marcag wrote:
BigBoyND wrote:
Tom A. wrote:
And then they say the aero data is with a 25mm tire (for comparison sake to past data) but then don't also show what it is with the 28? I'm sorry...that's just not kosher...especially if they say they don't show the Crr data on the older wheels with the wider tires. Sure, it was "optimized" around the 25mm, but THAT is an aero effect, not Crr. It reads like they're cherry picking the results.Yeah I'd like to see CRR and aero for both wheels with both tire sizes. Otherwise Zipp is assigning the RR gains that come from a larger tire to the new wheels but not for the old. What tire size they're "optimized" for is rather meaningless in this context. The old wheel might save the same 4W on RR with a 28mm tire.
And stating the obvious (not to you specifically)
this is why a Chung test should be done, old wheel with 25, old wheel with 28 and new wheel, on a "reasonable" road, representative of most triathlons. Ideally at a few pressures, pick the best number for each combination.
We will then see the real world difference. This is trivial to do if one has access to the wheels
Or...if one has wind tunnel data from the tire/wheel combos of interest, along with Crr data of the same combos from roller testing, it's actually possible to come up with an "overall estimate" that can be useful in evaluating which is faster, and when ;-) Such as here: https://bikeblather.blogspot.com/...t-3-after-party.html
Field testing of some of the combos of wheel/tire/pressure could be a good confirmation, but performing that testing isn't always the easiest to accomplish and is very time consuming, IMHO.
http://bikeblather.blogspot.com/