Are old, used ergs faster?

cars · Post by **cars** » August 14th, 2006, 1:41 pm

Howdie, here is one for the technical wizards:
I hav bought a new Model D at a race in April this year where my rowing club also picked up a new Model D.
Where I have put 400,000 k on it and kept it nice, the Model D in the club has been used by everybody and has already suffered, looks battered. The k's rowed on that thing I cannot determine.
Recently I did a 6 k piece on it. I had to put the damper on 8 to make it feel like on damper 2 at home. Rowing went rather easy. My 6 k was good, but not widely off what I could expect, but still...
Now my questions:
Does the old, battered erg give the same results concerning /500m times compared to the new one? Therefore, are old, used ergs faster?
Is the higher damper setting the equivalent to reaching the same SPM in a "worn-out"machine as compared to a newer, "sharper"one?
Thanks, regards, Cars

tomhz · Post by **tomhz** » August 14th, 2006, 2:22 pm

Cars,

I copied this from a FAQ thread:

3. Resistance level -- Drag factor

The resistance you experience comes from the acceleration of air by means of the fan in the circular housing at the front end of the erg. The leaver on the side of the fan opens or closes the fan (resistance level setting). The more air you let in the more air you have to accelerate and the more resistance you will experience. How much air gets accelerated depends on how far the fan intake is opened (resistance level setting) but also on the condition of the machine (dust in the fan intake and on the fan blades).

Consequently the same level setting on different machines can lead to different actual resistance levels. To account for these differences we have the so called drag factor, a normalized measure of the actual resistance. Equal drag factor on different machines means equal resistance. The erg can measure and display the drag factor. To display the drag factor at any given resistance level setting proceed as follows:

PM2/PM2+ monitor: Clear the monitor (press Off/On twice). Now hold down both the "rest" and "OK" button. The word "drag" appears in the lower right corner of the monitor. Row for a while at 2:15 splits. The drag factor will be displayed in field labelled "drag".
PM3 monitor: Press "other options", then "display drag factor" and proceed as above.

Now move the resistance lever up and down (while rowing) and observe how the drag factor changes.

Which drag factor should you be using: 100 - 130 is a good setting for most but opinions on this differ. There is much discussion of the drag factor on this message board. My own preference is for the lower end of the range. Note that these settings correspond to low resistance settings on the erg. It is a common mistake for beginners to be on level 10.

So you need to start comparing Drag Factors, not damper setting.
Let us know if this helps.

Tom

cars · Post by **cars** » August 14th, 2006, 2:39 pm

1st a correction: it is 400,000 m and not km, of course.
Thanks for the answer. I know the difference between drag factor and damper setting and will control the drag with the two erg's mentioned.
But still: Is it technically possible that at the same drag factor an older, more used erg displays higher speed on a /500m base (or more work done if you like).
Do erg's have to be "redadjusted" at a certain age, mileage?
Can there be a bias in the times reported from all these Model B,C,D erg's all over the planet?

I am not an engineer, a simple yes/no with a short explanation from one of the known experts here does the trick.

EdTheRed · Post by **EdTheRed** » August 14th, 2006, 3:42 pm

I'll leave the technical explanations to someone better suited to them, but my understanding is that, aside from various factors that affect the drag factor over time, there are things like worn gear teeth, rusty chains, and loose shock cords that can affect an ergs performance insofar as they affect how hard it is to take a stroke...however, once the stroke is taken, I believe the PM is merely measuring how much power is being generated per stroke, and then converting that into various hypothetical "units," like calories and meters; that aspect shouldn't change.

If it felt easier to row on the beat-up model, it was likely because of the changes in the drag factor.

With regards to older models, however (leaving aside the Model A, since I haven't rowed on one since the late '80s), my personal experience is that the resistance on the Models C & D is more consistent throughout the stroke, while on the Model B, it was more "front-loaded," which is to say that there was more resistance in the first half of each stroke, and if you hit the first part of the drive hard, the second half of the stroke felt lighter. As a result, I approached pieces on the Model B a bit differently, going for a more explosive first part of the drive (closer to on-the-water rowing, really). On the C & D, I try to maintain a steady force through out the drive. The Model C was released when I was a college rower, and the heavyweights on the team (like myself) had an easier time adjusting to it than the lightweights, who lacked the mass to maintain momentum throughout the stroke.

Again, the same concept applies regarding the PM readings: all the PM does is record and convert how much power is generated with each stroke. The differences between machines merely affects what techniques are most efficient.

michaelb · Post by **michaelb** » August 14th, 2006, 3:45 pm

I believe they are supposed to be the same if the drag is the same. My guess would be that an older erg would be "slower" if only slightly, due to wear causing greater friction in various areas and less tension on the shock cord as it stretches, both resulting in some net loss of energy in the system.

PaulS · Post by **PaulS** » August 14th, 2006, 3:46 pm

Any model Erg, in good repair (no debris around the axel, no stiff chain or extra tight bungee), with a PM2 or above, will report the same pace for a given power input.

Even large variation in the flywheels Moment of inertia does not alter the expected Pace output in more than a very minor way.

neilb · Post by **neilb** » August 15th, 2006, 12:58 am

Only personal experience but older, well used, ergers are definitely much slower (not sure it is due to rust but lost/worn teeth sounds possible

Neil B.

holm188 · Post by **holm188** » August 15th, 2006, 2:30 am

Maybe some environmental factors influenced your performance:
is there better air circulation at the club than at home?
is the temperature similar? (I usually try to work out at max 23C, if the room gets up to 25 or more I can see a significant drop in performance, for timed pieces I try to get the room down to 18-20C)
Is the air humidity similar?
did you row alone at the club or were there others rowing on ergs besides you?

All that can affect the perception of the effort level.

Just a few thoughts...

cars · Post by **cars** » August 15th, 2006, 3:29 am

Great answers, thank you guys.
So technically there should not be a difference. Good to hear, because that leaves a nice PB unspoiled.
Psychology might be a factor. I normally train in my garage: just me, myself and I, good circulation and temperature, but not the most motivating surrounding.
At the club the erg's are in a big, rather dark hall, surrounded by all the boats. I rowed alone, but still: The smell, memories of old training days, an old club mate walking by occasionally with a quick glimpse at the display and an ironic remark. You guys know how that works...
At home it is just changing, hopping on the erg and go.
The rowing club means driving there, changing in the locker room. Just more procedure and mental preparation.
That might be it!
So I know where to go for PB's from now on!
Thanx everybody.

marathonoflife · Post by **marathonoflife** » August 15th, 2006, 11:16 am

find the old c2 at the YMCA has lower drag factors than what is supposed to be.

eg;

lever setting 10 = 184 drag factor after cleaned it (best I could,
have no permission to unscrew the side to clean the blades -which should be done, it's ugly in there)
and prior to cleaning 10=173

also find a difference in time between rowing with eyes closed vs open...closed=faster

perhaps touches on the 'environmental factors' sector of this discussion.