# Speed/Distance Data

I tried searching for an answer to this, but came up empty. Despite this, I suspect that this topic has been discussed at length, so if someone can point me to a relevant thread, I’d appreciate it.

I have a KICKR ROLLR. My bike is fitted with Garmin Rally pedals; they’re how the setup gets power and cadence data. I run SYSTM on my Intel Mac. Given these parameters, how does SYSTM figure out speed and distance? How well do these map to “real world” conditions?

My intuition tells me that the SYSTM values are more or less reasonable, but I may be wrong.

The following bikes are NOT COMPATIBLE with KICKR ROLLR:

• Any wheel size other than 700c

Given the above, I would assume that the ROLLR just measures the rpm of the roller and uses some average 700c wheel circumference (unless you can specify an actual wheel rollout length in the Wahoo App when setting up the ROLLR).

That’d be my assumption as well since it’s a pretty straightforward way to do it. I just wanted to get others’ take. Thanks!

If you’re using the built in Wahoo speed calculation - not sure what it’s called now, but it used to be “SUF speed” then I beleive it uses your power and weight to calculate speed which is aproximately what you would be doing in real world controlled conditions i.e a flat road with no wind.

Comparing total distance for a workout with RPE I think it’s about right and not overly optimistic in the way ZWIFT tends to be. That said I don’t care about speed or distance in Systm, the only metrics I have on screen during a session are heart rate, power and cadence.

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It’s called virtual speed.

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Ka-CHING! Thanks!