Rollers? speed data. First ride experience.


I used Zwift while on riding on rollers. I found that my speed displayed in Zwift was quite different from what my bike computer was showing. The speeds matched best at a 2% incline. My Zwift average was easily 4mph higher, and my Max speed was 14.3mph higher!

Jason K. from Zwift replied with this comment: “Speed in Zwift is calculated based on watts, so any other factors, such as speed, aren’t considered relevant in translating your performance into Zwift.”

I have a resistance drum, and my speed on the rollers is close to what I see when riding on the road.

Anyone else using rollers?

How well does the speed data match up while on a trainer, or exercise bike?

Overall Zwift worked great, and time flew by.

Thank you for any feedback you have,

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Speed on a trainer or rollers has no relevance at all to your speed on zwift. Watts go into our model to propel your virtual mass through our simulated world based on a standard rolling resistance, incline, and wind resistance model.

An extreme example could be somebody on rollers with very little resistance might be spinning at 50mph while going up our virtual 10% grade at 4mph in game.

I do understand that you may have your rollers set to match your particular real world speed, but Zwift has no idea what your real coeffecient of drag, frontal area, or what position your body is typically in so we pick a standardized model and go with that.

Does that make sense?

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Hi Steve,
I use rollers too. I have an old fixed set that I updated with Sportcrafters drums. I use 1 fluid resistance drum & 2 high inertia drums. I am super happy with this setup. I just did my first Zwift ride yesterday though and have lots of questions. Where can I go see my Zwift ride stats? I also tracked the ride on my Garmin Edge 500 so I should be able to compare too.

Thanks for the explanation Jon with Zwift.

@Joseph. Zwift saves your ride to a standard .fit file. For now you will need to upload it to your favorite site for analysis. They are saved in your documents folder. You should be able to copy and past this path into Windows Explorer:


@Joseph, did you add both drums at the same time, or did you get the OverDrive Drum first, and add the High Inertia Drum later? Are you able to coast with the High Inertia Drum? Did you sell your old drums already?

Hi Steve, I added a fluid resistance roller late last Winter, a high inertia drum about 3 weeks ago, and a second high inertia drum just this past week. (Competitive Cyclist had a 20% off sale) I am very happy with the spin down. I also have a neurological foot drop condition in my rt foot so I have very little strength pulling up & around the pedal stroke. The high inertia drums have been very helpful with that as well. I believe I have the two most recent old drums still but I may have thrown out the old one I replaced last Winter.

I had a similar experience last evening. This was (FINALLY) my first time using zwift despite being in the beta since before Christmas.

I spent a good 10 minutes trying to figure out why my speed wasn’t showing up despite the fact that I had my speed sensor paired properly. Then I finally figured out what was going on (calculating speed based on power and estimated mass).

My rollers are the old-school style–no resistance other than roller diameter (which is narrow). The only resistance unit is an old towel folded under the rearmost roller.

@Chris Welcome to Zwift. You will have a blast, it gets addicting. If you have more questions about the OverDrive, or High Iinertia drum let me know.

Steve, thanks for the welcome. I have a fluid trainer as well for resistance-based workouts. I picked rollers because I’m recovering from the flu (real flu not just a bad cold) and the rollers make it hard for me to go too hard whereas fluid trainer makes it hard for me to go easy.