My calipers' batteries are dead t the moment but, having worked with many of these drives in the past, I believe that the wheelbase of a single truck (not the wheelbase from truck to truck) is shorter than the truck of, say, a Lifelike switcher. I never measured them, but I was able to tell when attempting to use sideframes from a LL switcher, or one of its successors, over one of these trucks (I used MT SW1500 sideframes on my SW1500 bashes using these drives/trucks). The bearings don't quite line up. It's not terrible, but it is noticeable if you look closely. Hope this helps!