Originally Posted by
cinegabe
I meant one roller per wheel, with the rear drum behind the rear wheel and the front drum ahead of the front wheel. Can you visualize that? Why wouldn't it work?
It wouldn't be stable - the front wheel would ride slightly up the front roller and the rear wheel would fall to the ground.
EDIT - if you had the rollers far enough apart, it might be stable, but then the bike would be sitting pretty low between the rollers and the force on the rollers would be very high.