Drag Factor readings

[MrGoodtimes75]

I just received delivery of a well-used Model D/PM3 from a refurber/reseller. I'm new to Erg life and followed lots of online guidance to make all the sensible checks. The only issue with it seems to be drag factor.

Moving through the damper settings, the range I'm getting is 70-145ish. Everything I read online suggests this should be more like 80-220. I can't see any good reason for it. The whole machine is extremely clean inside and out, it operates smoothly and has the following replacement parts:

New chain
New 17mm axel bearing
New flywheel bearings
New sprocket
New clutch

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!

[Citroen]

What elevation are you at? That has an effect on drag factor.

[Sakly]

What elevation are you at? That has an effect on drag factor.

I live close to sea level

I would suggest to clean the cage. Not only vacuum the outside, pull out the whole grid and clean it from both sides. This could help very likely.

[mict450]

Your upper DF seems very low. I'm at 3200 feet & my DF range is 60 - 200. Sakly's advice is good, especially cleaning out the perforated screen. I'm not real familiar with the PM3, but check out "Utilities" & make sure it's set for the model D. If that doesn't do it, I'd invest in a new PM5.

[mict450]

Oh, and welcome to the campfire.

[Ombrax]

Moving through the damper settings, the range I'm getting is 70-145ish.

By all means, check to see if the erg fan area needs a cleaning, but for the record, I bet the majority of the folks on this forum (but necessarily all) use a DF that falls well withing in that range.

Unless you're 6' 4" tall, a muscular 250 lbs, and you really have your heart set on doing 500m sprints, DF = 100-140 is plenty. Sure there are some "normal sized" knowledgeable and experienced rowers who do like to "set it at 11," but they are in a clear minority.

Bottom line, being able to "only" go to a max DF of 145 not necessarily a reason to go through the trouble of returning an erg, especially if it's a hassle or involves shipping.

[Carl Watts]

The holes in the flywheel screen are blocked or partially blocked.

Doesn't take much for the screen to make a big difference on airflow.

Take the screen off the rower and reassemble the side cover without the screen and row and report back with the numbers.

If the top end DF shoots up to like 250, then its obviously the screen.

[Dangerscouse]

Moving through the damper settings, the range I'm getting is 70-145ish.

By all means, check to see if the erg fan area needs a cleaning, but for the record, I bet the majority of the folks on this forum (but necessarily all) use a DF that falls well withing in that range.

Unless you're 6' 4" tall, a muscular 250 lbs, and you really have your heart set on doing 500m sprints, DF = 100-140 is plenty. Sure there are some "normal sized" knowledgeable and experienced rowers who do like to "set it at 11," but they are in a clear minority.

Bottom line, being able to "only" go to a max DF of 145 not necessarily a reason to go through the trouble of returning an erg, especially if it's a hassle or involves shipping.

Good point. I hardly ever set it above 145, and I'm settled on circa 125ish for almost everything.

[jamesg]

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.

It's easy to reduce drag, and there are plenty of ways to do it. I use a filter over the air inlet and like to think I can still do some work at df 85-90. Lets me move quickly even at low force level, 350N and rates 20-22 (ergdata); and keeps the fan clean.

I would have thought a D would have a PM5, not a PM3; maybe there's a difference in calculations, so could try an update or switch to a 5. (just guessing)

[JaapvanE]

I would have thought a D would have a PM5, not a PM3; maybe there's a difference in calculations, so could try an update or switch to a 5. (just guessing)

Older D's came with a PM3 (my gym had two of them). The results of the algorithm for drag remains pretty stable acriss PM's, as it is basic physics and we do the same with OpenRowingMonitor (and we validate our results against a PM5). The flywheel is a tiny bit different with the new 12 pole magnet construction instead of the 3 magnets, influencing inertia and drag behaviour a tiny bit, but results should stay the same.

[MrGoodtimes75]

check out "Utilities" & make sure it's set for the model D. If that doesn't do it, I'd invest in a new PM5.

Thanks for this, I'll try it - the seller has offered me a brand new PM5 at half price, but for the extra money I could probably have bought a much younger machine in the first place.

[MrGoodtimes75]

The results of the algorithm for drag remains pretty stable acriss PM's, as it is basic physics

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?

[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.

[MrGoodtimes75]

Moving through the damper settings, the range I'm getting is 70-145ish.

By all means, check to see if the erg fan area needs a cleaning, but for the record, I bet the majority of the folks on this forum (but necessarily all) use a DF that falls well withing in that range.

Unless you're 6' 4" tall, a muscular 250 lbs, and you really have your heart set on doing 500m sprints, DF = 100-140 is plenty. Sure there are some "normal sized" knowledgeable and experienced rowers who do like to "set it at 11," but they are in a clear minority.

Bottom line, being able to "only" go to a max DF of 145 not necessarily a reason to go through the trouble of returning an erg, especially if it's a hassle or involves shipping.

I've been thinking the same, but since the readings are already different form what I was expecting, I have this niggling doubt that the numbers I'm getting don't reflect reality, in which case, I have no way of knowing what I'm pulling at all. (I might be over thnking things!

[MrGoodtimes75]

The holes in the flywheel screen are blocked or partially blocked.

Doesn't take much for the screen to make a big difference on airflow.

Take the screen off the rower and reassemble the side cover without the screen and row and report back with the numbers.

If the top end DF shoots up to like 250, then its obviously the screen.

Interesting possibility - I will try this when I'm checking the presence and condition of all the blades, but on visual inspection with a torch the perforated screen appears extremely clean (the whole machine appears to have been thoroughly cleaned by the seller)