Drag Factor Explained

On an air rower there are two things people conflate constantly, and keeping them apart is the difference between setting your machine correctly and guessing. One is the damper — the lever on the side of the flywheel housing. The other is the drag factor — a number the monitor calculates. They are related, but they are not the same, and the drag factor is the one that actually matters.

What the damper does

The damper controls how much air enters the flywheel housing on each stroke. Set it high and more air gets in, so the flywheel slows down faster between strokes and each pull feels heavier and more like lifting. Set it low and less air enters, the wheel keeps its speed, and the stroke feels lighter and quicker. We have a full guide to the damper here. The crucial thing the damper is notis a difficulty dial — damper 10 does not mean “hard mode.” It changes the character of the stroke, not how much work you have to do.

What the drag factor measures

The drag factor is the monitor’s measurement of how quickly the flywheel actually slows down between your strokes — the real-world result of the damper setting, the air temperature, the altitude, and how clean the flywheel screen is. On a Concept2 PM5 you can read it directly (it is in the monitor’s menu), and it typically lands somewhere around 90 to 140 for most rowers, depending on preference.

Here is why the distinction is not pedantry: damper 5 on a dusty flywheel in a hot room at altitude produces a completely different drag factor from damper 5 on a clean machine at sea level. The damper number is a rough input; the drag factor is the actual output. If you want to set your machine to a repeatable, comparable resistance, you set it by drag factor, not by the lever.

Why it matters for comparing and training

Two reasons. First, comparability: if you train on one Concept2 and race or test on another, matching the drag factor — not the damper number — is how you make the two machines feel the same. A coach who says “set a drag of 120” is giving an instruction that transfers between machines in a way “set the damper to 5” does not. Second, honest effort: because drag factor accounts for the real conditions, it stops you fooling yourself that a light setting in a warm room is harder work than it is.

How to set your drag factor

1. Find it in the monitor menu.On a PM5, it is under the “More Options / Utilities / Display Drag Factor” path. Row a few strokes and it settles on a number.
2. Adjust the damper to hit your target. Move the lever up to raise the drag factor, down to lower it, and re-check after a few strokes.
3. Start around 110 to 130 if you have no preference. Many rowers train in that band. Sprinters sometimes go higher, distance rowers often lower. There is no single correct number, only a repeatable one.
4. Keep the flywheel screen clean. A clogged screen quietly raises your drag factor over months — one reason a little maintenance keeps the machine feeling consistent.

A note on other machines

Drag factor is really an air-rower concept, and the Concept2 PM5 is where you can read and use it most precisely. Budget monitors on other air machines may not display it at all, which is one more reason the PM5 is the monitor the sport standardizes on. Magnetic and water rowers do not have a damper in this sense, so the concept does not apply to them the same way.