Aero data from 19 wheels by Hambini

[hambini]

To answer a few questions

I went to GCN in Bath last week. So it has been recorded. They are editing it at the moment. I didn't pay them to appear on the show and they didn't pay me to appear on the show.

regarding the wheel tests, some more have been completed. I need to put the data on the charts which is the next step.

Some people have asked what to look for in good wheel design. A few things

• Blunt vs sharp trailing edge, the more blunt it is the greater the yaw angle before separation occurs BUT the difference is 12 vs 15 degrees - so it's not much. The advantage with a sharp trailing edge is the flow from the wheel tends to be less turbulent and reattachment is better.
  
  Width - a bit of a generalisation. Ideally the width of the brake track should be around the same width or slightly wider than the width of the tyre. You can get energizing of the airflow and the very top of the tyre/wheel causes significant flow separation if you screw this bit up.
  
  Overall dimensions. There are some critical ratios that effectively determine the aerodynamics of the wheel. If you get these wrong (and some suppliers have done) you get cliff edge like performance. So it's very good in very specific conditions and then poor at anything else (eg. FLO)

Hope that helps

Hambini

[SuperNonAero]

Awesome, cant wait to see both!
Thanks mate

[themidge]

Off topic but...
I think GCN would do wonders for their reputation (amongst us and other cycling media) if they did actual reviews instead of the weird half-review-half-promo things they do at the moment.

[TiCass]

Off topic but...
I think GCN would do wonders for their reputation (amongst us and other cycling media) if they did actual reviews instead of the weird half-review-half-promo things they do at the moment.

The problem with reviews is that they are boring, repetitive and highly subjective.
Just look at the super bike "all-round" category; S-Work Tarmac, Cervelo R5, BMC Team Machine 01... its more or less the same bike. What do you expect to learn with reviews?

[Marin]

I didn't pay them to appear on the show and they didn't pay me to appear on the show.

Sounds like a bad deal!


Here's hoping that your segment doesn't turn into "CAN YOU TEST YOUR AERO WHEELS AT HOME?!" type thing

[tanhalt]

It's not a bad thing that people (in general, not just specific members) question Hambini and ask him about his protocols, methods and data. That's welcomed, even if it becomes frustrating when he answers but they react as he never did.

Perhaps because he hasn't actually answered? Especially not in a clear and concise manner...

It's laughable though that the same people never questioned tests from an online blog, a cycling magazine, the 'Chung method', or a big manufacturer although these are full of missing data, simplistic methods and lacking protocols. They are instantly persuaded for some reason.

What's truly laughable is that you apparently believe what your wrote above. Those things you mention HAVE BEEN and will be questioned all the time. Any "persuasion" comes from others understanding how the data was gathered and analyzed, and then actually some of them repeating the results. In this case, we haven't even see the data gathering setup, not to mention very little of the actual data (and the one example is highly smoothed and shows wild extremes of yaw angle even smoothed, which is unlike any other data we've seen on the subject).

[tanhalt]

Hey Hambini,

Two questions.
When will your gcn segment be online?
When do you expect the new wheels data you have tested and recorded, will be put online?

Cheers

Speaking of GCN, one more to add...how do you square your proclamations of impartiality with the fact that GCN is apparently known (I've heard this from a bike industry journalist) as a "pay to play"-type review site?

I think most of us are a bit bored of this type of remark /reply

I'm happy to hear you think so too...but, I'm a bit perplexed why you didn't say anything about Hambini making remarks like this until after I finally responded for the first time in kind to the stream of these types of remarks/replies from him?

[tanhalt]

I didn't pay them to appear on the show and they didn't pay me to appear on the show.

Sounds like a bad deal!

Don't worry...I'm sure he plugged his bottom brackets for sale and his YouTube channel while he was on there...so it wasn't a total loss

[hambini]

Appearing on GCN was a bit of an eye opener for me. It was staggering how many people go into resourcing that channel and how much effort goes in to making the videos. Much better than my totally unprofessional video camera and orange board at home. It's also really difficult when you have to present with someone who does it daily. It really showed up my flaws.

Don't worry...I'm sure he plugged his bottom brackets for sale and his YouTube channel while he was on there...so it wasn't a total loss

And I have no shame in admitting that I am very proud of my engineering. I made my bottom brackets off my own back and have lots of happy individuals that have been supplied.

All I detect is a hint of jealousy.

Thanks

Hambini

[tanhalt]

All I detect is a hint of jealousy.

Hmmm...you might want to look at the settings on your hypocrisy detector then

Jealousy? Not in the least...I have a great face for radio, as they say

[Matt28NJ]

Jealousy? Not in the least...I have a great face for radio, as they say

Dude. Move on.

[hambini]

Jealousy? Not in the least...I have a great face for radio, as they say

Dude. Move on.

+1

[Imaking20]

+2

Very excited to see the GCN episode!

[themidge]

^Me too! I love it when they get boffins, bike-packers, actually good pros, and other interesting sorts on the show .

[euan]

Speaking of GCN, one more to add...how do you square your proclamations of impartiality with the fact that GCN is apparently known (I've heard this from a bike industry journalist) as a "pay to play"-type review site?

Its in no way a secret. You're reading too much into it.

https://www.asa.org.uk/rulings/wahoo-fi ... a17-1.html