The 18+ wheelers are
engineered for towing a SEMI trailer. A whole different ball game than adding a trailer on the rear end of a vehicle that wasn't designed to tow a trailer. The big rigs have the weight right over the drive wheels and the suspension is built for the load. The tractor has such heavy suspension that if you bob-tail (Go without a trailer) it will almost jiggle your eyeteeth, especially on a concrete road! The reason that truckers like the conventional tractors is that they have a longer wheel base than the COE (Cab Over Engine). Most now have huge sleepers which contribute to an even longer wheelbase. (Did you know that U-Haul won't even rent a trailer to someone with an Exploder? (er. . make that Explorer) See this page:
http://www.usatoday.com/money/indust...aul-ford_x.htm