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




Post new topic Reply to topic  [ 281 posts ] 
Go to page Previous  1, 2, 3, 4, 5, 6, 7 ... 19  Next
Author Message
PostPosted: Thu Feb 20, 2014 10:45 pm 
Offline

Joined: Tue Jul 18, 2006 5:18 am
Posts: 590
Location: Cambridge, New Zealand
I do a lot of modelling using wind tunnel data, factoring course elevation/direction, equipment weight and rider metrics. I have had very good success relating the models to the real world.

For TT/Tri I look at steady state, solo scenarios (though do have different drafting factors for Tri as cheating is prevalent). For road races I analyse the pinch points - much as I do when coaching athletes - it's all about getting up the crucial hill or having a kick at the finish. Tour have gone with the Tri/TT method (though have alluded to the pinch point effect with cav/goss).

I may have some time later to work with Tours numbers to turn them into more useful info, in the meantime - I wrote this article http://speedtheory.co.nz/tour-de-france ... nt-effect/ about Bakelants stage winning effort - 10m difference over 1.6km on his own (at 53kph) by using an aero advantaged road frame - not enough to mean that he would have lost without - but enough to mean that he wouldn't have had yellow. Which turns it into a very significant difference.

I've analysed a few MAMIL favoured fun rides and the differences in energy usage by having an aero frame in a peloton at 30kph are not huge. But they are there. My personal experience is that riding an aero frame feels like cheating, but it's legal! So why wouldn't I do it?

_________________
http://www.speedtheory.co.nz


Top
 Profile  
 
Posted: Thu Feb 20, 2014 10:45 pm 


Top
  
 
PostPosted: Tue Feb 25, 2014 3:52 pm 
Offline

Joined: Fri Aug 23, 2013 7:39 pm
Posts: 21
I totally agree with tommasini. Just a few percent over 4 hours+ for us mere mortals isn't going to matter. So #aeroiseverything = not if your not a pro. Come to think of it, having a nicely fitted jersey is probably going to matter more.


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 4:37 pm 
Offline

Joined: Mon May 30, 2005 7:13 am
Posts: 1522
mdusink, but what if you wore a well fitting jersey and had an aero frame? why do small margins not matter to cat 4-5 racers, don't crits come down to small margins? Do people like to win less just because its not their job? If you're going to pay $2500-10000 for a new bike, why not get something on the more aero side?

Lets face it, the new S2/S3, AR and Propel advanced all have frameset weights that are not a hinderance, and are a step up in comfort and stiffness over older aero models. Benefit, with little compromise.


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 5:13 pm 
Offline
Shop Wrench
User avatar

Joined: Sat Nov 29, 2008 6:15 am
Posts: 718
I'm surprised by the closeness of the results. I wish they were able to model using a full body mannequin. SI can see a 1-2kmh increase in speed with no increase in power just by rotating my hips forward and bending my elbows a few more degrees. If I leave that position and go onto the hoods, Id be going 4-5kmh slower. I find it hard to believe that my torso position does not affect the aerodynamics of the frame and of the entire mass of me and the bike.

_________________
"Any intelligent fool can make things bigger, more complex, and more violent. It takes a touch of genius -- and a lot of courage -- to move in the opposite direction."


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 5:33 pm 
Offline

Joined: Fri Jan 07, 2011 6:58 am
Posts: 832
Location: 604
Will never buy a cervelo because of rubbish white paper marketin.... errrr I mean data like this. Can't decide if the significance cervelo gives to these results is laughable or insulting our intelligence.


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 5:41 pm 
Offline

Joined: Wed Jan 01, 2014 8:33 pm
Posts: 25
petepeterson wrote:
Will never buy a cervelo because of rubbish white paper marketin.... errrr I mean data like this. Can't decide if the significance cervelo gives to these results is laughable or insulting our intelligence.
http://www.tealsport.com/_upload/showca ... esults.pdf Cross Giant off your list as well. http://www.specialized.com/OA_MEDIA/pdf/Witchcraft.pdf And Specialized.


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 5:44 pm 
Offline
User avatar

Joined: Mon Feb 19, 2007 7:26 am
Posts: 1784
Location: Atlanta, GA, US
That is not a white paper by Cervelo, it is just the results from a recent Tour magazine test. So don't blame Cervelo for just sharing the results from a test where their bikes came out on top.

_________________
My Bikes

My Photoblog


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 5:46 pm 
Offline
User avatar

Joined: Mon Feb 19, 2007 7:26 am
Posts: 1784
Location: Atlanta, GA, US
743power wrote:
I'm surprised by the closeness of the results. I wish they were able to model using a full body mannequin. SI can see a 1-2kmh increase in speed with no increase in power just by rotating my hips forward and bending my elbows a few more degrees. If I leave that position and go onto the hoods, Id be going 4-5kmh slower. I find it hard to believe that my torso position does not affect the aerodynamics of the frame and of the entire mass of me and the bike.


I thought it was mentioned earlier that they indeed used a pedaling mannequin for the test?

