long delay/lag in displayed speed

[wizardofaz]

I'm using a Bonrager Interchange Combo Sensor (s/c). The displayed speed and cadence on my Garmin 910XT is perfect. But in VeloReality VRide the cadence is good but speed changes lag behind realtime by a lot, 10-15 seconds. This of course makes the vpower also lag the same amount. Any thoughts?

[admin]

Speed reported by V-Ride software has no relation to your wheel speed. It is determined from the input power, your weight, road grade and whole bunch of other parameters. While you can increase speed of your bike's wheel almost instantly, it translates speed increase to increase in power (I assume you are using simple resistance trainer, alternatively the software takes power directly reported by either power meter or smart trainer). This in turn leads to certain acceleration which in turn leads to increase of speed. Of course it takes time to gain the speed (basic laws of physics do apply).

[wizardofaz]

Great, thanks. That's a more interesting answer than I expected. Implied in the response, I suppose, is an assumption that accelerating the flywheel through the fluid resistance provided by the trainer (Kurt Kinetic Road Machine) does not very well model accelerating the bike and rider through air during a road ride. The 10+ seconds seems excessive but maybe it's not. Sometime I'll trying to compare the acceleration data from a road ride to a trainer ride and see.
Thanks for the reply.

[admin]

...The 10+ seconds seems excessive but maybe it's not. Sometime I'll trying to compare the acceleration data from a road ride to a trainer ride and see...

Just do not forget to select proper power vs speed curve in setup if you did not do so already. If not the explanation is in Chapter 6 of the User's guide at : http://www.veloreality.com/exs_v_ride/v ... l_v1.0.pdf