I basically have the same trailer you are asking about, a 2 place snowmobile trailer. I put Load Range 'C' tires on it(Northern Tool). I have had the chopper and 2 baggers on the unit, and drug it from Tennessee to Mn. I too get concerned about the smaller diameter tires(RPMs), but no probs in 8 yrs. Do you have bearing buddies on it? They are avail at Northern, also.
But enclosed is GREAT for above mentioned scenarios. Just don't have the $$$, plus I haul lawn equipment on mine.

 

I don't believe in bearing buddies, as they are often mis-used. They were originally designed for boat trailers to maintain positive pressure in the hub to keep water out. That's besides the point... I repack my bearings every year anyway!! I'm not worried about the bearings as much as the tires!

The trailer would be for weekly trips (leave Monday, come home Friday). Here lately, I have been out of town every week, but I won't be taking it every week.

 

&nbsp\\;&nbsp\\; I tow my bike on a single rail open trailer (we supposed to keep our bikes out of the 'elements'?....I thought we lived in the elements?)
&nbsp\\; Put a can or two of 'detailer' in your car or truck.&nbsp\\; Wipe the bike down every
once in awhile.&nbsp\\; You'll be fine.