RojoRacing
Donut Powered Wise-guy
I wish I could hop on my DF bike and perceive 300 watts as if it were a mere 200.
Coast Down testing with Larry Oz!
- Thread starter LarryOz
- Start date
I wish I could hop on my DF bike and perceive 300 watts as if it were a mere 200.
I really believe if it's possible to do this, you will find a way!
super slim
Zen MBB Master
Try a S40 to see how easy the extra power can be applied, but at an Aero disadvantage!!!
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ak-tux
Zen MBB Master
My point exactly. The total average speed over a mixed course depends not only on aerodynamics but the power the rider can generate.
"A more aerodynamic position whether recumbent or upright would not necessarily increase the speed if it puts the riders body in a posture that limits his/her ability to generate optimal power, consistently, over the entire course."
In my humble opinion, besides the stiffness and integrity of the frame, there is something about the position of the bottom bracket relative to the rider's torso that affects power output.
I wish you could subject the S40 to the same tests above and how many watts you'd be able to generate pedalling back up the grade.
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super slim
Zen MBB Master
It would be good if Larry could Borrow a S40 AND a S30 to do these roll down tests, AND what about a QX100 and a T50, with 26" full disc wheels, just to see the difference of the Utility bikes to the touring and race bikes, for the same rider!!!!
LarryOz
Cruzeum Curator & Sigma Wrangler
Yeah - I have had quite a few come up my trailer and ask me questions. Earlier there were about a dozen construction workers prepping a driveway for concrete. I am sure they got a kick out of it!
super slim
Zen MBB Master
Were they asking where they could buy one?
LarryOz
Cruzeum Curator & Sigma Wrangler
Yeah right! They were more looking at me like I was from another planet!
benphyr
Guru-me-not
Hi Larry,
I think I missed some history somewhere? This is trying to be helpful - some of us detailly people notice weird things and trying to help.. While avoiding other factors like positional efficiency, drivetrain efficiency, etc. doesn't this test still have weight (force of gravity) as a big variable of the acceleration/deceleration that comes into play besides the aero comparison that is being aimed at? or are all the bikes the same mass / weight (presumably you Larry maintained a relatively stable mass throughout the test
. Rotational mass was mostly taken care of by using the same wheels, hubs, tires combination except for the Arrow that would not fit the same wheels and was tested later against the Giant. What do you think Larry?
Ben.
I think I missed some history somewhere? This is trying to be helpful - some of us detailly people notice weird things and trying to help.. While avoiding other factors like positional efficiency, drivetrain efficiency, etc. doesn't this test still have weight (force of gravity) as a big variable of the acceleration/deceleration that comes into play besides the aero comparison that is being aimed at? or are all the bikes the same mass / weight (presumably you Larry maintained a relatively stable mass throughout the test
. Rotational mass was mostly taken care of by using the same wheels, hubs, tires combination except for the Arrow that would not fit the same wheels and was tested later against the Giant. What do you think Larry?Ben.
jond
Zen MBB Master
No way Larry mate your power meter was merely disgusted to be slumming it and spat the dummy.
And may I say personally whilst it took a year the vendetta power ended up the same as the df for me with no disparity just comfort lol.
jond
Zen MBB Master
Dedication Larry. At this very pointy end of performance consistent informative results as expected seem to be somewhat frustratingly elusive. As suggested earlier I guess a heavier rig would roll down faster. In the end no matter you will be fast.
LarryOz
Cruzeum Curator & Sigma Wrangler
You are correct Ben, and if I had had the time I would have liked to have built all the bikes and weighed them and then added ballast to all the lighter ones to make them all even. Problem was, that for many of them I was stealing and swapping parts so all the parts were as equal as possible. I did weight each bike and myself at the beginning of each run and meant to post that data as well. I just can't find my log book anywhere right now. From what I remember though, all the weights where really close to each other (with 0.5%), with the exception of the upright. One final comment is that I designed the coast down test to not include the initial seconds off the ramp, and also had one incline to to climb in the run-out. Both of these there factors would tend to minimize the effects of greater mass and gravity to gain a faster overall speed.Hi Larry,
I think I missed some history somewhere? This is trying to be helpful - some of us detailly people notice weird things and trying to help.. While avoiding other factors like positional efficiency, drivetrain efficiency, etc. doesn't this test still have weight (force of gravity) as a big variable of the acceleration/deceleration that comes into play besides the aero comparison that is being aimed at? or are all the bikes the same mass / weight (presumably you Larry maintained a relatively stable mass throughout the test
Ben
McWheels
Off the long run
Looks to me that we need one of these: http://www.cyclingweekly.com/news/l...able-wind-tunnel-testing-to-the-masses-208242
bladderhead
Zen MBB Master
Larry is blindingly quick even when he is coasting. I noticed that the icon at the bottom right of the video is a DF bike. Larry should get his camera fixed.
