I have a Magnus 20570 smart trainer connected to a ANT+ dongle on my PC which then runs Zwift.
When on the trainer I feel like I am putting in far too much effort for the output I am seeing in the Zwift application, I try to keep my cadence between 70-80 which seems to equate to around 80-100w power with my watts per KG sitting around 0.8 - 1 depending on the activity I am doing, this tends to increase to around 1.5 going up hill because I am on the heavy side, the stats put into Zwift for weight and height are also accurate as I also understand this has a direct affect.
I’ve done a FTP Test and recalibrated the trainer (via the Saris utility application) as well as a first point to see if I can resolve this issue but I feel like this has made it slightly worse, to my knowledge the FTP test only has an affect on the training programs which I don’t do and the calibration on the trainer is what should then have an affect on the power I output in game (please correct me if I’m wrong).
Is anyone else having this issue, I was using a dumb trainer and appreciate it’s not as accurate but my stats from that where avg 157w and 68 cadence. I know there will be a variance but that big seems wrong.
-Dumb trainers are very inaccurate. Really. Just because some curve in Zwift…it is still inaccurate UNLESS you have compared to pedal/crank/spider power meter…which most likely you have not. Otherwise you would not be using a Dumb Trainer profile.
-Calibrate within the Saris or Rouvy app only. DO NOT USE ZWIFT TO CALIBRATE. (you do not mention which method but this is important)
-Compare power numbers through a couple of different apps: Trials of Rouvy or IndieVelo or whatever.
-Check your trainer resistance setting in Zwift…load up a course and go into Menu/Settings. Standard is 50% but perhaps got changed. 100% can be a shock if not used to it.
Thanks for your reply, I’ve edited my post to include how I recalibrated my trainer, when I did my recal via the Saris app it told me to get to 21MPH/34KPH and then coast, I assume that what this does is tells the trainer what sort of wattage I put through to the output the correct resistance to the trainer.
You’re correct I have not done any other comparison against my dumb trainer other than just comparing the stats in the app from when I was on the dumb trainer to what I am doing now on a Smart trainer.
I will have a look in the Zwift app now and see what the settings are, if this is already set to 50% is there anything else you could suggest *Edit - I’ve tried to locate the Menu/Settings option but there is nothing about % there for resistance.
It’s impossible to say if it’s wrong. Getting a big reset after switching to a smart trainer is pretty normal, but whether that’s correct in your case is impossible to say unless you have a power meter to compare to the trainer. Wheel-on smart trainers are especially vulnerable to misreporting power due to improper setup such as roller tension, tire pressure, tire type.
Appreciate your reply but the fact there’s such a big variance from the use of a Dumb to Smart isn’t the primary issue as I expect there to be a difference because of the nature of a dumb trainer.
My main issue is why it feels like I am putting in so much effort for so little output within Zwift itself, I can go outside and average around 15mph without any real issue for 20 miles, but put me on Zwift for say Volcano circuit and I am struggling to stay above 12-14mph on a 5mile circuit. To me that feels like there is an issue somewhere but I cannot work out where.
Probably something about the trainer or how it’s set up. The usual outcome in Zwift is you go faster than IRL. Zwift trusts whatever power the trainer reports, unless you go over insanely high boundaries with the power.
Thanks again, when I first had the trainer the calibration for it was to get to 34kph/21mph and then let is coast, it then provided me something called a rolldown which I believe went from 3.01seconds when I did it the first time to 5.01 when I did it the second time, I assume the higher wattage I put in the longer the rolldown would be. I guess I just need to look around on the Saris forums as well to see what those numbers mean to give me a better understanding of what is going on.