HOT: Active* forum members generally gain 5% discount at store!
Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Articles FAQ Contact About

Post new topic Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Mon May 10, 2004 3:56 am 

Joined: Thu Apr 15, 2004 12:00 am
Posts: 29
I put up a request for busted rims in the Wanted forum but I have not had any replies. I am intersested in conducting a CFD analysis of rim sections to determine the profile with the least drag and side force. To do this analysis I need to know the exact cross section of the rim. I think this data would be of great interest to the group since there seems to be a lot of interest in different wheel designs.

I was hoping someone had busted rims or knew someone that did so I could obtain sections and measure them. I have tried the manufacturers but they are not interested. If anyone can help please let me know.

Possibly we could try photographs with some kind of reference in the picture. The trick with photographs is getting the curved sections right. If anyone is willing to try this let me know.

Or maybe the wheel owner could carefully take measurements and forward them to me. This will take some experimenting to be sure the data is accurate.

I will post the information as it becomes available. Also, CFD stands for Computational Fluid Dynamics which is the use of powerful software and computers to model real world air flow. Thank you in advance for your help.


 Post subject:
PostPosted: Mon May 10, 2004 9:25 pm 

Joined: Thu Oct 23, 2003 5:18 pm
Posts: 731
Location: Austin
I did aero testing of actual rim samples for development of the Nimble Crosswind. We considered everything from head on 0deg to 22deg yaw. When considering rim only, no hubs or spokes, we found one undisputable fact, greater the yaw, greater the turbulence which was proportional to rim height.

This means the shorter the rim section the more aero considering you cannot guarantee head on winds.

We tested over 30 samples of rims as tall as the zipp 440(top aero dog in ’96) to the smallest box sections. We decided that shorter is better given a variety of wind on any given course. Again, considering a full spectrum of yaw, the Sun M17a was the fastest rim of that time. Interestingly enough, it was also among the lightest.

I really wish I was in possession of that data but it belongs to the company I was working for at the time.

Good luck with your testing.


 Post subject:
Posted: Mon May 10, 2004 9:25 pm 

 Post subject:
PostPosted: Tue May 11, 2004 1:50 am 

Joined: Sun Apr 11, 2004 5:21 pm
Posts: 101
Location: U.S.

Are you just looking for complete rims or can you just live with a small section sawed out of a rim? (much easier to mail to you, eh?).

Per nicrump... will you be doing CFD on the sections at various yaw angles?


 Post subject:
PostPosted: Thu May 13, 2004 11:54 am 
User avatar

Joined: Mon Sep 30, 2002 1:59 am
Posts: 1386
Location: Sydney, Australia
sounds very interesting. Do you know of anywhere I can locate data of wheel drag? The impact of spokes and hub friction is important to the complete package.
WW has some good data on tyres but not on wheels as yet.

How is the research going?


Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

Who is online

Users browsing this forum: 4ibanez, Ashepp, Baidu [Spider], etownfwd, F45, Grill, HammerTime2, MSNbot Media and 42 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Corima Aero S?

in Road




Mon Jul 28, 2014 1:49 am

ichobi View the latest post

There are no new unread posts for this topic. Road Aero Bar Comfort

in Road




Fri Nov 07, 2014 12:14 am

UpFromOne View the latest post

There are no new unread posts for this topic. Easton EC90 Aero 55 tubulars

[ Go to page: 1, 2 ]

in Road




Wed Feb 11, 2015 7:42 pm

simon View the latest post

There are no new unread posts for this topic. TT bike mods for aero+weight

in Road




Sat Jul 26, 2014 10:53 pm

Pokerface07 View the latest post

There are no new unread posts for this topic. What's the lightest aero bike/ frame

in Road




Thu Mar 26, 2015 12:43 am

climbandpunishment View the latest post

It is currently Sun Mar 29, 2015 2:57 pm

All times are UTC + 1 hour

Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by

How to get rid of these ads? Just register!

Powered by phpBB