Drag Factor readings

[MrGoodtimes75]

Oh, and welcome to the campfire.

Thanks! Glad to be here

[JaapvanE]

I'm no techy but that was my thinking - it's a live read and should be stable, unless there's something amiss with the magnets you mention, could that be?

In theory, yes. But then your pace should be way off, and the force curve would be a total mess....

[lindsayh]

I live close to sea level and the rower is set up in my garage where it is currently quite cold - all of which I've read should support normal drag. I have a 90-day warranty on the machine, but I don't want the inconvenience (and shipping cost) of returning it if it can be avoided.
I'd welcome any ideas or suggestions about what the issue could be, both mechanical and electronic.
Many thanks!

95% sure to be a dirty cage and really simple 10 minute job to take the perforated strip out and clean it and the fan. DF will be >200.

[MrGoodtimes75]

Nope, the machine was fully serviced and refurbished by the seller. Very clean everywhere.

[MrGoodtimes75]

Maybe too near a wall or some other obstacle, inlet side.

The air outlet has to be completely free too and the fan have all its blades.

Interesting! It is currently positioned with the inlet facing a wall close by. I will move it and check again! As for the blades, i will open it up and check. So far I've only inspected with a light through the grille and the perforated panel. That's enough to see it's very clean inside, much harder to check for missing blades. That said, the seller seems pretty thorough on the refurb, so I'll be surprised if he missed that! Thanks.

@jamesg - you win! The inlet had around 30-40cm clearance from the adjacent wall, so I wasn't hopeful, but when I tripled that distance the DF jumped to exactly where it should be. Great tip! Thanks

[MrGoodtimes75]

@jamesg wins! The low DF was down to the rower being too close to a wall. It had around 30-40cm clearance, so I wasn't hopeful, but when I tripled that distance the DF jumped to instantly to where it should be. Very happy - that was the easiest possible solution

[Sakly]

Perfect!
Happy rowing

[MPx]

The low DF was down to the rower being too close to a wall.

I'm very pleased for you, but surprised. Maybe you are talking about the right side of the cage (?) as that is open in my setup. But the end of my erg is only 9cm from the wall, left side 75cm, and I get >200 on 10.

[MrGoodtimes75]

The low DF was down to the rower being too close to a wall.

I'm very pleased for you, but surprised. Maybe you are talking about the right side of the cage (?) as that is open in my setup. But the end of my erg is only 9cm from the wall, left side 75cm, and I get >200 on 10.

Yes, that's right, it was positioned with the grille on the right side about 30-40cm from a wall.

[hikeplusrow]

The low DF was down to the rower being too close to a wall.

I'm very pleased for you, but surprised. Maybe you are talking about the right side of the cage (?) as that is open in my setup. But the end of my erg is only 9cm from the wall, left side 75cm, and I get >200 on 10.

Yes, that's right, it was positioned with the grille on the right side about 30-40cm from a wall.

I've often wondered what the parameters are with regard to this (as you do!). Do C2 have any recommendations as to how how far from a solid surface the cage needs to be?

[MikeBuso]

I thought this would be a reasonable place to share some recent research I did on my own Model D/PM5. That rower was new in October 2020 when I replaced my Model B/PM5. That PM5 replaced the PM (1) that came on the Model B when I bought it used in 2003.

My drag factors in standard configuration range from 78 to 213.
With cage removed (open fan) drag factor was 208.
With the cage back on but no screen, range was 99 to 333.
With the screen on but mostly blocked with tape range was 46 to 56.

With this in mind, anyone could make minor adjustment to have their drag range from 45 to 333.
We know there can be variations among machines and depend on machine cleanliness.

Obviously, you wouldn't want to go without a screen completely if there was the possibility of fingers or other objects entering the fan. Other modifications to decrease the resistance from the screen could be done if you wanted to safely increase the drag above the standard range.

[Enda777]

Shock cord replacement will sort out the drag factor. You have mentioned chain and everything else apart from this. I replaced mine and the drag factor returned to where it should be at....Damper 5 (high) = 130 with new chord. Damper 5 (high) = 112 with old chord.

Reason would be loss of elasticity over time (of the shock cord).

[JaapvanE]

Shock cord replacement will sort out the drag factor.

No, it will not. During the recovery, when drag is measured, the flywheel is even disconnected from the chain, sprocket and shock-cord. as they move in opposite directions

[Ombrax]

I have to agree with this ^^^^ I don't see any logical the bungee cord stiffness can have a measurable effect on the DF.

Was it just a coincidence? Perhaps during the process of changing the bungee some other variable changed that did affect the DF.

[jamesg]

Great tip!

All praise to Occam's razor.