One of the cyclists asked if I was having difficulty keeping up with Louis' fast pace, and I said it wasn't a problem.
As every cyclist knows, its easier to ride fast when in a group, and we've been working on a way to help cyclists understand (and quantify) why that is so. Here is something new we've developed that explains it. I will use my ride file from yesterday to show it off!
1) This is my ride file from yesterday, showing power and bike speed vs distance. This is exactly the information you'd see on any conventional power meter. Power data is in green, and bike speed data is in white:
- Power Speed.png (76.96 KiB) Viewed 28295 times
3) Looking at the graph it would be very nice to know: where was I riding solo, where was I in the group, and what specific effect did the group riding have on my bike speed?
Using the iBike's wind sensor, it's very easy to tell when I am riding in the group, because whenever I am in the draft, my wind speed (in blue) is much less than my bike speed; whenever I run solo, wind speed is almost the same as bike speed:
- Power Speed Wind.png (76.6 KiB) Viewed 28267 times
At the very beginning of yesterday's ride I was riding south, and the group was headed north on the same road. We passed by each other at mile 0.9; I turned around and rode fast to catch up.
I worked really hard to catch the group between miles 0.9 and 2.0 (watts are very high for me, around 350W). My bike speed was pretty high during my chase, too: I was going about 25 mph. At mile 2, I picked up the group and recovered for the next 3 miles. Our group stopped at the park at mile 5. We then turned around and headed home.
During the return trip, I rode in the back of the pack all of the time (the low wind speed looks like blue "icicles" hanging off of white bike speed). Bike speed was higher on the return trip, and increased continuously as Louis picked up the pace. Notice that at mile 9, Louis picks up the pace to 24+ mph.
At mile 12.5, dropped off the ride, turned around and rode home solo (I needed to get back to work). Once I started riding solo again, my wind speed was about the same as bike speed; the "icicles" are gone.
4) In any group ride (or in any racing peloton) the cyclists who are working really hard are the guys in the front, and the cyclists in the pack are working much less, even though they are traveling at the same speed. You can see this in my ride file: between miles 8 and 10, I was able to maintain the 24 mph pace because I was in the draft of the riders ahead of me (note that, when riding solo at the beginning of the ride, I was able to sustain a 24 mph pace for less than 1/2 mile!).
What the peloton does is push the air column ahead for the cyclists who are riding in the pack. So, when the guys in front were seeing opposing headwinds of 24 mph+, in the pack I was seeing an opposing wind speed as low as 10 mph. It takes a lot less effort to pedal against a 10 mph wind! This illustrates a principle most cyclists know, at least intuitively: when drafting, even with much less power, it's easy to go fast. For example, when riding solo around mile 1, it took me 350W to travel 24 mph. At mile 8.5, traveling in the pack at 24 mph, I was using only about 220W...
5) We have figured out that we can combine the unique sensor measurements of the iBike to quantify the speed benefit of the drafting effect. What we wanted was a number that would express, in a common-sense way, the quantitative effect of wind speed on bike speed.
Note that power measurement, per-se, does not quantify the effects of drafting. How much power the rider expends in the draft is highly dependent on the amount of the drafting, which varies according to cyclist position in the peloton, CdA, bike speed, and ambient wind. DFPM power measurement has no clue about the wind.
Bike speed alone doesn't do it. For example, at the beginning of the ride, while riding solo, when my bike speed was 20 mph the opposing wind speed was also about 20 mph. It takes a fair amount of pedal power to push against a 20 mph wind. However, between miles 3 and 12 my bike speed was still 20 mph +, but the riders ahead of me were pushing the air. So, I was going the same bike speed, but using much less power.
And, of course, wind speed measurements by themselves aren't revealing.
6) What we have developed is a measurement that ties ambient wind speed, bike speed, and drafting effects together.
We call it "Effort Speed".
