Cadence, Power and Speed


(Mike Simms) #1

Hi all,

I’m looking for some help. I run a Tacx Neo on Zwift, all paired sucessfully.

I rode a lap of London last night, trying to keep a relatively constant cadence (measured by Zwift).

Even when running a constant gear, I notice a big change in speed when going up or down hill.

Of course the wattage is changing depending on the incline.

BUT shouldn’t it be the case that if I push the same gear at the same cadence on flat or uphill, the speed should be constant?

Is there a reason for this (like I need to calibrate or change settings, etc)?

Or is the cadence measure on Zwift only estimated?

I would appreciate all comments. Thanks 


(Jon Mayfield) #2

I’m not sure if this answers what you’re asking, but your in-game speed is dependant on the how much power (watts) you put out, the virtual terrain, drafting, and how aerodynamic your virtual bike is.

If you were pedaling in a certain gear at 90rpm down a mountain, you might go 80kph.  If you were in that same gear at the same 90rpm going up the mountain, you might be at 10kph.

Your power goes into the physics simulation, and out comes a speed and acceleration.


(Stef Levolger) #3

In addition to what Jon already stated, do not forget the downhill simulation the Neo offers. At 0 watts the Neo itself will actually generate forward motion for you there, simulating gravity. Any wattage you give to this, is additive. Just like on the road.


(Mike Simms) #4

Thanks guys.

I hear what you say about downhill…

But flat or slight incline surely that isn’t a factor and 1 pedal revolution should travel the same distance (real or virtual).

Irrespective of power / wattage / how hard I push on the pedals 

Drafting also wasn’t a factor and I didn’t change my bike mid ride! :wink:

Any other thoughts anyone?

Thanks.


(Mark Hewitt) #5

All Zwift cares about is your power output - as measured by the Neo. Nothing else.

If you keep a constant power output you’ll go a constant speed on the flat. But only if your power output is constant.