Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Galleries NEW FAQ Contact About Impressum
It is currently Mon Dec 11, 2017 6:20 pm

All times are UTC+01:00





Post new topic  Reply to topic  [ 292 posts ]  Go to page Previous 114 15 16 17 1820 Next
Author Message
PostPosted: Sun Jul 28, 2013 10:10 pm 
Offline

Joined: Wed Jun 01, 2011 7:53 am
Posts: 699
Yes.


Top
   
Posted: Sun Jul 28, 2013 10:10 pm 


Top
   
 
PostPosted: Sun Jul 28, 2013 11:02 pm 
Offline

Joined: Tue Nov 11, 2003 9:47 pm
Posts: 2196
Location: Santa Cruz, California, USA
Maybe we could get a real engineer like Damon to weigh (heh) in.

I have seen claims (mostly in the press) that a bike that is "too light" handles poorly on descents, but I don't believe that. Modern bikes, even very light ones, are still pretty stiff compared to older frames. Back in the day I raced a Vitus 979, a far flexier frame than anything sold today. It descended fine for me, and for the large part of the pro peloton who used them, often painted to look like sponsor's bikes. To handle poorly on descents it'd have to be considerably flexier than the Vitus. No one's going to make that.

Straight line speed on descents is affected far more by aerodynamics than by weight. I expect that even mildly aero frames like the Rca are faster down non technical descents than their heavier but less aero predecessors like my R3SL.


Top
   
PostPosted: Sun Jul 28, 2013 11:51 pm 
Offline

Joined: Tue Jan 11, 2005 11:40 pm
Posts: 863
Location: Eire
Light, stiff, aero - impossible to discuss ultimate speed without considering all three.

However, what I would like to see discussed in more detail is the degree to which limitations on traction are now the key issue.

In summary, is mechanical grip from the bike tyre now the biggest limitation in point to point speed over hills?; given that aerodynamics of wheels and frames and (increasingly) braking performance have significantly outpaced tyre development

_________________
Not everything that counts can be counted. Not everything that can be counted counts.


Top
   
PostPosted: Sun Jul 28, 2013 11:55 pm 
Offline
User avatar

Joined: Fri Feb 11, 2011 3:04 am
Posts: 2693
Location: Mississippi
From what I have heard/read hydraulic brakes are beginning to address that issue.


Sent from my iPhone using Tapatalk 2

_________________
Mosaic RS-1
http://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=138478

Cielo by Chris King Cross Racer
http://weightweenies.starbike.com/forum/viewtopic.php?f=10&t=134376


Top
   
PostPosted: Mon Jul 29, 2013 12:33 am 
Offline
User avatar

Joined: Sat Mar 14, 2009 6:08 am
Posts: 8408
Location: Geelong
DamonRinard wrote:
There is a thread with this same title "Is lighter/better bike really FASTER?" with only two posts, which is apparently locked. Just curious, why might this thread be locked?

As an engineer and a weight weenie who is very interested in going faster, I was looking forward to the other forum members' replies.

Hi.

There is a thread for it :unbelievable: which was linked not more than one line below the OP.

It was in relation to wheels, hence the link.


There is also a thread specifically in relation to your question, again in the Road Index (and I have merged this thread with that).

_________________
VeloKicks
The Gram
The Men of Steel


Top
   
PostPosted: Mon Jul 29, 2013 12:35 am 
Offline

Joined: Sun Sep 27, 2009 9:54 am
Posts: 359
Location: Australia
Quote:
is mechanical grip from the bike tyre now the biggest limitation in point to point speed over hills?


