So I saw a pair of Zed Tech wheels F/S. My question is.
The Zipp decals were so big and covered so much of the surface of the wheel, that there was probably less than %10 of the dimpled surface showing. Does that make a difference? The decals were not dimpled or formed into the dimples.
Just a random observation.
im not aware of any independent test on the effectiveness of the dimples at all
so to ask whether the stickers hinder that unknown effect is perhaps asking a bit much
.
Thank you Dr. Mott. I was hoping you would respond.
I’m pretty sure I recall a thread before that answered this.
I’m not sure if it was Jordan or Josh at Zipp, but I think the exact nature of the question was regarding stick on decals vs the year they baked in the decals.
The answer given was that it did not matter whether or not the entire surface of the wheel exposed the dimples to the airflow.
As the wheel is rotational, any area of dimpling serves to disturb the clean air, so having every single dimple exposed shouldn’t matter.
I’m pretty sure I recall a thread before that answered this.
I’m not sure if it was Jordan or Josh at Zipp, but I think the exact nature of the question was regarding stick on decals vs the year they baked in the decals.
The answer given was that it did not matter whether or not the entire surface of the wheel exposed the dimples to the airflow.
As the wheel is rotational, any area of dimpling serves to disturb the clean air, so having every single dimple exposed shouldn’t matter.
Correct. The stickers are also designed to hug the bottom of the dimples. I.e., in most cases, the dimples are still present even through the sticker.
People used the complain that the stickers covered the dimples. So Zipp baked them underneath, which (under vacuum) absolutely pulled the stickers into the dimples, so that you didn’t lose any dimpling because of stickers. But then people complained that the stickers looked “yellow” under the epoxy, so Zipp took them back out. You can’t please all the people all the time.
I am not aware of any data from Zipp that shows that it makes a difference if the stickers are there or not. BUT if you really care, you can take them off. It’s also not entirely clear WHY the dimples work. I.e., the data is there to - repeatably - show that it matters. But it’s not clear even to Zipp why that is the case. The modeling just hasn’t caught up to the results yet. The differences - and updates - to dimpling are the results of extensive testing. I.e., they don’t just draw a pattern and apply it. There are revisions, which is why the dimpling patterns are different on different wheels and why they have changed over time. But the results from different dimpling patterns if the byproduct of wind tunnel testing. I.e., there isn’t a way to predict (as far as I know) which dimpling patterns work the best. Only ways to test it, and of course, to make interpolations from testing. But there still isn’t a clear explanation as to why - or how - the dimpling improves aerodynamics, which of course, is why people challenge it. So that also makes it really hard to say whether or not the stickers make a difference.
Here is what I can tell you:
the dimpling patterns are the result of extensive wind tunnel development and testing by Zipp. The results show that they work, and that different patterns work better than others.
the stickers are designed to hug the bottom of the dimples, and dimpling should be visible through the stickers.
there is no data that shows that the stickers make a statistically significant difference. That is NOT the same as saying that they don’t make a difference, only that that can’t tell you certainly one way or the other.
I hope that helps at least a little bit.
is that data on their website?
is that data on their website?
Yes, it is in the Ask Josh section.