Anyone know why this doesn't exist?

[emar]

Hi everyone,

Why isn't there an aftermarket device to attach to the flywheel for automatically adjusting the drag factor (or is there one and I just don't know about it?)? I know C2 prioritizes simplicity of maintenance, so I totally understand why C2 doesn't produce one (or come standard), but why hasn't anyone else made one? It seems like it'd be a perfect match for both the BikeErg and the SkiErg (probably also the RowErg, but rowing up and down a mountain doesn't seem as apt). It also seems like it'd integrate fantastically with Zwift and Krew.

Anyone have any engineering buddies and/or IoT tinkerers looking for a project?

[Citroen]

Why isn't there an aftermarket device to attach to the flywheel for automatically adjusting the drag factor (or is there one and I just don't know about it?)?

There is one. It's a homo sapiens with a pair of eyes on the monitor and a hand on the damper lever.

[Ombrax]

Because it would be somewhat complicated and a big increase in the price of the erg.

[Tsnor]

Hi,

What would you gain from dynamically adjusting the drag factor?

You change the power output of an erg by pulling harder, not by switching the drag factor, so switching the drag factor is not like changing the resistance (power) of a bicycle trainer.

re: "It also seems like it'd integrate fantastically with Zwift and Krew." - This is not what drag factor does. The wattage from the PM5 integrates with zwift, etc. The DF says nothing about how hard you are working or how hard you should be working. Imagine a zwift race where it only monitored what bike gear you were in, not how much power you were making.


(FWIW I do a mix of high speed intervals and long/slow, and I haven't changed my DF in over a year. I don't know what criteria I'd use to dynamically change the DF.)

[JaapvanE]

Because it would be somewhat complicated and a big increase in the price of the erg.

It depends how you make it. Nordictrack has such an option, which they achieve by adding a magnet into the drag-mix. By changing the magnet's position or its strength, you can change the flywheel's drag. As I understood, they integrated it with their iFit service.

But I must say, it isn't a nice type of drag. Where air resistance increases with flywheel speed (thus allowing you to work harder by pulling harder), magnetic drag's force is constant. So the catch can have a huge magnetic counterforce, disrupting the smooth flow you have with air resistance. It also makes drag calculations messy at best (as the mix of forces changes with the speed) and to achieve measureable effect you need quite strong magnets. To balance such magnetic resistance with air resistance, you need much more air resistance as well. Thus the NordicTracks have two flywheels. To give an idea: with OpenRowingMonitor I measured the drag of a NordicTrack RX800, which at its maximum reaches 450 (almost twice the drag of a Concept2). That is an insane level of drag, especially when you realise that 230 is already considered dangerous by Concept2.

[JaapvanE]

(FWIW I do a mix of high speed intervals and long/slow, and I haven't changed my DF in over a year. I don't know what criteria I'd use to dynamically change the DF.)

I typically row shorter rows with df 130-135 and longer rows with df 115-120. But like you said, it isn't a resistance, but more like a bike gear and the resulting pace/speed is what really counts.

[Ombrax]

It depends how you make it. Nordictrack has such an option, which they achieve by adding a magnet into the drag-mix. By changing the magnet's position or its strength, you can change the flywheel's drag. As I understood, they integrated it with their iFit service.

I agree that anything you do manually would be pretty simple, but when the OP said "automatically adjusting the DF" I assumed that s/he meant something electronic, where you would punch in the desired DF in the PM and an actuator of some sort would move something (damper lever, magnet gap, etc) to change the drag, and therefore it would be a non-trivial impact on cost and reliability.

IMO it's a minor issue that on a C2 row erg one can't easily change the drag while in the normal seated position, with your feet on the footplates (although I have seen at least one person use the handle to extend his reach and tap the damper lever) to do just that, but personally I tend to be a bit of a Luddite, so I'm happy with the system as currently implemented.

[Carl Watts]

Weird request and not required.