_________________
My Bikes

My Photoblog


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 7:00 pm 
Offline

Joined: Fri Aug 31, 2012 6:32 pm
Posts: 159
I think it's funny that so many people here are poopoo-ing a 1% difference between the fastest and slowest frames yet these are the same people who came to this website to save 20g on their saddle. 20g for a light rider with a light bike is only a 0.3% difference up a completely vertical wall.


Top
 Profile  
 
PostPosted: Tue Feb 25, 2014 8:08 pm 
Offline
User avatar

Joined: Wed May 02, 2012 8:33 pm
Posts: 89
Location: Los Angeles, California, USA
fa63 wrote:
I thought it was mentioned earlier that they indeed used a pedaling mannequin for the test?


They only used the bottom half of the dummy.

_________________
Long live the horizontal top tube, standard crankset, and Italian threaded bottom bracket.


Top
 Profile  
 
PostPosted: Wed Feb 26, 2014 2:59 am 
Offline
User avatar

Joined: Sun Oct 24, 2004 1:41 am
Posts: 537
Location: Toronto, Canada
Also all but the giant propel got a zipp vuka sprint bar. This skewed the results as the giant bar is not as aero but is lighter and stiffer. It also hurts less as the rear of the vuka is so sharp if you hit the top of your arm when in the drops you will bruise.


Top
 Profile  
 
PostPosted: Wed Feb 26, 2014 3:48 am 
Offline

Joined: Tue Jun 07, 2005 3:32 pm
Posts: 501
deek wrote:
I think it's funny that so many people here are poopoo-ing a 1% difference between the fastest and slowest frames yet these are the same people who came to this website to save 20g on their saddle. 20g for a light rider with a light bike is only a 0.3% difference up a completely vertical wall.

HA. True.
However: I assume you've used a 6kg bike and a 60kg rider, so is it then 0.03%? I'm no scienticianist :thumbup:


Last edited by User Name on Wed Feb 26, 2014 4:43 am, edited 1 time in total.

Top
 Profile  
 
PostPosted: Wed Feb 26, 2014 4:11 am 
Offline

Joined: Wed Jan 01, 2014 1:40 am
Posts: 22
An aero bike is as aero as an aero bike can be but a person can only be so aero, quintessentially an aero bike is more aero than a person, therefore who would care if a test dummy is utilised in aero testing or not, that is of course unless an aero test dummy was used then one would be quite interested.


Top
 Profile  
 
PostPosted: Wed Feb 26, 2014 4:24 am 
Offline
Moderator
User avatar

Joined: Sat Mar 14, 2009 6:08 am
Posts: 7464
Location: Geeeelong!
mdusink wrote:
So #aeroiseverything = not if your not a pro.

On that reference, Spec's data shows that the difference between a 'bad' helmet (eg: the Prevail) and an aero helmet (eg: the Evade) is not as pronounced for a rider with a low and aero position.

Whereas a rider (read: "if you're not a pro") with a more upright position will actually have a greater benefit. NGNM nailed it, it's a marginal gain that is up to each individual as to whether they buy in to.

Otherwise, deek. Word! :beerchug:

_________________
http://www.nicksquillari.com.au Forum Jedi


Top
 Profile  
 
Posted: Wed Feb 26, 2014 4:24 am 


Top
  
 
PostPosted: Wed Feb 26, 2014 1:32 pm 
Offline

Joined: Fri Aug 27, 2010 4:22 pm
Posts: 91
I think my main concern with NGNM's argument of 'why not' is that's it's not the simple choice of an identical frame with Y/N aero or not. There is usually a penalty in either harshness of ride or (certainly on older aero frames) front end stiffness.

I'd rather ask 'why give up ride quality for a gain that's so small it's barely measurable?'. That said, each to their own and aero frames have improved a lot so the penalty is shrinking.

Deek, damn you for pointing out the obvious! :D


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 281 posts ] 
Go to page Previous  1, 2, 3, 4, 5, 6, 7 ... 19  Next


Who is online

Users browsing this forum: Baidu [Spider], Bing [Bot], EvilEuro, ophiravina and 34 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. Are all the Boardman SLS frames the same?

in Road

BigPoser

3

521

Mon Oct 27, 2014 12:38 pm

Philbar72 View the latest post

There are no new unread posts for this topic. Aluminium Frames/Build

[ Go to page: 1, 2 ]

in Road

digger

17

2001

Wed Jul 16, 2014 8:39 am

theosaurus View the latest post

There are no new unread posts for this topic. XACD Ti frames experience

in Road

Phill P

8

1881

Mon Jun 30, 2014 9:19 pm

dvincere View the latest post

There are no new unread posts for this topic. Women's Carbon Frames

[ Go to page: 1, 2 ]

in Road

Valbrona

22

1196

Tue Oct 21, 2014 2:52 pm

wingguy View the latest post

This topic is locked, you cannot edit posts or make further replies. Sub-$1000 sub-900g Frames?

in Road

PDXWheels

1

574

Mon Aug 18, 2014 11:47 pm

aaric View the latest post


It is currently Sat Dec 20, 2014 12:43 pm

All times are UTC + 1 hour




Advertising   –  FAQ   –  Contact   –  Convert   –  About

© Weight Weenies 2000-2013
hosted by starbike.com


How to get rid of these ads? Just register!


Powered by phpBB