deVries wrote:Because you are pulling a trailer & 85-lb dog, you can not or should not use a front wheel mounted motor.
While it can be more difficult to handle a trailer loaded with a wiggly dog using a front motor, it's not necessarily a problem, depending on the balance of weight in teh trailer and on the bike.
In my experience with the 100lb Hachi or Nana (or sometimes the smaller and lighter Bonnie or Fred), when there is too much weight forward of the trailer wheel axle, and it pushes down too much on my hitch that is *behind* the bike rear wheel axle, it will take enough traction off the front wheel that the front hubmotor can have troulbe with spinout on startup, and sometimes traction in turns.
But using a trailer and bike that allows attaching the trailer hitch *forward* of the rear axle, like the 2-kid Bell trailer with a kennel top rather than the cloth kid-housing, that problem doesn't happen. It allows full weight to remain on the front wheel in almost all situations--the exception being an extreme turn at higher speeds, above 15MPH or so. Since it's really hard to turn with a trailer containing a wiggly dog at speeds above 5-10MPH anyway, this isn't much of a problem.
That Houndabout trailer is identical in frame layout/hitch/wheel style to the 2-kid Bell trailers. So it can work just like mine, with front or rear motor, depending on the rest of the weight balance of bike and trailer.
The weight of the hubmotor actually helps with front wheel traction in turns and such with the trailer attached, in most cases. When going too fast, the wheel scrubs instead of gripping and makes it pretty tough to control the turn, so it ends up far wider turning radius than normal, but the weight of hte motor actually helps this a little bit. Any othe rweight causing equal response, placed forward of the rear axle, would also help. (less weight is rquired the farther forward it is placed).
So it kinda depends on the trailer, the hitch placement, and the weight placement on the bike, for how it will behave with a front motor vs a rear.
I *can* say that almost always you will have noticeably better traction with a rear motor than a front, regardless of trailer or no trailer, with typical weight balances on a bike. If all the battery and stuff is placed over the front wheel (front rack, panniers, etc), then the traction in front would be enough better that it might be a tossup between front and rear traction. Depends on total weight balance.
All that said: Personally, having experimented with the identical motor first in front and then in the rear, I'd rather have a rear motor (which is why the upcoming Fusin review motor kit is a rear type), for most types of bike setups most poeple would use. I think you would probably be better off with a rear motor, as it simplifies quite a few "little" things, although it does complicate installation on some bikes (and thus tire changes and the like).