Tractors come in quite a few wheel bases, over the road units usually will have the longer frames due to big sleepers, In my opinion its always best if you do not have to cut and stretch a frame, and adding frame rails after the drivers is pretty easy and not to much money to have a frame shop handle it if you do not want to do it yourself. 2x2x3/16 tubing is going to be pretty heavy (runs 4.3 lbs per foot) and expensive. I am planning on using 1-1/2" for the walls with some heavier tube at the corners and around the roof for added shear strength. Seems like the most popular roof materials are aluminum, rubber (EPDM), and fiberglass. Each has definite good and bad traits. Personally I tend to lean toward 60mil EPDM rubber, installed properly is a good 20+ year roof. The company I work for builds mobile office trailers, and we have hundreds of units out there and the rubber has hold up the best, and is easy to patch. It is easy to install and seal. Aluminum is also a good choice and is available in sheets or in a full length roll.
|