campfiremaster wrote:the bike when in tow will center to the axle & trailer
If you mean to put the middle of the bike over the axle, I don't think that's good enough. It's reasonable to assume the centre of gravity of the bike, empty, is about in the middle of the wheelbase. But this point needs to be placed forward of the axle - as a rule of thumb, the midpoint of the bike's wheelbase should be forward of the axle by at least a tenth of the trailer's axle-to-hitch length. This might be as much as 10-12 inches.
This position means that when the bike is added to the trailer, it will add about 10% of its weight onto the hitch (and so 90% onto the axle), which is what you want for good trailer stability.
Andrew