I have a set of rollers and a single-speed road bike. My 80-90 rpm speed is 27-30 kph (17-19 mph). I feel like I would be more stable with higher rpm, but it's harder to sustain.
If I understand this, the source of the bike's stability is the gyroscopic effect of a spinning wheel. So there are few more variables to that, like a wheel's mass, or even distribution of the mass within a wheel body. For the reference, my wheels are 27" and 1.5 kg (3.3 lbs) each, and I'm 70 kg (154 lbs) myself.
Can you share an experience with the speed-stability relation of a road bike on a set of rollers?