Low Drag Numbers

mfd1068 · Post by **mfd1068** » March 10th, 2008, 11:40 am

Hello, I just purchased a use C model last week. I oiled the chain,checked the shock cords and cleaned the flywheel by removing the fan cage. The flywheel was not that dusty but I vacuumed it out anyway. The drag numbers seem to be low. 80 at 1, 115 at 5 and only 158 at 10. These readings are with a PM2 monitor.
Any thoughts on what I should check?

johnlvs2run · Post by **johnlvs2run** » March 10th, 2008, 5:14 pm

I'd remove the fan cage cover again.

Wipe off ALL the perforations with a damp cloth, then a dry one.

Be sure to do this both inside and out.

Replace the cover and check the drag factors.

mfd1068 · Post by **mfd1068** » March 11th, 2008, 1:37 pm

Thanks for the advice John. I did as you said and also removed the flywheel. I cleaned everything. The numbers where the same. No biggy, the machine works great and I'm using about 120 so its all good. Thanks for your help.
Dave

c2jonw · Post by **c2jonw** » March 11th, 2008, 2:30 pm

Hi Dave- I'm curious about this. What elevation is the machine being used at? C2JonW

Bob S. · Post by **Bob S.** » March 11th, 2008, 8:33 pm

c2jonw wrote:Hi Dave- I'm curious about this. What elevation is the machine being used at? C2JonW

That was my first thought as well. At a setting of 5, my DF ranges from about 114 to 121, depending on the temperature and any highs or lows that are passing through. That's at 4,000 ft. At 5000 or so, at like Denver, a average DF of 115 at that setting would seem to be reasonable.

— Break —

I got curious, so I just took a few minutes to go check out the erg and found that the DF was 182 at the highest setting. Considerably higher than the 158 that mfd1068 reported, but if he/she is at 5 or 6 thousand feet, it might well be consistent.

Which brings up another point. What is the usual ambient temperature in the room that houses the erg? I have noticed a drop one point of DF for a 2-3 degree Fahrenheit temperature increase in the room as a result of a long, sweaty workout.

If I weren't so lazy, I would dig out the relationship of DF and air density and make up a little table of DF versus P & T. Come to think of it, that would have made a great problem to hand out back when I was herding freshmen through Chem 101A. But I was retired by the time I first tried out an erg and it was another 15 years or more before I learned about DF.

Bob S.

mfd1068 · Post by **mfd1068** » March 11th, 2008, 11:06 pm

c2jonw wrote:Hi Dave- I'm curious about this. What elevation is the machine being used at? C2JonW

I am using the the machine at sea level. The flywheel is near a corner in my exercise room. From what I've read that placement will not affect the model C's. I was wondering if it could be the monitor?
I'm very happy with the machine.I was saving for a new model D when I found this one. The monitor indicated 60 km when I got it. Is that resetable?
I spent a couple months on the board,reading alot of info on the machines and the sport.The fantasy of having a rower and actually owning one is quite different.The Reality is ,that it is a tough workout!...lol, but you guys know that.Thanks for your help.
Dave

BrianStaff · Post by **BrianStaff** » March 11th, 2008, 11:20 pm

I just tested my new Model E (PM4) which is at about 1100 feet elevation

1 == 80
5 == 124
10 == 176

is that about right?

Brian

johnlvs2run · Post by **johnlvs2run** » March 12th, 2008, 1:15 am

mfd1068 wrote:The flywheel is near a corner in my exercise room. From what I've read that placement will not affect the model C's.

Having two walls by the cage could very well be the reason.

You can check this by moving the erg temporarily so the cage is in the center of the room.

Really though, there's no reason for having a DF higher than 158.

mfd1068 · Post by **mfd1068** » March 12th, 2008, 9:29 am

John,you are correct. The reason for the low numbers is the placement. I moved the erg to the center of my room and the numbers were 1-92, 5- 133 and 10- 208. I will have to use the erg in its corner placement due to space requirements,but like you said,the top drag # is higher than I'll use. Thanks for your advice.
Dave

rowland · Post by **rowland** » March 12th, 2008, 10:47 am

hey john,
good diagnoses.
John, I like your new picture with the dog.