Hi MTM,
Very insightful thinking.
Of course, you're familiar with Col de la Tipping Point, a.k.a. Weight versus Aero on our web site. http://www.cervelo.com/.../weight-vs-aero.html
Riding alone, aero is better for every rider on every road, until the up hill is so steep the speed drops enough so that a lighter bike is the same speed as a heavier aero bike.
Then there's also "Aero in the Peloton," here: http://www.cervelo.com/...-in-the-peloton.html
As you mention, the aero benefit decreases (but doesn't vanish) when riding in a group. Even when drafting, aero drag is still the biggest consumer of your power. Until a very steep climb...
Which brings us to your insight: the best bike for a hilly course might be different, depending on rider profiles. For example, I love a fast echelon on rolling terrain, but my colleague David hated them. One day we were rotating beautifully, I was so happy I said "David, don't you just love this?" but he answered "NO! I can't wait 'till we get to the hill, so I can rest!" I was shocked, and finally realized not every rider experienced the course the same way I did. David didn't need a light bike; he needed an aero bike. So consider your strengths and weaknesses - if your critical moment in the race is on the climb, look closely at the math for that section: gradient, weight and aero differences, etc. and decide if the light bike might serve you better. But if, like David, your critical moment is on flat or rolling terrain, then probably the aero bike will help you race better overall.
It's this kind of thinking that makes a good pro team choose different Cervelos for different riders and different events. Team Garmin-Sharp's sports scientist Robby Ketchell wrote about that on our web site here:
http://www.cervelo.com/...-robby-ketchell.html
For your nationals course, the 7% grade is within the range of tipping points (5 to 8%), where the aero bike and light bike are often close in speed. But as you mention, that's for solo riding. In a group, during hard uphill attacks, power and speed are higher, which makes aero more important than during steady solo climbing, extending the tipping point to higher grades, about 1-2% steeper depending on rider weight and power. Assuming rider body types typical at a nationals level race, I'd choose the aero bike, even based only on the up hill and not considering the rest of the course.
You also asked about accelerating out of corners. Corners are exited at speed, so the expected faster acceleration of the light bike is actually a myth; in fact the aero bike accelerates faster than the light bike. (Only from a standing start is the aero bike slower, and then only for the first few pedal strokes, after which it catches and passes the light bike.)
Cheers,
Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
Very insightful thinking.
Of course, you're familiar with Col de la Tipping Point, a.k.a. Weight versus Aero on our web site. http://www.cervelo.com/.../weight-vs-aero.html
Riding alone, aero is better for every rider on every road, until the up hill is so steep the speed drops enough so that a lighter bike is the same speed as a heavier aero bike.
Then there's also "Aero in the Peloton," here: http://www.cervelo.com/...-in-the-peloton.html
As you mention, the aero benefit decreases (but doesn't vanish) when riding in a group. Even when drafting, aero drag is still the biggest consumer of your power. Until a very steep climb...
Which brings us to your insight: the best bike for a hilly course might be different, depending on rider profiles. For example, I love a fast echelon on rolling terrain, but my colleague David hated them. One day we were rotating beautifully, I was so happy I said "David, don't you just love this?" but he answered "NO! I can't wait 'till we get to the hill, so I can rest!" I was shocked, and finally realized not every rider experienced the course the same way I did. David didn't need a light bike; he needed an aero bike. So consider your strengths and weaknesses - if your critical moment in the race is on the climb, look closely at the math for that section: gradient, weight and aero differences, etc. and decide if the light bike might serve you better. But if, like David, your critical moment is on flat or rolling terrain, then probably the aero bike will help you race better overall.
It's this kind of thinking that makes a good pro team choose different Cervelos for different riders and different events. Team Garmin-Sharp's sports scientist Robby Ketchell wrote about that on our web site here:
http://www.cervelo.com/...-robby-ketchell.html
For your nationals course, the 7% grade is within the range of tipping points (5 to 8%), where the aero bike and light bike are often close in speed. But as you mention, that's for solo riding. In a group, during hard uphill attacks, power and speed are higher, which makes aero more important than during steady solo climbing, extending the tipping point to higher grades, about 1-2% steeper depending on rider weight and power. Assuming rider body types typical at a nationals level race, I'd choose the aero bike, even based only on the up hill and not considering the rest of the course.
You also asked about accelerating out of corners. Corners are exited at speed, so the expected faster acceleration of the light bike is actually a myth; in fact the aero bike accelerates faster than the light bike. (Only from a standing start is the aero bike slower, and then only for the first few pedal strokes, after which it catches and passes the light bike.)
Cheers,
Damon Rinard
Engineering Manager,
CSG Road Engineering Department
Cannondale & GT Bicycles
(ex-Cervelo, ex-Trek, ex-Velomax, ex-Kestrel)
Last edited by:
damon_rinard: Jul 22, 14 11:51