asgelle

It substantiates my claim that there are not a trivial number of tests at other than 0 yaw (I count 48 maybe you consider that a trivial number, I don't). It also shows that drag drops with increasing yaw, but I guessed you missed it).

As to only going out to 30 degrees, have you ever considered what conditions are necessary to have yaw angles greater than that? Have you ever experienced it?

asgelle

Here's 12 more. https://forum.slowtwitch.com/Slowtwit...0_TT)_P2609085

umd

Both of you fail. You didn't pay attention to asgelle's answer. They didn't have super-deep carbon rims to use on the front like they do now. Why use a disc when you can use a massively deep rim, still get most of the aero benefit, and better handling.

vsopking

Nice bike... but what's with the saddle? Sort of a nutbasher?

neuronal

Still waiting...

Are you seriously saying that you've never experience apparent wind at more than 30 degrees? Cycle much? I'd like to see some credible (i.e. a source not financially invested) source with data up to 75 degrees, which is more than likely what the guy you were disputing earlier was talking about.

You also failed to consider how much harder it is to ride in a crosswind with disc wheels, steering-wise. When someone says "I notice much more work in side wind when using a wheel with a deep rim but the hill climb rims can also make for a twitchy ride on a very windy day." and you tell them they are wrong, please have actual facts to back it up. You implied there were plenty of such tests, I asked for 2 and you've given 0 relevant ones.

neuronal

tldr. Do you have the link to the data/results?

Also, this looks like marketing drivel. I'm not looking for Easton PR, I'm looking for a legit test comparing the wheels and data.

Grumpy McTrumpy

you are in over your head.

BTW if you bothered to click on that link I posted on page one, it explains yaw angle in detail and includes a calculator for any speed and angle of wind, as well as bike speed.

asgelle

Are you saying that Zipp and Hed lied about actually performing the tests. Since the question was the number of tests, the results are irrelevant. You are now claiming that these two companies are claiming results for tests they never performed. Given how many independent testers have reproduced the results (Google is your friend) this would seem highly unlikely. Anyway. Here's a source for independent test results. https://www.biketechreview.com/aerody...8_trispoke.htm (note this write up refers to another test series as well) and a few more https://www.biketechreview.com/aerody...els_tunnel.htm and https://www.biketechreview.com/aerody...aero_forks.htm

And hey, look what Kraig has to say about yaw angles in the last reference,
"In order to evaluate overall aerodynamic performance, it is essential to measure the sample’s properties over a representative range of yaw angles. It was assumed that the appropriate range of yaw values for cycling is 0° to 20°. There are certainly occasions in which the yaw angle exceeds 20 degrees, but it can be argued that these situations are rare."

But what does Kraig Willett know?

neuronal

I'm not following how this is relevant. With normal wind conditions in Boston, it's extremely easy to have an apparent wind angle of 60-70 degrees.

Clarification: I'm not claiming that deep rims don't reduce drag. I'm just saying that the earlier remark about how "every test IRL and in the wind tunnel show that it's easier to ride with deep rims" is false.

Grumpy McTrumpy

baloney.

I dare you to ride in those conditions with any wheels. You'd need a day with a 30mph sustained (not gusts) wind speed just to get the results you are looking for.

This is not about science. It's about a silly pissing contest where nothing anyone says will ever cause you to realize "gee, maybe I was wrong about something"


pointless argument.

neuronal

I can see that I was unclear in what I was asking. I was not asking for different angles on the same wheel. I was asking for data on different angles on many wheels. You've finally given a link to such a test (thank you, but I don't have access to the results).

asgelle

Sadly, that is not what you were saying at all. Do I really need to remind you what your first words on this subject were? O.K.

neuronal

Try:
rider at 18mph
wind at 15mph, 310 degrees

This is pretty much how it usually is around where I live (well, the degree changes, but the wind speed is usually 10-20mph).

neuronal

The "What the hell are you talking about?" is referring to your claim about wind and work. The second sentence is a different subject. Like I said, I was unclear in my first post, but most of my later posts should have made it clear.

Grumpy McTrumpy

you do realize that is a tailwind?

neuronal

Set the wind to 90 degrees then. Point still stands.

neuronal

Well, this has been a pointless argument and all, but you guys still have failed to convince me that deep rims are better in a decent crosswind (which is the context of this thread). My original beef had been with this claim, and I've yet to see any data that supports it (even though apparently a lot of such data exists?)

asgelle

Zipp data, Hed Data, Biketechreview data, model results at analyticcycling.com, endless discussions at slowtwitch.com, and much more if you'd be willing to look at it. What exactly are you looking for?

umd

I think you two are just talking past each other, not about the same thing. Deep rims may be harder to handle in a crosswind, but that doesn't mean that they aren't beneficial from an aerodynamic standpoint.

neuronal

I am asking for data that includes angles up to 75 degrees, though I suppose 55 degrees would be enough at this point. 75 is a bit rare. I can see that ZIPP did stuff up to 30 degrees, but that wasn't enough.

The point is, if you are right and deep rims are better in heavy crosswinds, you should have data that says that the drag is significantly lower to offset the increased difficulty in handling, especially for angles that are more realistic for heavy crosswinds.

neuronal

I agree. The question is whether or not the decrease in drag is significant enough to be worth it. Of course, this is opinion-based, but I was looking for data anyways.

asgelle

Steve Hed, Josh Portner, Kraig Willett John Cobb, Andy Coggan and others have all decided that yaw angles above 30 degrees are so rare as to provide no meaningful benefit from the results. They have also studied wind tables and rider speeds and determined that the most likely angles lie between 5 and 15 degrees meaning 30 or even 20 degrees provides a good margin. You on the other hand, feel they are inadequate in their estimation and are neglecting the important area out to 75 degrees. I'll leave it to the reader to decide who has more credibility.

neuronal

As the HED wind gadget says, riding at 18mph with a 15mph crosswind gives an angle of 40 degrees, and a 20mph wind gives an angle closer to 50 degrees. And if you live in a windy region (we were getting 60 mph gusts here recently, where the apparent angle is about 65 degrees), it is not that rare to see high angles.

Keep in mind, no one is talking about normal or average riding conditions here. We are talking about crosswinds (or as everyone assumes, strong crosswinds). Sure, 90 percent of my riding is in an apparent wind angle of <15 degrees, but that is not the topic of this thread.

So once again, I ask you, do you have any data to back up your claims?

asgelle

You're not solving the right problem. Rider speed and wind speed/angle are not independent. Rider power is fixed. If the rider can keep a speed into a dead headwind, as the wind clocks around, the rider will go faster and the apparent wind will move nearer to head on. Use analyticcycling.com for power given speed and iterate on a rider speed and true wind to calculate the true rider speed for a fixed power and crosswind. Then use that in the HED calculator and see what happens.

Also you have to use wind speed at 1 meter above ground level. Weather stations usually report at 10 meters. The boundary layer at ground level means the speed at 1 m is much lower than the free stream above.

neuronal

What you've said may be true, but that's besides the point. I'm sure I've ridden at 18mph in both 15 and 20mph crosswinds, even if measured at ground level. In fact, I've ridden in much higher winds. Granted, I am slower in heaver crosswinds, but then the apparent wind angle only increases and emphasizes my point. I was merely demonstrating that it is not rare and definitely not unrealistic to have apparent wind angles of >30 degrees.