Slowman wrote:
Tom A. wrote:
Slowman wrote:
Tom A. wrote:
marcag wrote:
Tom A. wrote:
Hoo boy...I go out for a ride on a Sunday morning and all confusion breaks out... ;-)
Sorry. My fault :-)
Nope...you weren't the only one confused by those plots and their presentation. Not our fault...
what's confusing you? perhaps i can help. i have questions, for sure. but none of these charts have me confused.
I guess I wasn't clear enough above. The most confusing (or, perhaps, a better term would be "least enlightening") graphs are the delta plots, with no explanation of the baseline at each data point. It would be REALLY easy for them to show the baseline curve, and the rest of the curves for that matter, and THEN show the delta plot. The delta plot is really just a refinement of the data presentation. Without the original data, it's tough to put into context...especially if it shows (as these plots seem to indicate) unexpected behavior based on previous data/knowledge/modeling.
edit to add: Secondly, is the lack of details and transparency in the rolling road setup and protocol. IF they're using that data to point to these products somehow behaving differently than others do, then I think additional scrutiny of that methodology is warranted. Especially if the data from that methodology somehow doesn't match well with previously established methods.
It just seems like a bunch of hand waving right now...reminds me of the "old days" of wheel claims, actually ("It's faster...trust us!")
i don't suffer from the lack of that underlying data you ask for. i don't feel i need that data to understand what zipp is trying to express with these graphs. however, i respect your view and honor your background in this, so i don't mean to minimize your desire to see the data not supplied.
as to the rolling road, i might misremember but i think this is the second time "lack of transparency" has been used as a descriptor in this thread and, again, unless i misremember you've been the user both times. to me, this connotes and intentional act to withhold data. i gave you the protocol. rider aboard, 85 kilos rider + bike, roll up to speed for 30sec, the test runs for 90sec, rider dismounts. there were 96 total runs. there were 24 set ups tested (a given wheel with a given tire width at a given pressure). to me, dividing 96 by 24, that means they performed 4 runs per set up. zipp says the rolling road is a "standard" to use their word road surface, analogous to their eagle creek field testing circuit.
if what you want is a picture of the rolling road, i'm pretty sure one could be provided. do you want the speed of the rolling road? the speed of each test? i'll ask. but i don't see the lack of transparency you see. perhaps you could tell me what it is you don't see and i'll see if i can get it for you. just, if you're going to ask for data beyond that which is typically given by drum testers, such as you or al or BRR, then i have to cry foul. sauce for the goose and all that.
I think the issue is exactly that there isn't enough transparency with this testing. All the claims they are trying to make are that their rolling road is a good simulation of real world with no data to back it up or even details on what type of road surface is being simulated especially as road surfaces are super variable.
Along the same note people even don't believe wind tunnel test and that's very well established with decades of validation and everyone is well aware of the assumptions and limitations involved in wind tunnel testing. Asking other engineers to believe an entirely novel setup without any validation or even pictures/description of the setup shown to them is going to be an uphill struggle. Listing out the number of runs, rider weights, how long they road for before testing isn't really useful in my opinion. That's small peanuts and is taken as a given that those things are controlled. The real important questions are as mentioned before behind the actual rolling road setup. As if that doens't simulate road riding or the representative surfaces I or others ride on, the results won't be meaningful no matter how much control there is of test setup. I want to believe that it simulates actual roads well, but having experience building test apparatus to simulate real life events, I know how difficult that is.
This is part of the reason the track "data point" I mentioned is so impactful to me. We know the test apratrus is good (the track), the main source of error (the rider) likely well controlled due to rider skill, and the test setup is likely good. Plus this is on very smooth surfaces which is a regime with sparse low pressure data. If much lower pressures are good on smooth surfaces, then it's a given that they will be good on rougher surfaces. Instead most of the testing thus far has been on quite rough surfaces which makes me believe that the benefits aren't there on smoother surfaces, and that this testing (if it is an accurate simulation of road riding) represents rougher surfaces to show a larger benefit.
Echoing what Tom said I'd like to know the following about the rolling road testing and will likely have more follow on questions once I see a diagram of the rolling road setup and a picture/cross-section of the surface. However I'll assume the Zipp engineers have the normal environmental, sensor setup, and sample preparation variables well under control.
- Do you have a diagram of the surface of the rolling road setup?
- How is each section/plank of the rolling road supported when rotating through the treadmill/how large is each section?
- What does the transition between sections/planks of the rolling road look like?
- Do you see periodic events correlating to the load/unloading of a new section/plank or the transition between sections?
- How is the micro/macrotexture on each section/plank of the rolling road applied?
- What surfaces are you trying to simulate?
- Do you have PSD's between the rolling road and the surfaces you are trying to simulate?