Rollers and Wattage Question

[keno]

For anyone with Kreitler Challenger rollers and a Power Tap or SRM, what wattage do you generate in 53/12 at 30 mph? How much do you weigh?

260 and 184 for me, but looking for similar results from others before I believe it. If I can hold 260 watts for 30 minutes or more, I'd consider it a workout.

keno

[Too Tall]

KenOboyO - I'll give that a shot this weekend. I can tell you this, holding that wattage is a very solid workout indeed. It works out to a solid 3.06 watt / kg and is what a strong cat 4 rider might avg. for a similar time period. Dewd, you be strong.

[ergott]

Don't forget to factor tire and more importantly, tire pressure. Lower pressure will increase the resistance.

[manet]

For anyone with Kreitler Challenger rollers and a Power Tap or SRM, what wattage do you generate in 53/12 at 30 mph? How much do you weigh?

260 and 184 for me, but looking for similar results from others before I believe it. If I can hold 260 watts for 30 minutes or more, I'd consider it a workout.

keno

what sort of penguin is on the telly when you are doing this?

[Too Tall]

No soap, radio.

[keno]

ergott, I think that the inverse may apply as to tire pressure, if I understood the folks at Kreitler when I asked about the various models. Here's why. What they told me was that, in the case of smaller diameter rollers, the contact area of the tire on the rollers is smaller and consequently the resistance greater. From that it would follow that lower tire pressure increases the contact area and lowers the resistance.

I think that I will take this one into the lab and try 100, 110, and 120 lbs at same speed and gearing and report back at some date in the future. Of course I could save all of that trouble and just call them, but that's not what Mr. Wizard would have done.

keno

[flydhest]

keno,

I think the point about the smaller contact point with the smaller rollers is that it causes more deformation at the same pressure and thus more resistance. I think ergott is right about lower pressure causing more resistance . . . for the same reason.

Pressure is in psi, so hold pounds constant but make si smaller (in a smaller roller) and you get more deformation. Similarly, hold si constant (that is, keep the same rollers) and lower p, you get more deformation.

[keno]

it reminds me of freshman year physics, going into the lab to learn about Brownian Motion. A major difference is that then I wasn't interested. I don't care how my experiment turns out; I just want to be blinded by science. Maybe a Nobel prize for roller research?

Further, fly and ergott, take a look at http://www.kreitler.com/fs_techinfo_item.php?item_id=15&calling_page=%2Ffaq.php.

keno

[zap]

Keno-very true, more is not always better. Heat build up is a pain. Ask tt about that explosion some years back when we were racing indoors.

I can't hear you!!!!!!!!!!!!!!!!!!!!!!!