What would worry me is the max 45 speed. I have a small similar trailer where the week link in the crappy nonstandard Chinese bearings. I use it around town only and have still had bearings burn out. If you could up grade the bearing and go to larger wheels and tires it might work.  Pretty good price for an aluminum trailer. 

   Sounds like a classic case of "you get what you pay"

   I have built tear drops. I never trusted harbor frieght or northern tool.I always used a trailer from the salvage yard from an older model camper and cut it down to my liking.

   I built a teardrop on a Redtrailer. The standard 5x8 trailer came with wheels that were only rated to 55 mph, but I bought two "high speed" wheels and tires. I use the other wheels and tires for spares.

Those speed ratings were written by lawyers, not engineers.  With that being said, a larger diameter tire will cause less revolutions at any given speed, which is proportionately easier on the bearings.  I've drug a $300 HF trailer all over Texas at highway speeds with less problems than a bona fide boat trailer.  Install Bearing Buddies if you can and keep them greased and with the largest tires that fit under the wheel wells/fenders (or remove them) you'll be fine.  Also, make sure you torque/locktite the fasteners appropriately during assembly.

I have a dream that someday I'll have a yard that has a boat trailer, portable pizza oven, popcorn kettle and construction trailer modular system that uses the same fold-up trailer as the base.

i just bought the ultra-tow 5x8 trailer (i hadn't seen this post before buying it).  the "bed" of the trailer is 10" longer than the teardrop, but i will fill the gaps with two 1X6 deck boards.

i also bought a set of their "high-speed hubs", and i just bought a set of 15" wheels and tires.  (i bought 3 hubs and 3 wheels/tires so i have a complete assembly as a spare).

the rims on the 12" tires that came with the trailer are marked for 55mph.  so, even without upgrading to the "high speed hubs" the equivalent speed for 15" tires would be just about 70mph.

the only disadvantage i foresee is that there is no place for both a front-mounted storage box and the spare tire.  i will build the box from scratch so at the moment my plan is to mount the spare onto the front of the box.  i will make a prototype box out of cheap plywood to make sure my plan makes sense.

i was dissuaded from buying the CLC trailer because it only has 12" wheels (and the price!). 

ken

   i forgot to ask if you've finished the teardrop?  i'm a couple of weeks away from applying the varnish.  how many quarts did it take?  i'm planning on 4-5 coats.

   Wow!  This is an old thread and I'm a new builder. I'm interested in anyone's experience with the Ultra-Tow trailer; specifically any modifications to the tongue or axel/wheels required.