I doubt it

_________________
2012 Scott Foil Premium


Top
   
PostPosted: Mon Jul 29, 2013 12:48 am 
Offline
in the industry

Joined: Fri Apr 29, 2011 8:32 pm
Posts: 182
Tinea Pedis wrote:
I have merged this thread


I understand now, thanks for explaining. :-)

_________________
Damon Rinard
Engineering Manager, Road Bikes
Cycling Sports Group, Cannondale
Ex-Kestrel, ex-Velomax, ex-Trek, ex-Cervelo


Top
   
PostPosted: Mon Oct 28, 2013 11:18 pm 
Offline

Joined: Mon Oct 28, 2013 11:08 pm
Posts: 33
So I'm trying to decide between an Aero and Traditional road bike and noticed that Aeros tend to have a much higher "stack" in their geometry. So I'm both wondering what's the point and also if there's any whitepapers comparing them in the wind tunnel with a dummy rider.

If it turns out the drag is nearly identical due to rider position, I'd much rather have the lighter Traditional road bike for obvious reasons.


Top
   
PostPosted: Tue Oct 29, 2013 6:01 pm 
Offline

Joined: Fri Jul 06, 2012 9:41 pm
Posts: 16
So this is hardly scientific, but if I had to guess - stack is higher on some aero frames because it actually does confer an aero advantage. Outside of stem-slamming for the sake of stem slamming, most people run spacers. So, by making the stack higher, it's possible to engineer a frame that is as aero as possible, eliminating the spacers in favor of an aerodynamic shape. I vaguely remember hearing something about this when Cervelo released the S5.

Also, don't forget that it's not JUST the head tube that imparts the aero difference...


Sent from my iPhone using Tapatalk


Top
   
PostPosted: Wed Oct 30, 2013 4:41 am 
Offline
User avatar

Joined: Wed Oct 31, 2007 10:32 pm
Posts: 8506
Location: Los Feliz, Los Angeles, California
^Correct.

It is also true that a tuck on the top of the hoods (Cancellara style) is as aero as being in the drops if you can get your body low enough.
http://gerard.cc/2011/07/29/body-vs-bar-1/
http://gerard.cc/2011/08/02/body-vs-bar-2/

_________________
Exp001 || Other projects in the works.


Top
   
PostPosted: Wed Oct 30, 2013 2:36 pm 
Offline

Joined: Thu Mar 20, 2008 3:03 am
Posts: 713
Location: nyc
johnsaysthisnow wrote:
So this is hardly scientific, but if I had to guess - stack is higher on some aero frames because it actually does confer an aero advantage. Outside of stem-slamming for the sake of stem slamming, most people run spacers. So, by making the stack higher, it's possible to engineer a frame that is as aero as possible, eliminating the spacers in favor of an aerodynamic shape. I vaguely remember hearing something about this when Cervelo released the S5.

Also, don't forget that it's not JUST the head tube that imparts the aero difference...


Sent from my iPhone using Tapatalk




Exactly correct.

The issue I have is most "aero" modeling of wheels and frames is done at speeds of 25-30 mph or more which seems pro-level fast and losses much of its relevance for anyone averaging speeds slower than that, so its great for the top 5 pct and the rest of us when we get to those speeds but if you average 20-25 over distance it seems the aerodynamics are meaningless, so then weight becomes a bigger factor in terms of hauling and power output. That was my biggest issues with a frame like the BMC TMR01 which I really liked but in the end, felt that they skewed towards stiffness and aero over weight in a way that would not be of much use to me and my decidedly less-than-pro abilities.

_________________
My wallet is the lightest thing on my bike.


Top
   
PostPosted: Wed Oct 30, 2013 5:01 pm 
Offline
User avatar

Joined: Sat Dec 06, 2008 10:14 am
Posts: 1062
Location: Sweden
Aren't the super tall head tubes actually due to 95% of the customers being lard ass dentists/lawyers/etc. Seriously, if we're talking Specialized, Cervélo, and the likes. This is what I see on the roads on grouprides and the people I meet (pass...) on solo rides, in the case of aero frames.

