I need a 54" to get around the flatbeds I tow with. 36" might work with a typical full size SW rig. BUT, add a camper and the supports, or a dw, or _________.
For OP, ONLY real way to know how big a rig you need, is to take and make up a plan of where you want to keep things inside, how, in what kind of containers things are held in.
Examples, if you think 6' is wide enough, the inside is probably 5' 10" due to sides. So if you are thinking 2' for shelves per side, 2' of walk way. The walk way s only 22". Or if you get 25" containers, put them long way per width of trailer, you are now down to a 2" width pathway. So a 7 or 8' trailer may be a better option. BUT, now you ahve probably added another 200 lbs to the trailer. Which if you get one with say 2 3500 lbs axels, 7000 lbs plus say 1000 lbs of HW. Giving you a max 8000 lbs of total trailer and cargo. Tare of trailer goes from 1200 to 1400 lbs, You guestimate initially 6800 lbs of cargo inside.....if you add said 200 lbs ot the hitch, you stay under the axel ratings. or need to go with 2 4000 lb axels.
You can not just GUESS or otherwise what sized trailer you need. Be it cubic feet, width, height, rated gvw.... guesstimating is good, then add some lbs of air for cargo weight, maybe some inches to width if possible, length, height etc. THEN, and ONLY then, you may not need to expand later. WIth this said, having to go bigger, expand if doing a business, can be a good thing too. Or you may find you want one trailer going one way, a 2nd another way. In which case, having two trailers, one smaller, the other larger per say is good also.
Also, MANY cargo/equipment trailers are sold by payload. This payload is the sum of the axel(s). With a small prints note of " must have adequate hitch wt" ie weight of trailer. If you are assuming say 10% HW on the above 1200 lb trailer, with 7000 lbs of axels, they may say, you have 7000 lbs of payload, but you need 1200 lbs of HW. NOT, the 700 or so you may be thinking. SO you are 500 lbs overweight per manufacture specs. You will again need a trailer with the 4000+ lbs axel option. I ran into this specing an equipment trailer. I was putting 12000 lbs including a 1000 lbs of air for stuff I could not think of, they tried to sell me a dual 12K trailer, with 4500 lbs of HW needed. I wanted a dual 7 or 8K trailer so I only needed around 1600-2000 lbs of hithc with a total trailer weight of 16000-17000 lbs.
A lot of things many of us are not positive about. Watch out for sales snakes.
Marty
