Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

Do smaller wheels provide important Aero advantage?

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

Do smaller wheels provide important Aero advantage?

Old 09-30-12, 04:24 AM
  #1  
Junior Member
Thread Starter
 
Join Date: Aug 2012
Posts: 21
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Do smaller wheels provide important Aero advantage?

Hello, I know that bigger 700c wheels provide higher gain per spin, effectively increasing gear ratio.
But given the same frame, 26" wheels will sit lower than 700c wheels, thus providing lower air resistance (Or does only the difference in wheel size matter here? Not the overall height?).
Is this difference in air resistance insignificant or can it actually be more important then wheel size at some speeds?

Last edited by Skinner; 09-30-12 at 04:43 AM.
Skinner is offline  
Old 09-30-12, 05:00 AM
  #2  
Senior Member
 
AdelaaR's Avatar
 
Join Date: Apr 2010
Location: Vlaamse Ardennen, Belgium
Posts: 3,898
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 3 Times in 3 Posts
Smaller wheels are obviously more aero, but not always feasible ... more importantly ... they aren't allowed by the UCI.
In triathlon people use smaller wheels to gain aero advantage.
AdelaaR is offline  
Old 09-30-12, 05:10 AM
  #3  
Professional Fuss-Budget
 
Bacciagalupe's Avatar
 
Join Date: Aug 2005
Posts: 6,494
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 32 Post(s)
Liked 24 Times in 14 Posts
As a general rule of thumb, smaller wheels are stronger and more aerodynamic, but are more responsive, have more rolling resistance and are less comfortable. The drivetrain will also be slightly lower to the ground.

Gear ratios don't affect speed, it only means you need slightly different gearing.

The tri community went through a spasm of pushing 650 a few years ago, partly due to the aero advantages, but they've pretty much gone back to 700c.

In terms of performance, it's pretty much a wash.
Bacciagalupe is offline  
Old 09-30-12, 07:34 AM
  #4  
Boyd Cycling owner
 
coachboyd's Avatar
 
Join Date: Mar 2011
Posts: 412
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Likes: 0
Liked 3 Times in 1 Post
Originally Posted by AdelaaR
... they aren't allowed by the UCI.
In triathlon people use smaller wheels to gain aero advantage.
Actually if you use two 650 wheels it would be allowed by the UCI, the rule there is that both wheels have to be the same size (ie, you can't run a small front wheel wheel and larger rear one).

Most triathletes now run 700 wheels because they roll better, smaller riders (usually under 5'3" will use 650 because it allows them to get into a more aero position as the handlebars don't have to sit up as high.
coachboyd is offline  
Old 09-30-12, 01:06 PM
  #5  
Senior Member
 
Join Date: Dec 2009
Posts: 4,700
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 5 Times in 4 Posts
There are also pedal/ground clearance issues with smaller wheels.
achoo is offline  
Old 09-30-12, 01:26 PM
  #6  
Senior Member
 
Join Date: Nov 2008
Location: Bay Area, Calif.
Posts: 7,239
Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 659 Post(s)
Likes: 0
Liked 7 Times in 6 Posts
Originally Posted by achoo
There are also pedal/ground clearance issues with smaller wheels.
Not if the frame is designed for that wheel size. My bike with 20" wheels has the same pedal to ground clearance as my 700c bikes.

In addition to smaller wheels having less wind resistance, a smaller front wheel also allows the rider to draft more closely behind another rider in a paceline. But, as already mentioned, there are drawbacks in rolling resistance and ride comfort on rough roads. In comparing rides with my 20" wheeled bike to those with 700c wheels I find both the advantages and disadvantages to be rather minor.
prathmann is offline  
Old 09-30-12, 01:37 PM
  #7  
Administrator
 
Join Date: Feb 2005
Location: Delaware shore
Posts: 13,569

Bikes: Cervelo C5, Guru Photon, Waterford, Specialized CX

Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1102 Post(s)
Liked 2,135 Times in 1,440 Posts
Originally Posted by coachboyd
Most triathletes now run 700 wheels because they roll better, smaller riders (usually under 5'3" will use 650 because it allows them to get into a more aero position as the handlebars don't have to sit up as high.
I used to do lots or tri's and then stopped until recently. The thing that surprised me geting back into the sport is no one, except very short people, use 650 wheels now.
StanSeven is offline  
Old 09-30-12, 04:16 PM
  #8  
Senior Member
 
escarpment's Avatar
 
Join Date: Oct 2009
Location: chicago
Posts: 781

Bikes: cannondale crit 3.0, specialized allez, old giant mtb/hybrid

Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
industry standards... plus the difference in real world physics is negligible.
escarpment is offline  
Old 09-30-12, 04:22 PM
  #9  
Senior Member
 
Join Date: Sep 2009
Location: Utah
Posts: 953
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 1 Time in 1 Post
Originally Posted by StanSeven
I used to do lots or tri's and then stopped until recently. The thing that surprised me geting back into the sport is no one, except very short people, use 650 wheels now.
The availability of good tires and tubes + integrated headsets makes 700c tires the better choice these days.
rpeterson is offline  
Old 09-30-12, 10:14 PM
  #10  
Senior Member
 
Join Date: Dec 2005
Posts: 7,859
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 2 Times in 2 Posts
IMO the only advantage is that you have less rotational mass and the wheel is easier to get it rolling, besides that probably the aero gain part is minimal compared with a 700c wheel.

We got TT track funny bikes back in the day with 650 wheels in the back, 58 chainwheel to compensate for the wheel, the bikes were pretty easy to get them rolling but once in the race personally I did not notice big differences in relation to a regular aero track bike, same stuff.

650 is a good creation of short people so they are able to get some seatpost showing and a descent fit, besides that the % of improvement unless we are talking into super high performance atletes, probably the regular john doe wont even notice the difference.
ultraman6970 is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
FlashBazbo
Road Cycling
340
04-13-17 08:36 AM
Oilsooner
Road Cycling
28
03-13-12 10:36 PM
abstractform20
Road Cycling
290
06-10-11 10:23 PM
goodtimes5
Northern California
41
01-21-10 04:27 PM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.