"Effort Speed" is like conventional "bike speed" in that it provides a quantitative measure of how fast the cyclist moving at every point of a bike ride. However, Effort Speed surgically removes all drafting benefits that help riders in the pack, and compensates for headwind penalties suffered by riders at the front of the pack.
Effort Speed reports, in mph (or kph) how fast the cyclist would travel at each instant of the ride, given the level of bike power applied by the cyclist, and without the benefit of tailwind, or penalty of headwind.
Note that, over the course of a ride, the average bike speed of each rider in the group is equal (it better be!). However, there will be HUGE differences in the Effort Speed of these same riders, depending on how hard they ride and how often they lead the group.
In a very quantifiable manner, therefore, Effort Speed "levels the playing field" of every rider in the peloton.
So, in a group ride, the rider with the highest Effort Speed has worked harder on the flats than any other rider in the group.
7) Here, then, using my iBike data is a plot of bike speed (white) and "Effort Speed" (red), for my ride of yesterday. The white "bike speed" curve is identical to the graphs above; the Effort Speed measurement in red is based on power, bike speed, and wind speed:
- Effort Speed.png (45.46 KiB) Viewed 28263 times
The Garneau group was riding in the opposite direction and passed me at mile 0.9. I turned around and rode hard to catch the group. Note that my bike and Effort Speed to catch the group was as high as 26 mph. A solo speed of 26 mph is very fast for me and isn't something I can sustain for very long.
At mile 2, I picked up the group (the blue icicles appear in the bike/wind data). My bike speed then was about 18 mph, but my effort speed dropped to around 14 mph--a cycling speed that is LOAFING!
We stopped at mile 5 for a break, then started heading back south. On the return trip I stayed in the back of the group. The bike speed pace (white) steadily increased, but even though I was traveling at 20 mph+, my Effort Speed is a slacker level of 15 mph-18 mph--again, a loafing-along pace!
Between miles 11 and 12, Louis picked up the pace and the bike speed increased around 24 mph--pretty fast for most solo cyclists. However, my Effort Speed was less than 19 mph--nothing worth bragging about.
When I broke off from the group at mile 12.5 to go home, my bike speed and Effort Speed once again became the same (I lost the benefit of the peloton's tailwind). And even though I slowed down from 24 mph to around 18 mph, my watts show that I was working just as hard as I was when zooming along with the group!
In my solo training rides, on this exact same route, I generally maintain a bike speed of 21 mph. So, while riding with the group, even though my bike speed in this group ride was much faster than my usual solo speed, my Effort Speed shows that I actually was biking slower than I go when riding solo on the same route!
9) "Effort Speed" has many interesting implications:
-Effort Speed quantifies and provides an objective and more realistic measure of the cyclist's overall biking effort, by eliminating the benefits and penalties of wind.
-Effort Speed gives quantifiable credit to the cyclists who stay at the front of the peloton. Think of it this way: even though my average bike speed was the same as Louis', because he was consistently at the front of the pack, his Effort Speed was much higher. My Effort Speed was around 16.5 mph; his was 22 mph+
-So, Effort Speed levels the playing field for the cyclists participating in group rides. All bike speeds aren't created equal...
-Effort Speed also provides an extremely interesting metric for racers. The racer with the highest average "Effort Speed" racer is the cyclist who works the hardest and takes the most turns at the head of the peloton. The racer with the highest Effort Speed is an extremely strong cyclist, perhaps even the best overall cyclist for that day, even though he is almost NEVER the guy who crosses the finish line first...
-Effort Speed allows any cyclist to understand the advantages (and disadvantages) of group riding situations
-Effort Speed allows a solo cyclist to quantify the day-to-day effect of ambient wind on an established training route, making it possible to compare training rides where wind conditions are considerably different
-Effort Speed allows a cyclist to compare the relative benefits of riding a bike route with a group, or riding that same route solo
This is a new concept and, admittedly, is a lot to absorb. We look forward to your comments!
Looks like very valuable info. from what you've shown us in this post 
