Dolly sets
IronViking, the photo you posted is an M832 dolly set. Even though it is a 690/691.
The M832 applies to the entire dolly set, the front half is an M830 and the back half is an M831.
It can handle a 5 ton load. It is not built to move shipping containers, rather it is for hauling standard 12 foot military shelters. The same shelters that fit in a deuce or 5-ton bed. The M832 has standard deuce rims and tires and carries no spare because you are supposed to use the deuce spare. If you tow it with the 5-ton, then you should carry an extra deuce spare with you.
The next smaller size is the M720, built to carry military shelters weighing up to 3 tons. The M720 has (I think) 7.50x16 tires on it.
The M832 and the M720 will carry the same shelter ONLY if the shelter has sliding adjustable bolt adapters. Ask me how I know!
I have added a picture of one of my M832's with an S-530 shelter mounted on it. I had to whack off one inch from the upright attachment legs on the 832 because the S-530 was designed to be towed with an M720. Clear as mud?
The original purpose of the smaller dolly sets was air mobility. If the shelter is on top of a deuce or a 5-ton, the load is too tall to fit in C-130's, C-141's etc. Get the picture?
-Sarge