Understanding resistance on classic trainers

(Allan Strydom - SZR (C)) #1


I’m busy doing research into exactly what equipment I’m going to purchase in order to be able to use Zwift correctly and I’m battling to find sufficiently detailed information on how resistance and speed work if you use a classical (non smart / no power meter) trainer with Zwift.

I’ve read all the guides on the site, been through the knowledge base, read many forum posts etc but the specific details on exactly how it works just don’t seem to be available anywhere.

I’m in South Africa and equipment is pretty expensive here so buying a smart trainer with a power meter or even a standalone power meter is prohibitively expensive and it therefore makes a classical trainer / speed sensor combo far more appealing.

My confusion is specifically around how the resistance levels work in that case. I’m looking at buying a Tacx BlueMotion with 10 resistance levels for example and everything I’ve read so far regarding Zwift seems to imply that you have to set your classical trainer to ONE specific resistance level as recommended by Zwift and leave it set to that.

That being the case, I’m assuming that you would then have to manipulate your gears to artificially increase the difficulty of your ride and the amount of power you need to generate to turn the crank ?  But I can find nothing that confirms that this is the intended approach. If the trainer is not smart, and the resistance level is never going to change, then I can’t see any other way of doing things, but I’d like clarification on this point.

I’ve already seen forum posts by other Zwift users stating that the recommended resistance level for certain trainers is too low and they cannot generate enough power at that resistance level, in any gear, to make their rides worthwhile. Obviously that also concerns me because I don’t want to spend R 6000.00 on a trainer only to discover that the only calibrated resistance level supported by Zwift doesn’t provide for adequate difficulty and high enough power generation during a workout.

So in summary:

  1. What exactly is the story with resistance levels and classic trainers ?

    Do you, or are you planning to, support multiple different resistance levels for different trainers ?

    Is it true that currently only ONE specific resistance level is supported per officially supported classical trainer ?

  1. Is it your intention that players use their gears to artificially influence difficulty and power generation (given that no smart trainer is attached and resistance cannot therefore be modulated by Zwift dynamically) ?

I would really appreciate some technical level feedback on this and I’m sure many other Zwift users would probably find the information useful.

I would also like to suggest that you update your knowledge base pages to specifically address these questions and to include specific detailed information about how exactly a classical trainer coupled with a speed sensor is expected to work and should be utilised in Zwift. Currently there is a big gap in your knowledge base regarding this. Also provide explicit information on resistance levels and exactly what Zwift expects / recommends in that regard.

I’m really looking forward to getting Zwift up and running and from what I’ve seen so far it’s a great product that can only get better.





(Mark Hewitt) #2

Yes, with dumb trainers you leave it at one specific resistance level, one which Zwift knows the power curve for, and you use the gears on your bike to vary the effort therein. Therefore if you want more power on the hills you need to shift to a harder gear, i.e. the opposite of what you’d normally do.

Can you get a Tacx Vortex or Flow where you are? They are decent value smart trainers.