Watts Bike erg 4K vs Rower 2K, different watts?

[DamirDukdalf]

Hi all,

For the last month, due to an injury, I have been training on the concept bike.
I don't have clipless pedals and I'm wondering how the watts produced on the rower
compare to the watts produced on the bikeerg.
For example, what do you do on a 4K on the bikeerg and what do you do on the rower?
When for example, you go 6.10 on the bikeerg, does this also compare to 6.10 on the rower?
When I look at ergathlon times for example, you don't see big differences in the rowing times vs the bike times.
Maybe you guys can help me out.

Best regards Maarten

[Nomath]

According to the C2 website, the BikeErg uses the same flywheel and Performance Monitor as the RowErg to measure power (watts). So the watts will be exactly the same. What is different is the associated speed of bicycle or boat. Since the speed of a stationary device is an imaginary attribute, the designer is virtually free to chose. Apparently, for the same input power, C2 has chosen to let the BikeErg move twice as fast as the RowErg,

You are confusing the question by referring in the title to 'Watts Bike'. This is almost the name of another brand of exercise bike that uses a different resistance type (magnetic instead of air) and a different method to measure power.

[DamirDukdalf]

Allright, thanks! But the rowing motion isn't continuous and the cycling motion is. Therefore I'm wondering, if you have a certain output on the bikeerg, can you translate this directly to the rowing erg?
So perhaps, if I go 6.10 on 4K cycling, am I able to go 6.10 on a 2K rowing? Given that you're technique is quite good on both the machines.

[MartinSH4321]

This depends on many different factors. In general, the bike motion is more effective than the rowing motion, according to studies it's about 25% vs. 20%, which means a person needs the same amount of energy to produce 200W on the rower or 250W on the bike.
However, there are other factors like technique and distance. On the rower you can use more muscles to produce power which is an advantage for sprints. The fastest rowers do more than 1000W for one minute, more than anyone has ever done on a bike if I remember right. The longer the distance, the better for cyclists (see Hamish Bond for example).
No idea where the intersection is, but I would guess around 2k.

[jamesg]

Difference is probably 15-20% Watts, which translates to 5-6% speed and time. However there may be individual differences due to bodyshape, technique, specific training and so on. Those who have both items can no doubt tell those who don't all about it. Why don't we see such info here?

[faach1]

This depends on many different factors. In general, the bike motion is more effective than the rowing motion, according to studies it's about 25% vs. 20%, which means a person needs the same amount of energy to produce 200W on the rower or 250W on the bike.
However, there are other factors like technique and distance. On the rower you can use more muscles to produce power which is an advantage for sprints. The fastest rowers do more than 1000W for one minute, more than anyone has ever done on a bike if I remember right. The longer the distance, the better for cyclists (see Hamish Bond for example).
No idea where the intersection is, but I would guess around 2k.

I agree too that the crossover point is likely around the 2k mark.

[ArmandoChavezUNC]

I caution anyone trying to equate watts on the bike erg and the erg - they are different movements involving different muscles and physiology and thus you should not expect them to be equal.

If you really want to compare, do a maximal test on each to give yourself a baseline.

[CaseyClarke]

I have both. I’ve been well trained at rowing in the past and I’m well trained in cycling currently.

There will be differences for individuals, but typically, peak power on the bike is higher than on the rower. Think of the absolute best rowers who can peak around 1:01-1:03 split (1300-1500w) on a row erg during their peak speed on a 100m sprint. I know of several people hitting these power numbers on BikeErg and no doubt heavier more powerful track sprinters would be several hundred watts higher.

Power in the 20 second to several minute range favours the row erg. This is from the anaerobic glycolytic system.

And then when stuff starts to get far more aerobic, say 2k erg / 4k bike being the crossover point, the power numbers will favour the bike. All of my bikeerg distance PB’s are far higher watts than the rowing equivalents. Also look at the hour WR on the erg. It’s around 400w. On the bike it’s perhaps 10-15% higher.

[rtbrouwer]

I do cycling as well as rowing.

My personal best on a 2k is 6:48 which equals 330 watts
On a recent PB attempt on a local climb I averaged 395 watts for 5 minutes. So 7 minute power would probably be around 25 watts lower @ 370w

Earlier this week I equalled my PB on a 5k row @ 18:17 which equals 265 watts.
On a 10k timetrial on the bike last month I averaged 345w for 14:36 and a week before that I averaged 333w for 20 minutes. So lets say my 18 minute power on the rower is at 265 and on the bike somwhere around 335-340.

My best wattage on the rower for 60 minutes is 235w
My best wattage on the bike for 60 minutes is 308w

It seems to me that the difference between Rower and Bike grows when the effort gets longer. But those are all my own personal numbers. Might be different from person to person.

[flatbread]

Because off the difference in torque load (100rpm on the bike vs. 30spm on the erg, for instance), the power-duration curves are going to be different.

Cycling, a fit elite-level rider should be able to sustain about 85% of 6min watts for 60minutes. Kurt Jansen's erg tables show 60min to be more like 75%. For non-elites, you can probably knock 5% off each of those numbers.

2k power is about 80% of 5min bike power, for most folks. 60min erg power is more like about 65-70% of 60min bike power.

I'm not well-trained on the erg, and the highest 2k power I've seen is 300w. I can do about 380w for 7min on the bike. Hour on the bike, 340w right now. On the erg? Maybe, maybe 235.