Roller calculation

On 22 Jan 2004 16:46:07 -0800, [email hidden] (Scott J. Thor)

Quoted message said:

I have two sets of rollers. Set A is 2.25" Set B is 4.5"

What formula can I use to determine what my performance will be on the larger rollers based on what
I can do on the smaller rollers?

You have rolleritis. I suggest an anti-inflammatory such as ibuprofen or naproxen sodium and
excision of one set of rollers.

You can donate the waste from your rollerectomy to some poor soul who has no rollers at all --
namely, me.
--
Rick Onanian

"Scott J. Thor" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I have two sets of rollers.

Set A is 2.25"

Set B is 4.5"

What formula can I use to determine what my performance will be on the larger rollers based on
what I can do on the smaller rollers?

Good luck. Assuming bearing friction is equal it's the ratio of rolling resistance where the smaller
roller will have a higher resistance. Tire deflection and contact patch is quite a bit different so
this is not the simple application of a single formula. If you could borrow a bicycle with a Power
Tap you could calibrate the rollers and failing that you could use the less accurate method of
comparing heart rate for your level of effort.

Phil Holman

I did a comparison of Kreitler rollers, power vs. speed. The data, along with power vs. speed curves
for trainers, is at

geocities.comtrainerpowerOpen ↗

The data for the Kreitler rollers is about a fifth of the way down the page, the blue and green data
on the plot. Different sized rollers and different tire pressures would change the curves.

As can be seen from the plots, the power vs. speed curves are very different for rollers vs.
trainers. I also note that the "feel" of pedaling is also very different, rollers vs. trainers.

Regards,

Tom Compton www.AnalyticCycling.com

"Scott J. Thor" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I have two sets of rollers.

Set A is 2.25"

Set B is 4.5"

What formula can I use to determine what my performance will be on the larger rollers based on
what I can do on the smaller rollers?

Quoted message said:

Quoted message said:

the power vs. speed curves are very different for rollers vs. trainers.

No headwind fan on the Kreitlers I assume. That makes a huge difference so the dots would move to
the left and, I'd guess, curve upwards like the trainers.

--
Jim