CycleOps Jet Fluid Pro Power Curve
Cycling outside isn’t always possible or desirable, particularly in the dark hours of winter and an hour on the turbo is better than not going out at all. A structured training plan indoors on the trainer can actually be better than an outdoor ride with no plan or aim… but this post isn’t about the virtues of indoor vs outdoor training!
Structure is very important when training indoors and training by power is the most effective method for gauging intensities that will help you improve and work towards your goals, and for those on a budget, “virtual” power is possible on many trainers, even on the popular CycleOps Jet Fluid Pro with the help of 3rd party software such as TrainerRoad or Zwift.
As there are no variables to overcome such as gradient or headwinds, the power output on the turbo trainer is directly correlated with speed, assuming you keep the rolling resistance and the tyre pressures the same. On the CycleOps Jet Fluid Pro I run 100psi in the rear tyre and clamp the wheel down with two ‘clicks’ of the tightening screw. Keep this the same each time and you have a reliably consistent measure of power.
Virtual power output will always be a rough estimate without a proper power meter, as it doesn’t account for things like the smoothness of the hub or the roughness of the tyre, but gives a good approximation, particularly if you use it as a training aid and don’t compare the numbers to other cyclists.
The Jet Fluid Pro has a power curve profile that increases roughly in line with the resistance you’d find on the road. CycleOps have published a very small, grainy graph of the power profile which is difficult to read, but gives a good idea of the power output for any speed. TrainerRoad have taken this a step further by creating their own power profile with a calibrated power meter. The two do differ somewhat, but having tried both, I’m finding the TrainerRoad version to be a better approximation based on my riding experience and a more accurate representation of the power I’m probably putting out. Anyway, here are the formulas for the power curves and you can plug the equations into a spreadsheet to give you a set of powers for any given speed.
The formula for the CycleOps Jet Fluid Pro manufacturer’s power curve is Power (W) = 0.0000586x4 + 0.02151x3 + 0.05665x2 + 3.9453x
The equation for the TrainerRoad power profile is Power (W) = 0.0001217x4 + 0.01347x3 – 0.01331x2 + 4.3669x
where x is speed in mph.
Using these figures you can effectively train by power, which is better than heart rate training or perceived effort. Even if they are not 100% accurate you can still get excellent results by determining your FTP and devising a training plan from them and then seeing your relative progress over time.