Setting drag factor

Discuss all things related to the BikeErg, Concept2's newest product.
VivaTerlingua
Paddler
Posts: 10
Joined: September 27th, 2017, 6:48 pm

Re: Setting drag factor

Post by VivaTerlingua » June 19th, 2018, 4:11 pm

So could somebody do a recalibration with the drag on high then cover the opening and break all the bikeerg records?

CaseyClarke
500m Poster
Posts: 78
Joined: July 1st, 2016, 8:59 am

Re: Setting drag factor

Post by CaseyClarke » June 20th, 2018, 4:10 am

VivaTerlingua wrote:So could somebody do a recalibration with the drag on high then cover the opening and break all the bikeerg records?
Pretty sure I’ve already seen a case where this happened in the Facebook BikeErg group, although they never admitted to it. Either that or they calibrated first, set it to high drag, then wrap a towel around the flywheel. I think in this case it still detects the same high drag, but the pedalling resistance becomes much lighter.

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johnlvs2run
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Re: Setting drag factor

Post by johnlvs2run » December 28th, 2018, 10:49 pm

c2jonw wrote:
June 15th, 2018, 8:33 am
The BikeErg doesn't have a significant rundown period and must be manually calibrated. Once calibrated there are three inputs that the PM uses to calculate the current drag factor- damper position via an angle sensor, temperature and barometric pressure. As these inputs change the PM revises the drag factor. This method will not detect a change in drag factor from restricting the airflow by any means other than moving the damper. So while you can achieve very light loading by blocking the airflow, your scores will not be accurate. C2JonW
From a check of various logs, the pace is directly proportional to the RPM for each specific drag setting.
Thus regardless of the drag setting, the fan speed is directly proportional to the RPM, although the average is not shown in tenths.

If that is correct, I did find instances in logs were the RPM for a drag setting resulted in an out of proportion much faster pace,
which based on previous posts, could indicate that the intake was blocked, perhaps unintentionally, as this seems to be easy to do.

I wonder why C2 didn't implement a more accurate way to measure the air flow resistance, and to compare it with the fan speed or cadence.
72, 5'8", 155lbs
Let's develop a pace (watts) per weight ranking system.
my training log

CaseyClarke
500m Poster
Posts: 78
Joined: July 1st, 2016, 8:59 am

Re: Setting drag factor

Post by CaseyClarke » December 30th, 2018, 4:12 pm

All too easy to trick the outputs on these unfortunately. If you drape a towel over the flywheel it significantly reduces the pedaling resistance (to almost nothing) but the drag factor stays the same. Max drag with a towel covering the flywheel makes it super easy to get below 1:00 pace (2000w+) and could be sustained all day. Once you've 'pedaled to calibrate' right before a ranking distance, doing this doesn't affect the verification code. Ranking scores can easily be cheated. As much as I'd like to see BikeErg records, I hope they are only a thing for venue competitions.

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