Thud....I've heard them called "Michigan Millipedes" and know exactly what your talking about. I think though if you'd reconsider.....a gross weight of 105 thousand your going to be able to haul more with another axle vs. what it weighs. General rule I understand is 20,000 on each axle except the front....15 or 17 on it. So say your going to haul 80,000 on 5 axles but bridge laws permit 100,000 so add another 1000 lbs of dead weight to the truck with an axle so you can haul another 19,000 lbs legal seems to make sense to me. No....I don't know what an axle weighs to be real honest with rims,tires,gears,housing and oil but I highly doubt it's over 1000lbs. My Pete with a 48 foot Flat on 5 axles weighs in empty (full tanks of fuel) just around 32,000. I'd guess with another 5 axles under it I would still be under 40,000. Of course....this is nuts for a grain farmer I think. The up front cost could never be returned on a purchase vs. a lease or custom hire. A trailer like that is going to cost you over 50,000 dollars when you get done so practicality rules that idea out I'd think....least on my end of the stick. While were on the subject though....I loaded the living heck out of a 42 foot Merritt trailer this summer and gross was way over 80 thousand (I'm not going to say exact what) and I had on 1200 bushel. What are those michigan millepedes pulling for trailer lenght that they are getting out 1400 bushel'sIJ