O&B calibration - variation

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Darkstar
Posts: 20
Joined: Mon Feb 06, 2017 7:58 pm

O&B calibration - variation

Post by Darkstar »

Long story short, I have done 2 O&B rides on the same bike, with the same everything - & have 2 somewhat different calibration results.
Same route, so apart from the wind I can't figure out where the difference comes from & whether one, both or neither is correct.

What am I missing??
1: Aero 0.781 Wind Scaling 2.301
2: Aero 0.675 Wind Scaling 1.989

The difference seems to be a difference of 15-25 watts (average) when tested against rides from last year which used a completely different profile to either of these (change of profile after the event). That's roughly a 10% error.
Attachments
iBike_2017_02_15_1614_4_Miles_CalRide.ibr
Second Calibration Ride
(73.19 KiB) Downloaded 266 times
iBike_2017_02_11_2035_3_Miles_CalRide.ibr
First calibration ride
(68.93 KiB) Downloaded 243 times
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: O&B calibration - variation

Post by Velocomp »

I would use the 2/11 cal ride. Ground wind was less.

Your 2/15 ride is higher watts because your bike speed was higher on the second cal ride. The difference in wind scaling is not significant.

I can't comment about comparisons to last year.
John Hamann
Darkstar
Posts: 20
Joined: Mon Feb 06, 2017 7:58 pm

Re: O&B calibration - variation

Post by Darkstar »

Thanks John. I'll redo things on a still day & run with that.

Incidentally, to avoid confusion for future readers - my mistake but this should have been in the Powerpod forum
Velocomp
Velocomp CEO
Posts: 7793
Joined: Fri Jan 11, 2008 8:43 am

Re: O&B calibration - variation

Post by Velocomp »

I moved your question to the PP forum.
John Hamann
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