“The tires are almost the same actual width, and I’ll put 120 pounds in each one.”
Doesn’t 120 exceed the maximum PSI recommended by Michelin for the ProRace?? 
“The tires are almost the same actual width, and I’ll put 120 pounds in each one.”
Doesn’t 120 exceed the maximum PSI recommended by Michelin for the ProRace??
How much do you weigh again? I think my Michelins are happier than yours at 120lbs.
I see this as somewhat meanful for younto determin which is the fastest front wheel for you, but rather meaningless to determine whcih is the best tire.
At the very least you must let us know what figure you will be using to equalize the aerodynamic/weight/hub/ diferences of the two wheels before you do the test. Obviously you wouldn’t have dropped serious coin on the new wheel if you didn’t think it wouldn’t be faster, so any “fudge” factor has to be disclosed before the test, not after or you can make the results come out anyway you want.
Secondly I would like to see the actual PT date not just overall numbers. A dead sprint 6 time during one trial with a slow recovery in between may give the same ave speed /watts as a steady effort, but would skew the results.
I’m honestly not saying that you will try to purposely skew results, but short of a double blind test (impossible in this case), full prior disclosure of test methods is only sensible.
Styrrell
Measured down to the meter? If not, the data could be off. Just a thought.
Off yes, but off enough to void the results – probably not. A PT allows for setting rollout down to the millimeter.
It’s one thing to miscount by dollar if you are counting to a thousand dollars. It’s another thing to be off by a dollar if you are counting to three dollars. We’re counting to a thousand here.
Yeah…the problem here is that people just will not be satisified with any results that might come from such a test. I still think it might be interesting to do but controlling the variables is basically impossible. Worthwhile results could certainly be gained by doing many runs over a lot of time (and energy) and in various conditions but I doubt anyone here is going to want to do that.
People are looking for something they can point to as “the definitive answer™!” but they won’t get that here. Suffice to say that those of us who have logged many miles on these tires (and many of us using power devices and critically examining the results) are looking elsewhere. Those who feel we are raving lunatics without a shred of evidence should feel free to continue using these tires - just don’t be surprised if you find yourself in a good aero position churning out 22.5mph at 280watts…
ot
At the very least you must let us know what figure you will be using to equalize the aerodynamic/weight/hub/ diferences of the two wheels before you do the test.
Sure, fair enough. The 404 will get about 15-20 seconds per 40k speed handicap to the 808. The exact figure will come from a white paper on Zipp’s website that I have at my office. I will make no adjustments for hubs. Other people have concluded that high quality hubs have a nearly immaterial difference. Will the hubs make a difference? Sure, but I dare anybody to try to measure it. We can ignore it.
Look, if the tires are different enough, it will be apparent by drowning out all this little stuff.
The main problems, as I see it, are (1) only the front wheel, possibly making any difference too small to detect; (2) weight shifting by me as I ride; and (3) the glue factor will remain unknown. The 404/Tufo wheel has 1-year old Continental tubie glue on it. Other researchers have concluded that track glue is faster.
I will do 100% of each ride in the aerobars (to both load the front wheel and to minimize body movement) at as constant a power as I can muster. If I vary too much, it will be apparent in the PT data file. Small variations don’t matter. Big ones could be problematic (although I am not totally convinced of that).
I make the suggestion that the glue setup I am using is a fair test, since that is how people mount these tires out in the real world. We’re not trying to determine if the Tufo is as fast as the Michelin under perfect, idealized conditions that favor the Tufo in every respect – we’re trying to test them the way people really ride them. For that reason, BTW, the Michelin will have a standard training-type inner tube, not a fancy latex tube.
Damn, hit a guy where it hurts!!
I just got back from Hawaii and got on the scale. It was the heaviest I’ve weighed in over two years. Grrr. So I’m sure your Michelins are happier than mine. After work today I’m going to try to ride until I puke.
Everything in moderation…
Ashburn,
I’m glad you are doing this and am looking forward to the result. I did a practice run on a 10 mile out/10 mile back yesterday to see how the 2 runs compared. I’m much slower than you so I held about 130 watts - my runs went like this: (same wheels with each).
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133 watts out, 33:57 time, 90 cadence
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132 watts back, 36:59, 88 cadence (more up on the way back)
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133 watts again going out, 33:35, 90 cadence
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133 watts back, 36:40, 87 cadence.
So with watts close - and I paced o.k. but wasn’t super rigorous - it was just a trial. There was some wind - may have changed a bit as IO went. Course goes east then south and returns so I go in all directions…I had a 20-30 seconds difference over 10 miles which is about a 1/3 mph which should be about 7 watts. I did lose a little weight in water bottles as I went but thats only 2-3 pounds. I was about 95% in aero bars. Data drom PT looked at on the PT not the computer (my computer crashed).
I think I could pick up a 10+ watt difference between wheels if I did the test with 2-4 runs each day for 2-3 days…
1 wheel only with a 5-10 watt difference would need more runs I think.
Dave