Zwift on classic trainer with powermeter

Hi there,

I’m on my Zwift free trial at the moment, and climbed Alpe du Zwift today with my friends. My turbo trainer is an elite direct drive trainer and I use a powermeter, but the trainer is not smart so does not adjust resistance. I was quite happy with my time, and averaged 238 watts. However, because the trainer isn’t smart, I have free control over resistance up the climb, so I was able to hold 250+ (my FTP is around 250, so this is accurate) for most of it. I was wondering if I am at a disadvantage or advantage compared to my friends on smart trainers, or if overall, our results will be pretty much the same.

Thanks

Power is power. If you are using a calibrated powermeter you don’t have an advantage compared to your friends with a smart trainer. You put in the watts, and as you said they seem legitimate based on your FTP. If anything you are at a slight disadvantage since you have to change the resistance yourself with your trainer.
I used a similar set up for one off-season with an Elite direct drive trainer that sent power data to Zwift without Zwift being able to change resistance (the power meter was calibrated against a pedal power meter). I have since switched to a Kickr a few years ago, definitely an upgrade due to the ability to have Zwift change the resistance, AND I’ve never had anything go wrong with my Kickr. The Elite started to make noise within a few hundred virtual miles, I had to tear it apart to tighten the belt and shave down part of the housing.

Okay, thanks a lot for the detailed reply.

I guess the second part to my question - am I at an advantage being able to choose my cadence? Eg. If I’m getting tired, I can maintain my wattage just by spinning it out, with less resistance than there might be on a 15% gradient in real life. So if I choose the smallest gear, am I at an advantage because they’re trying to fight a predetermined resistance set by their trainer? Hope that makes sense.

Thanks

I’d say it’s an advantage. When I made the switch from a set up like yours to a smart trainer I found the big/steep climbs (AdZ, Radio Tower) much harder since I was grinding away at 50-60rpm instead of spinning at a higher rpm. Yes watts are watts but when you add in cadence they can become different watts.

Okay, cheers. In fairness, on that particular climb I averaged around 75 rpm to get my required wattage for such a long time, and both friends with smart trainers also averaged between 70 and 75. So I guess it depends

Definitely depends. The trainer difficulty selector on smart trainers will have a big impact as well. At 50% (the default setting) you can keep the rpms up, at 100% (I find) that’s when keeping up the rpms gets a lot harder. Cheers.

Yeah it’s a slight advantage but only on the steepest sections. When i moved to the Tacx Neo with Trainer difficulty set at 100% I can longer maintain my optimal cadence above 10% gradients.

Maybe that’s made me push harder on sections but it means I am less efficient overall

This is a really interesting question actually, and yes, it definitely depends!

In theory it should be a slight advantage to be able to have a consistently lower resistance and thus to be able to select your cadence, but in practice I find it easier to sustain FTP-level power over longer time periods if I’m going up a simulated hill with resistance of around 5 - 10%.

So, I find a 40 min virtual climb at my FTP power is about as hard as 2x20 mins at FTP on the flat (e.g. in a Zwift workout), and definitely easier than a 40 min FTP session on the flat… That’s provided that the gradient of the simulated hill is relatively constant - unfortunately Zwift doesn’t really have any hills like this, so I usually use something like BigRingVR and Col du Telegraphe or whatever.

I’m not quite sure why this is, but suspect it’s down to a combination of factors. On a simulated hill with signifciant resistance I will alternate between sitting and standing, and I believe this enables me to sustain a slightly higher average power by alternating the use of different muscle groups. In theory you could do this on the flat just by going into really big gears, but in practice, you don’t…

So I wonder if there is a big psychological element at work - the simulation of the hill is good enough to allow you to switch into a learned pattern of behaviour that is familiar and practiced from riding real hills out of doors. There may also be an element of self-image at work - I percieve myself more as a climber than a rouleur, so perhaps I’m able to push harder on hills than someone who is not a good climber and is intimidated by them.

However - as soon as the gradient of a simulated hill becomes quite variable, there comes a point at which this is disadvantageous because you lose power overall by continually having to adapt to changes in gradient / resistance. So, I can’t quite sustain my FTP up Alpe du Zwift for 50 mins, despite being able to do it on other simulated hills of similar duration.

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