Concept2 Forum

I've noticed lately that my DF is not remaining consistent. If I set it to my preferred DF of 125, it will change by itself to a higher or lower value in a day or so. I set it recently at 125 and noticed on a row I logged using the Ergdata a couple of days later that the DF was 129.

I realise that as dust accumulates in the fan on an erg this will lower the DF over time, but I'm not sure why it would increase the DF for no apparent reason.

Is this normal, or there something wrong with my erg? For me to get a DF or 125, my lever is always set to 4.5, which hasn't changed until these recent anomalies.

Funnily enough, I quite liked the feel of 129, which I would have thought was a bit high for a LWT rower. Not sure I'd want to do a long row at that though.

Temperature and atmospheric pressure also affect air density.

Just re-set the DF to whatever you want before every session. Or you can ignore the small variations due to changes in local conditions.

(I do the former, it just takes a few seconds.)

My df has been varying quite a bit recently, and I've seen 119 and 123 without touching it.

Ombrax wrote: ↑

October 23rd, 2023, 11:29 pm

Temperature and atmospheric pressure also affect air density.

Just re-set the DF to whatever you want before every session. Or you can ignore the small variations due to changes in local conditions.

(I do the former, it just takes a few seconds.)

Spring in Melbourne Australia is the most variable season we have, so that would explain it.

Good idea, it's super easy to check it before each session if an exact value is required. I don't use the Ergdata app regularly, so it's probably been changing all the time for months, I just haven't noticed it.

Dangerscouse wrote: ↑

October 24th, 2023, 12:43 am

My df has been varying quite a bit recently, and I've seen 119 and 123 without touching it.

Yeah, autumn/spring with strong variations in weather and athmospheric pressure tends to do that. My DF varied between 124 and 127 last week.

I simultanuously use a PM5 and OpenRowingMonitor, both exhibit the same behaviour. As I made and understand (and can even check) the drag calculation from ORM, it is the physical conditions that changed, not a monitor error.

Mine fluctuates by that sort of amount a lot - it did drop by 10 so got the hoover out for the cage and it went right back to normal range again.

opening the windows next to my erg also makes a difference too

p_b82 wrote: ↑

October 24th, 2023, 4:34 am

Mine fluctuates by that sort of amount a lot - it did drop by 10 so got the hoover out for the cage and it went right back to normal range again.

opening the windows next to my erg also makes a difference too

Actually, I have been opening the garage door sometimes, which is probably creating a lot more air flow.

Silly question, but can you hoover the cage without taking it apart?

robhely wrote: ↑

October 24th, 2023, 6:20 am

Actually, I have been opening the garage door sometimes, which is probably creating a lot more air flow.

Silly question, but can you hoover the cage without taking it apart?

I use one of the soft furnishing attachments with the brush, and just do the outside - it seems to be working so far, but if/when that stops being as effective then I'll take the cage off - but not needed to so far.

Mine has been fluctuating quite a bit as well, too, 5-10 points per day, with one day spiking up to 165, and another day ErgData recording no value whatsoever.

I noticed my drag factor changed (up from 110 to 120ish) when I got the giant fan to point at me during workouts.

These changes are quite significant, I would never intentionally set my DF 10 units higher or lower than my preferred setting.

I guess this is just a reminder to set the DF before every session, as mentioned above.

I think temperature is the usual reason for the variation.

Personally I always check the DF before rowing as I use a C-Breeze and if this slips it makes a huge difference.