PM3 Accuracy?

[barneyrussel]

Hi all,
Apologies if this is the wrong section, does anyone know how accurate a 2021 PM3 monitor is please? i'm 5ft 6in, fairly stocky, not weak, with a short inside leg measurement and overweight which i know affects overall stroke length/watt generation etc and i can only generate around 80 watts average on a one hour row (i can max around 120 watts for a minute or so) i have rowed over a million metres on my 2021 model d that i bought last year and the max distance i have managed is 10850 metres in an hour starting at around 26 spm and ending at around 32-34 spm which apparently isn't too bad but everywhere i read it says i should easily be pulling around 150-200 watts, my form isn't too bad but the only other rower i know is around 5ft 9in and he easily seems to be able to pull 180 watts, i'm not too worried as i get a good workout but it would be nice if i knew whether it was reading under or not,
Thanks.

[Citroen]

The PM2, PM3, PM4 and PM5 are all fairly consistently accurate and there is very little variation between a PM2 from 1995 and a PM5 from 2025.

The thing that makes one PM2/3/4/5 feel different to another is how much crud and cruft is in the fan cage. If you block the fan cage you will reduce the drag factor and that makes your rowing experience very different.

The PM2/3/4/5 can all read drag factor. On a clean machine with the damper lever at 10 you should get a drag factor of around 200, with the lever on 1 it should be about 90. So, it may be time to open your flywheel cage and clean out the dust bunnies. Then set the drag to around 120-130 and see what that gets you for your rowing performance.

https://www.concept2.com/training/artic ... er-setting

If it's not a fan cage that's full of dust then it will be a technique issue. Rowing is a sport done with your legs (pushing away), it is NOT a sport done by hauling anchor with your arms and upper body. There's some good videos on YT that show how to resolve your technique issues.

[gvcormac]

The PM3/4/5 are true ergometers in that they measure power (watts) delivered to the flywheel, independent of drag factor, stroke rate, or anything else.

If you want to increase power there are three ways: pull harder, use a longer stroke, or use a higher stroke rate.

Drag factor has only a second-order effect: If you pull for the same distance with the same force, your stroke will take more time with a higher drag factor. This will give you less time for recovery (at the same stroke rate). So it makes sense to make your drag factor low, so long as you are able to generate the same amount of force.

ErgData can be configured to show all of these things as you row. Unfortunately, on PM3 you need a now discontinued version of ErgData (and a printer cable) as the newest version only works with Bluetooth, and only PM5 has Bluetooth.

If you don't want to rely on a discontinued app, I believe BoatCoach provides similar abilities, including uploading to log.concept2.com, which is useful to track progress.

Here are the Android versions (not sure about Apple).

Old ErgData: https://apkpure.com/ergdata-for-pm3-pm4 ... 4/versions

BoatCoach: https://play.google.com/store/apps/deta ... h&hl=en_CA

[barneyrussel]

Ok thanks, i have cleaned the fan cage out a couple of times so its probably not that and i have watched quite a few videos and think my form isn't too bad, i know the sequence of leg drive, body swing and arm pull, i did check the drag factor a while back but will check it again.

[barneyrussel]

@gvcormac

Thanks for the information, i will check tomorrow.

[Tsnor]

does anyone know how accurate a 2021 PM3 monitor is please?

not sure what you meant by 2021 pm3 monitor.

At the risk of trusting chatGPT, "no new PM3s have been built since 2014; the factory switched the production line over to the PM5 that year."

PM3 (and PM5 which would be the 2021 monitor) needs to be configured for correct rower type. If the monitor is misconfigured it will report the wrong split.

Here is how you configure a PM3: https://www.concept2.com/support/monito ... leshooting in the STUCK ON ZERO section:

On the Main Menu, choose More Options.
Choose Utilities.
Choose Product ID. Look at what appears next to "Model." This should be D or D/E for Model Ds, and D/E for Model Es and Dynamic Indoor Rowers (for reference, D/E will also be listed for SkiErgs, but this procedure applies to indoor rowers only). If you have retrofitted a monitor to an older indoor rower, this should read C, B or A according to the indoor rower you have. If this doesn't match the indoor rower model you have, take the following steps:
From the Main Menu, select More Options > Utilities > LCD Contrast.
Press Change Units or Units three times.
Press Change Display or Display three times.
When the Set Rower Type screen appears, press the button next to Change Type until the correct indoor model is displayed:
D or D/E for Model D Indoor Rowers
D/E for Model E and Dynamic Indoor Rowers
C, B or A as appropriate for the indoor rower you have, if you've retrofitted a monitor to an older machine
Select Set Type to save the setting.