All you need to do is monitor the DF, its pretty much a set and forget otherwise, maybe change it for 100m or 500m sprints but otherwise you hardly ever touch it apart from a trim now and again as it drops over time due to dust build up.

Uploading your results using ErgData to the Concept 2 logbook reminds you if it needs adjusting, it logs the DF for every row.

[JaapvanE]

I agree that anything you do manually would be pretty simple, but when the OP said "automatically adjusting the DF" I assumed that s/he meant something electronic, where you would punch in the desired DF in the PM and an actuator of some sort would move something (damper lever, magnet gap, etc) to change the drag, and therefore it would be a non-trivial impact on cost and reliability.

As I read the OP, he wants to do something similar to several bike simulators, where Zwift will control the resistance of the bike, simulating uphill or downhill biking/skiing. So you change the drag dynamically to the terrain simulated by the bikeErg or skiErg. I can see some scenario's there, especially with Zwift in mind.

However, that would require some modification somehow: you want an actuator to change resistance. In all honesty, here the PM5 works against what people want to achieve: the PM5 treats a higher drag as a bike gear and thus the same energy always gets translated to the same speed. That is not what you want when introducing resistence on a bike to simulate an uphill ride, you have to work harder for less speed.

[Carl Watts]

You will find that for ranking a row you are not allowed to change the drag factor during the row.

While it may be a cool feature for those just playing on the Erg, its just not required.

You just don't need to be able to change the DF on the fly during the row, just pull harder or softer.

The Erg integrates poorly into the likes of Zwift anyway because the power conversion is far more complex than a linear function.

You simply do not need to change the DF to get an "Easy" or a "Hard" workout, its just all about the pace.

[Ombrax]

However, that would require some modification somehow: you want an actuator to change resistance. In all honesty, here the PM5 works against what people want to achieve: the PM5 treats a higher drag as a bike gear and thus the same energy always gets translated to the same speed. That is not what you want when introducing resistence on a bike to simulate an uphill ride, you have to work harder for less speed.

On a RowErg the PM and the drag simulate OTW rowing, and on the water there are no hills. Drag on the boat is drag on the boat. If you want to go faster you put more energy into the flywheel, either by pushing/pulling harder or more frequent strokes. If people want hills, then they should get something that simulates a bike. That isn't the purpose of a row erg. (I can't speak to how the Bike Erg works, I've never used one.)

[JaapvanE]

If people want hills, then they should get something that simulates a bike. That isn't the purpose of a row erg. (I can't speak to how the Bike Erg works, I've never used one.)

Hence the following sentence in th OP:

It seems like it'd be a perfect match for both the BikeErg and the SkiErg (probably also the RowErg, but rowing up and down a mountain doesn't seem as apt). It also seems like it'd integrate fantastically with Zwift and Krew.

[Dutch]

I think concepts whole view point is to create a simple fitness machines and stay away from technical.

Some people have taped a long stick to the bike erg to change mid way through a ride.

[Carl Watts]

Its not like the DF stays the same for your whole life.

I remember when I started out, everything was done at a DF of 168 and higher ratings of 27-28spm.

Fast forward 15 years and the drag has drifted down to 124 and ratings these days are typically all sub 20spm for training rows.

I no longer really "Race", longer distances were never really that good for me it was always 5K and below for my better rows.

Point is the DF is not super critical, it works between a range of probably +/-5 for the same result, its not like if it drifts out a couple of points you suddenly crash and burn.

[JaapvanE]

Point is the DF is not super critical, it works between a range of probably +/-5 for the same result, its not like if it drifts out a couple of points you suddenly crash and burn.

For me, I even get similar results for DF 225 versus DF 125. I know my arms won't take a 225 more than once a week, it is a totally different row from a HR perspective (much more an anearobic row) and I hate it, but theoretically I can do both for rowing. But I have no clue how it behaves on a SkiErg or BikeErg as the OP asks....