I know Speed on a Turbo Trainer doesn’t really matter from a training perspective. I just need some help understanding why Speed varies so much from one trainer to another. I have recently started using a KK Road Machine (Dumb Model). It’s an amazing trainer and gives me a real good workout and a real good feel. My old trainer was a Elite Mag Trainer with 5 resistance settings. My wife uses an Elite Qubo Digital. There is such a massive variance from speed at similar power (Powertap pedals) and cadence from one to the next. A full out kick on the KK I would do well to get 28 - 30 mph yet on my old Elite I was getting 40-45mph (unrealistic I know).
Just can’t get my head around this?
There’s your answer. Different levels of resistance to spin the drum, so different wheel speeds. On top of that the magnetic resistance unit puts a constant amount of drag per rotation on the drum, yielding a linear power curve, while the fluid in the Road Machine resistance unit actually drags the drum more the faster it goes. That’s where the ‘feel’ of it comes from, at low speed there is little drag and it will happily coast along but at high speed any coasting will see speed drop quickly.
Consequently, at high power the wheel speed of your old magnetic trainer would be much higher than with the new Road Machine.
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@matthew.weigel has it right.
To state more simply, the power resistance curve of the trainers are all different.
The power curve is the relationship between wheel speed and applied resistance. Different trainer resistance units have different curves.
Magnetic units are generally a linear progression. Fluid units are generally progressive (non-linear).
So, the speed of each at any set resistance is bound to vary.
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I see now I think. I do believe the KK Road machine is much closer to what I would expect on the road for similar effort (maybe slightly under) and the old one was way off and made me feel like I was training like a pro. On the KK no matter what workout I do seem to average around 16mph. Anyway I know it doesn’t matter, I’m gradually getting faster and stronger. It has an impact on Annual Miles Target but if it makes me go harder and faster on the road it will compensate itself. 
Your response is greatly appreciated guys. Thanks.
Yes, the KKRM is one of the best trainers for several reasons. The power curve is something they spent years developing with a goal of replicating the feel of road riding, and they did a great job with it. It is highly regarded for this very reason (along with it’s nearly indestructible nature).
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Good choice of trainer then. Thanks very much to Trainer Road for the initial advice and recommendation on the KK…
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