I think the width of the HMMWV body is around 85 or 86 inches, and the width of the M101A2 trailer is 73.5" as per the TM. So the hard cover for the HMMWV will overhang the trailer by at least 6.5" on each side. I don't know what the length of the hard cover or the bed length of the HMMWV is, so don't know about that dimension.