[barneyrussel]

I just meant that's how old the rower is, its the late July 2012- April 2021 model d with a 2021 serial code, i bought it last year having covered 42k metres and was already configured by the previous owner.

[jamesg]

A 5'6 Male (1.7m) with "fit" weight 23-1.7² = say 65kg might be able to pull a stroke of length 1m at average force around 300N, according to age and health. Which stroke is worth 300Nm.

Pulling 20 such strokes per minute implies a Power of 300 * 20/60 = 100 Watts. Which more or less is what you are doing. You can see your numbers in Ergdata.

Basic technique on the erg as shown by C2 requires us to get to a strong but relaxed posture at the catch and then slam the legs down as hard and fast as possible. This is essential on C2 ergs because we have to catch up with the spinning flywheel. Keep your forearms, wrists and hands flat and straight at the finish, to avoid injury. Using the legs and hips, as you will notice if you climb stairs, provides plenty of physical stress.

Suggest you use the C2 Wods, available here https://www.concept2.com/training/wod which are a lot shorter than an hour. I find them very effective fitnesswise, doing them all with little prior warmup (5' max) but the last 20% as fast as possible. Which is my version of the famous 80-20 mantra, satisfying it every day.

[barneyrussel]

Ok thanks, i will have a look a bit later.

[p_b82]

not sure if the pm3 displays the force curve, but if yes what's the shape of yours with each stroke?

It won't have a high amplitude but c2 link it should be along the lines found here.

If you've got a very shallow start and steeper at the end, you're pulling (arms) not pushing (legs/back) & it is a technique issue.

[JaapvanE]

not sure if the pm3 displays the force curve, but if yes what's the shape of yours with each stroke?

PM3's have a force curve, but it is a bit less accurate with the older sensor setup (3 magnets and a small coil) as it only provides 3 signals per rotation instead of the current 6/infinite. Don't know when they switched to the new sensor setup.

[gvcormac]

not sure if the pm3 displays the force curve, but if yes what's the shape of yours with each stroke?

PM3's have a force curve, but it is a bit less accurate with the older sensor setup (3 magnets and a small coil) as it only provides 3 signals per rotation instead of the current 6/infinite. Don't know when they switched to the new sensor setup.

I'm confused. Did the sensors change mid-production of the Model D, when it was fitted with a PM5? Or are you referring to the Model C, which had a different pickup?

[JaapvanE]

I'm confused. Did the sensors change mid-production of the Model D, when it was fitted with a PM5? Or are you referring to the Model C, which had a different pickup?

That is the thing, I can't find when they changed the pickup sensor. C2 has a habit of changing stuff mid-production. For OpenRowingMonitor I supported both retrofits on Model C's with a PM3 and retofits on Model D's with a PM3, and in between there C2 has switched pickup sensor and thus flywheel construction. It would make sense to do this when switching model name from model C to D, but I wouldn't bet the house on it, especially with C2.

[gvcormac]

C2 appears to have switched from "generator assembly" (PN 1887) in the 1st gen Model D (PM3), to "sensor coil" (PN 2401) in all subsequent Model Ds (which were delivered with PM3 or PM4 or PM5). https://www.concept2.com/support/indoor ... schematics

Model C, on the other hand, had "monitor sensor" (PN 1748) (PM2 or PM3). https://cms.concept2.com/sites/default/ ... cParts.pdf

[barneyrussel]

The last time i checked which was quite a long time ago it was a bit pathetic, like a small mound, i will need to check again, its certainly looking like a form issue then although i thought mine wasn't bad, i watched quite a few videos from the likes of rowing tall and dark horse rowing.