Originally Posted by
Xherion
In theory, but the reality is the viscosity of the resistance fluid changes with temperature. This generally is a problem when the trainer is cold up until the fluid warms and then can be a problem again after a certain duration and speed. Many of the mainstream fluid manufacturers attempt to compensate for this with various different design and cooling mechanisms, but I'd take a strain gauge any day over a prescribed resistance curve.
I should have been more specific.
The Kurt fluid trainer I use, is filled with a "thermodynamically neutral liquid silicone", so power estimates are consistent across changes in the liquid’s temperature.
I did a lot of reading before buying the "InRide" power meter for my Rock and Roll trainer.
For $50, I added on a "power meter" that has been shown to be very accurate.
I don't think in any way I would be "much better off" with a $600 Stages unit for my indoor winter riding.