuring the back spacing:
The M10 ammo trailer and the M8/M20 have the same deeper back spacing of 9-1/4inches.
The halftrack has a back spacing of 8-7/8 inches.
Here is how to measure back spacing.
Steve A.
