Is there any benefit to drafting uphill? Does anyone know when steepness of uphill and/or decreased speed negate the affects of drafting?
Drafting uphill
Fri, 09/08/2006 - 7:04am
Fri, 09/08/2006 - 7:14am
#1
Dreafting is used to overcome air resistance, which increases exponetially with speed.
Uphill is a fight against the resistance of gravity.
The steeper the hill, the slower the ride ... and the less importance of drafting. The power-to-weight ratio becomes the main factor.
I see the aerodynamic benefits of drafting starting at about 15 mph, but even that is small. Drafting is good uphill more as a pace-setting mechanism - going 12 mph uphill but staying on that wheel in front of you.
Fri, 09/08/2006 - 8:05am
#2
Additionally
Good post. Adding to it, another variable is headwind.
For instance, during the 2004 Whiteface race (8 mile climb, 8% average grade), there was a stiff headwind. It was a 10mph head wind, if I recall correctly.
For those who drafted, as I witnessed, and having done exhaustive statisically analysis, within that cohort and comparing it to race data from other years, those who drafted, benefited by shaving their time by about 3 minutes on average.
Fri, 09/08/2006 - 8:49am
#3
10 + 10 = 20.
If the rider is doing 10 mph up the hill, the combined wind speed makes drafting very benefitial. That is not even considering the pacing effect...
No wonder the riders who draft goes faster.
Fri, 09/08/2006 - 9:11am
#4
True, but...
..if one is riding 10 mph up Whiteface mountain, that person will find very little, or more likely, no company to form a draft. :-)
Fri, 09/08/2006 - 12:06pm
#5
Mm?
"How come?
""Average grade of 8%"". So some sections are not even 8%. Granted, the steeper section will be slower but the rest should be faster than 10 mph. These aren't exactly the B riders we're talking about... This is a RACE, after all. What's the ""average"" finish time for the 8 mile?
"
Fri, 09/08/2006 - 12:35pm
#6
Out of 217 finishers this year only 45 were under an hour, so all the rest had an average speed of less than 8 MPH.
Fri, 09/08/2006 - 1:57pm
#7
Drafting
"Ralph, I believe there is no difference between drafting uphill or downhill. It's all relative velocity. To answer your question drafting is very beneficial for energy conservation and increased relative speed.
Angle of inclination doesn't have much to do with drafting except for the effects it causes on true and apparent wind. Aside from that it's apples and oranges.
Here are a few interesting links:
Wind Resistance
Wind Load
Apparent Wind
Wind Calculator
"
Fri, 09/08/2006 - 7:26pm
#8
Drafting
Yes, the drafting effect is velocity dependent. For example, at slow speeds drafting may only provide a 20% energy reduction (or less if very slow), while at high speeds this could approach 40%.
In addition, the number of riders behind the lead ride also has an effect upon the front rider's draft coefficient.
Fri, 09/08/2006 - 3:25pm
#9
Whiteface - 10 & 10
10 mph average speed at Whiteface would equate to about a finish time slightly less than 45 minutes (the actual race distance is 7.9 miles). The fastest time ever is 45:02. This was ridden in ideal conditions (e.g. no significant wind). The 2nd fastest official time coming in at 47 minutes and change.
Fri, 09/08/2006 - 6:00pm
#10
Whiteface Record Time
The record was set by a professional triathlete possessing a perfect climber's build...
Since climbing Whiteface and Alpe d'Huez take about the same time, 45 minutes is not a bad time...
Fri, 09/08/2006 - 12:30pm
#11
more psychological...
...remember when lance attacked on the big climbs...he dispatched his fastest/strongest climbers to take the lead and charge the pace with him on thier wheel. easier to climb if you're watching a good climber in front of you.
don
Fri, 09/08/2006 - 2:14pm
#12
There absolutely is an advantage for the person drafting.
Speed needs to be below 10MPH for it not to be noticeable.
That said, climbing is about fighting gravity, if you ride correctly and smart you can open very big gaps in very little distance. So, if you're in a race, it makes total sense to forgo any drafting and simply attack.
