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  1. #1
    Senior Member IronHorseRiderX's Avatar
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    Rolling resistance test - Vittoria Open Corsa vs Grand Prix 4000S (700x23 clinchers)

    I purchased some time ago Elite Arion Parabolic Rollers from Nashbar and luckily only used them few times as weather turned out so much better than expected.

    Also I changed tires from Vittoria Open Corsa (SC if I remember correctly) to Grand Prix 4000S (plain S not newer S II) in between those rides.

    Here's my test data for average 25 sec power:

    Vittoria Open Corsa: 206W ( 31.1mph @ 95rpm )
    Grand Prix 4000S: 193W ( 31.1mph / 94rpm )

    Here's screenshot with actual graphs https://farm8.staticflickr.com/7286/...41424c26_o.jpg

    Both inflated to ~100 psi

    13W is quite a difference (5% no less) and not the one I expected as in most (all) tests I saw so far Vittoria Open Corsa was right on top of the charts.

    It is not clear to me how resistance on rollers would be related to resistance on actual road so this is mostly for my amusement.

  2. #2
    Senior Member nastystang's Avatar
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    if I am reading that right one is 15 seconds and the other is 25.
    That is the time on the top of the graph right.

  3. #3
    Senior Member IronHorseRiderX's Avatar
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    Very true - I should of paid better attention
    Still looking at graph it would not change outcome.

  4. #4
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    Quote Originally Posted by IronHorseRiderX View Post
    Here's my test data for average 25 sec power:

    Vittoria Open Corsa: 206W ( 31.1mph @ 95rpm )
    Grand Prix 4000S: 193W ( 31.1mph / 94rpm )

    Here's screenshot with actual graphs https://farm8.staticflickr.com/7286/...41424c26_o.jpg

    Both inflated to ~100 psi
    Only one test of each tire? Do five tests of each where you let air out and re-pump to pressure so we can see how repeatable your test is. For all I know, the difference you see between tires could be equal to what you would see using the same one in two separate tests.

  5. #5
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    best way to present the data: redo each one 5 times, average the 5 trials for each tire, and then find the standard error, plot it in excel with errors bars, then find if the difference is statistically significant using t-test.

  6. #6
    Senior Member IronHorseRiderX's Avatar
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    Here's actual rides on strava https://www.strava.com/activities/256898212 and https://www.strava.com/activities/230440005
    I'm way too lazy to re-pump and also no longer have working set of Open Corsas anyway.
    After putting about 500 miles on Grand Prix 4000S I can tell that those extra 10W (assuming they for real) did not made me go noticeably faster (or slower for that matter).
    So far I'm very pleased with 4000S - they will last longer for sure, seems to have superior protection from road debris and much better grip in wet.
    They do have bumpier ride thou - hard to argue with that

  7. #7
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    What power meter are you using? Torque zeroed? Same tire pressure, room temperature, weight, inner tubes?

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