Agreed.


Well, it seems that a random error can be ruled out, since the two sets of runs yielded values for rolling resistance that were w/in 10% of each other.

As I mentioned before, an error in setting the SRM offset and/or slope can also seemingly be ruled out, as 1) the rider is a long-time (i.e., >10 y) SRM user, and thus quite familiar with the device, 2) the offset was consistent with expected values, and the slope was checked afterwards and found to be correct, and 3) when using a fixed gear, an error in either the offset or slope would impact the estimated CdA, not the rolling resistance.

Allen Lim hypothesized that perhaps the lighter rider was "driving it" harder in the turns, thus increasing tire scrub, but this isn't borne out by comparing the power data of the two athletes. (BTW, I have reason to believe that he has also gotten high values for rolling resistance on the ADT track...perhaps because the riders he tested also over-inflated their tires?)


Except that even, e.g., really tight hub bearings wouldn't increase rolling resistance by that much, or in a linear manner.

I measure on the road two wheels with mass applied we have standard weight is 70 kg total
I can apply any extra or less mass

i measure at 1000 samples a second in grams

Here's what I've revealed before:

http://forum.slowtwitch.com/gforum.cgi?post=1818159;search_string=pressure%20crr%20plot;#1818159

I've got a neat plot that I can post later (I don't have access right now).

But it's rigidly attached, correct?

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http://www.ada.prorider.org
skype ceesbeers191053

How "soft" is the wood of the ADT track?

to summarize, there were two different riders, two different weights, I'm guessing on two different bikes, and the rolling resistance calculated for one was much less than for the other rider.

My question is, did you then have the two riders swap tires and then compare the data again? If so did the two riders then swap rolling resistance values? Thanks!

Not exactly. Hands and butts absorb energy, no?

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http://bikeblather.blogspot.com/

Yes, any information on your experimental methods and the test data would be enlightening, I looked through the threads you link to and saw nothing of the sort.

As for the old "higher pressure" argument, well, that's just silly (off the track at least).

I've yet to see any convincing data to support the fact that higher pressure results (at some point) into higher rolling resistance (on a rough road), so i would say it's silly to say the argument is silly. The bumpy roller data sets (biketechreview) shows the same trend as the smooth roller data (decreasing RR with increasing pressure).

Francois in Montreal

Not exactly. Hands and butts absorb energy, no?

Well i measure a pulling force so the force that need horizontal,
so if the other force (read bump) is there it has tiny or small to zero effect to the horizontal force.
If there is a force then its filterd out


Hope you understand this explaination

cees

Here's what I've revealed before:

http://forum.slowtwitch.com/gforum.cgi?post=1818159;search_string=pressure%20crr%20plot;#1818159

I've got a neat plot that I can post later (I don't have access right now).

I'll be eagerly waiting for the plot. I'll then decide if it's worth my time to do some testing of my own.

Francois

Maybe I missed this, so please forgive me...

These tests/data/arguments/etc are for a tire riding in a straight line, yes? That's great, but what about when the tire is at an angle, like on a turn? Sure, we all ride straight but we also spend time turning too. Additionally, our handlebars do wibble and wobble about a bit since our balance is not 110% perfect. Do the tests take this into account?

-- Boris