Ofcourse everyone riding big name aero bikes are neither unfit nor dentists, I'm not looking to hurt anyone's feelings, but the average super dedicated cyclists on WW really doesn't represent what the average real world customer looks like. Most aero road bike buyers are middle-aged (and then some...), unfit by serious cyclist terms, holds down a well paying occupation, and are dead slow on a bike...

Cervélo and Specialized can't ofcourse say this in an ad blurb, but reality is likely they are not making bikes for cyclists - they are making bikes for customers. These are the primary customers.

_________________

The Shivenge


Top
   
PostPosted: Wed Oct 30, 2013 5:08 pm 
Offline

Joined: Thu Mar 20, 2008 3:03 am
Posts: 713
Location: nyc
I think doe frames were designed for this types of riders like the cervelo Rs was, but it also makes sense that rider positioning has evolved over time and a more comfortable, slightly more upright position is beneficial for most, it also helps to not be too stretched out as ar as power transfer on a bike, so taller head tubes are stiffer and potentially can be designed more aerodynamically than spacers. Riders who stack lots of spacer on top of taller head tubes are probably riding the wrong type of frame. At least thats my understanding.

_________________
My wallet is the lightest thing on my bike.


Top
   
PostPosted: Wed Oct 30, 2013 6:03 pm 
Offline
User avatar

Joined: Fri Sep 15, 2006 6:02 am
Posts: 3757
Location: On the bike
gitsome wrote:

The issue I have is most "aero" modeling of wheels and frames is done at speeds of 25-30 mph or more which seems pro-level fast and losses much of its relevance for anyone averaging speeds slower than that, so its great for the top 5 pct and the rest of us when we get to those speeds but if you average 20-25 over distance it seems the aerodynamics are meaningless, so then weight becomes a bigger factor in terms of hauling and power output. That was my biggest issues with a frame like the BMC TMR01 which I really liked but in the end, felt that they skewed towards stiffness and aero over weight in a way that would not be of much use to me and my decidedly less-than-pro abilities.


Why does aerodynamics go out the door when you are doing 20-25mph instead of 25-30mph? :wink:

As Zipp and some other guys have shown, if you are a slower rider (20-25mph) you are out on the course longer so you actually benefit more in the amount of time saved vs running something not as aero.

_________________
"Marginal gains are the only gains when all that's left to gain is in the margins."


Top
   
PostPosted: Wed Oct 30, 2013 6:14 pm 
Offline

Joined: Tue Sep 20, 2011 12:54 pm
Posts: 395
Location: Haines, AK - Temporarily
gitsome wrote:
if you average 20-25 over distance it seems the aerodynamics are meaningless
Tell that to all of the Tri/Iron Man guys rolling around at 24 mph on their bikes.


Top
   
Posted: Wed Oct 30, 2013 6:14 pm 


Top
   
 
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 292 posts ]  Go to page Previous 114 15 16 17 1820 Next

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Aero bars on non aero race bike

[ Go to page: 1 2 ]

in Road

gurk700

16

3477

Sat Mar 18, 2017 6:32 pm

kode54 View the latest post

There are no new unread posts for this topic. Light Aero bikes

in Road

djw52

2

700

Sun Sep 10, 2017 10:27 am

TobinHatesYou View the latest post

There are no new unread posts for this topic. Attachment(s) Light options for aero bikes?

in Road

mariovalentim

5

678

Thu Jun 08, 2017 6:59 am

jekyll man View the latest post

There are no new unread posts for this topic. Attachment(s) ICAN A8 Aero frame

in Road

sivan

1

653

Mon Aug 28, 2017 5:41 pm

bilwit View the latest post

There are no new unread posts for this topic. Factor One Aero bike. Anyone?

in Road

Noctiluxx

2

857

Mon Aug 14, 2017 2:55 pm

Noctiluxx View the latest post


All times are UTC+01:00


Who is online

Users browsing this forum: Chris3g, coriordan, hidefguy, KLabs, oldnslow2, oreoboreo, Pajjy and 46 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:  
Powered by phpBB® Forum Software © phpBB Limited