BikeERG and Zwift distance discrepancies

[SMacK]

Hi,

Just picked up a new BikeERG recently and I'm seeing significant distance discrepancies between what is being reported in Zwift and on the PM5 (see examples below). I'm sure there are other Zwift/BikeERG users out there. Is this normal? Does everyone else have such significant discrepancies between the two, as I would have thought the two distances would be on par or at least closer.

A couple examples:

- a 65 minutes ride on the 13th that recorded 30.10km on Zwift and 26.32 km on the BIkeERG.
- a 55 minutes ride on the 14th that recorded 25.72m on Zwift and 22.88 km on the BIkeERG.

Thanks for any feedback/advice in advance.

Sarah

[UltraRow]

The bikeerg measures power, rather than speed and distance.

Both the distance displayed on the bikeerg monitor and the distance shown on zwift are derived from exactly the same power measurement. However, that power measurement is used very differently by each.

The bikeerg converts power to distance by a direct conversion, which is consistent for all bikeergs at any time, and independent from the rider. Zwift simulates a rider, based on their weight and height, the environment (hills, draft, rolling resistance), and the simulated bike being ridden. The bikeerg does not get feedback from zwift, so a discrepancy is to be expected.

[zij]

I've been using a Bikeerg with Zwift for the last 13-14 months and yes I see the same discrepancy as you.

Taking a flat route like Tempus Fugit, i find that the Zwift distance is about 10% more than the Bikeerg distance.. If I go on a hilly route then the Bikeerg distance can be twice the Zwift distance..

Zwift obviously logs everything you do, and syncs with Strava etc - but I just go off the Bikeerg distance when monitoring my training and comparing week to week or month to month..

[Carl Watts]

Its the power conversion in Zwift based on your height and weight you entered. It creates a profile for you that is quite complex and must even include your drag coefficient for drafting.

The BikeErg is way closer than using the Rower, basically I can HALF the Zwift distance to that what appears on the rower.

As above you would probably need a smart trainer to be able to see the same result on the bike monitor as what's in Zwift.