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Should be delivered tomorrow, anyone got one of these and use zwift, any good? Cheers
https://zwift.com/hardware
^ will tell you whether it's zwift "approved" (ie if they already have an estimated power curve for it)
I think that even if it isn't officially supported you can tell zwift its a similar trainer and enter it as that. Your watts won't be accurate but that's a moot point anyway.
You won't be listed in some race results etc and it won't ramp up the resistance via zwift of course but on the whole it should work matey. I use a cheap cadence sensor and a hr sensor too but that's very much optional.
It will work, but not ideal. The resistance in the trainer varies depending on the temperature of the fluid. As you put more effort in the fluid heats up and you need less power to maintain the same speed, so not great for structured training. As a basic trainer to get you on Zwift it will be fine, just don’t read too much into the estimated power numbers.
The resistance in the trainer varies depending on the temperature of the fluid
Is this strictly true? Kinetic claim their fluid is 'thermodynamically neutral' and that it remains stable during workouts. I guess they would say that but their statement is pretty unequivocal:
"Kinetic uses a thermodynamically neutral medical grade silicone fluid in our trainers because it provides consistent, repeatable workloads and is not affected by temperature."
Others claim something similar. Anecdotally (other forums etc.) it seems to be that once the fluid warms up the resistance actually increases a bit, although I'm not sure I believe that, maybe something to do with any air in the chamber emulsifying with the fluid. I know on my Kinetic you are supposed to do a warm-up for 10/20 minutes before 'virtual power' is accurate.
Personally, I notice that my speed tends to creep up during a workout, for a given RPE/heartrate, so I agree something must be drifting, but there's other affects in the mix like tyre temperature and roller temperature?
It’s something I’ve been conscious of too. I have an Elite ‘dumb’ fluid trainer which I use for trainerroad with speed and cadence sensors. The accuracy of the power readings doesn’t bother me as I keep the set up the same so it’s at least comparable but I do feel some hard intervals get a bit easier further on into the session. However, this may also be because I’ve warmed up as well - it takes me a while - and I can always up the percentages of the interval if necessary.
I do feel some hard intervals get a bit easier further on into the session
For me it's whichever interval co-incides with track 6 on the Chemical Brothers 'Surrender', I feel like Andre Griepel for that interval usually!
My experience has only been with the CycleOps Fluid, so I am not sure if other brands are affected by this variation or not.
For a while I used a Powertap rear hub on the trainer, which gives a consistent power reading. At low power efforts wheel speed and actual power would correlate, on harder efforts it was noticeable that the speed would have to change to maintain the same power reading. Over Under interval session would really show this, on the unders everything would be consistent, on the overs (maybe 300w for 2-3 minutes) speed would drift away from the power. Once I was back in the under interval things would go back to normal. I did have some power and speed graphs saved that showed this, but no idea where they are now.
Did you ever figure out how much of a creep there was? e.g. how much did you have to compensate for the loss of resistance in km/h?