Power Meters Will Become Standard Equipment for Road Cycling
After you have been riding for a few years and you have ridden in a few century rides and feel like |
| Stages Power Meter |
What is a Power Meter?
A power meter provides a snapshot of how you are riding while you are riding. It measures your power output as you ride, in watts. Power is defined as the Force you are applying to the pedals multiplied by your velocity: Power = F x v. Power meters use strain gages to determine the Force applied and your bike computer supplies the velocity for the calculation of Power that your computer displays and records. All power meters are based on this basic principle, no matter the price or the installation location, on the cranks, pedals or chainring.A power meter is more responsive than a heart rate monitor. Power meters will register your increased effort the moment you encounter even a slight rise in the road elevation. You may not even see the rise, but as you maintain speed and cadence, you will see it right away as a power increase. Heart rate monitors will lag behind power meters. Your muscles will increase their power output immediately and will signal your heart to increase blood flow sometime after beginning the increased effort. This instant feedback is important to me. It helps me manage the ride as it is going. On the flats, I keep the power output up to maintain speed and not mentally drift off and just cruise along. On climbs, I keep my power output below a set amount so that I don’t burn matches for no good reason. Overall, you can quickly tell from the power reading whether you are having a good day or not.
The Data You Get
The power meter will provide the average power for a given ride. Average power is the average of all of your power readings, including times that you are coasting. This is a measure of your improvement over the course of a season. You should see your average power rise on the same route as the season progresses.Normalized power is a calculation based on the average power that takes a number of factors into account, including eliminating the coasting time. It is higher than average power and is a more accurate measure of your power output on a ride. I review this number after every ride.
Watts per kilogram is the ratio between your power output and your weight. Raw power is not the best measure of what you can do on the road. Smaller riders need less power to go fast, especially up hills. Larger riders typically are stronger but require more power to go the same speed as smaller riders. This ratio takes weight and power into account. A typical pro rider can sustain 6 Watts/kg, where an average rider who does not compete at all can sustain 2.3 Watts/kg. On Stage 5 of the Amgen Tour of California, the peloton rolled up San Marcos Pass (Highway 154) at 16 miles per hour, a 4-mile climb with 4 to 8% grades. I asked Greg Daniel, of the Axeon Cycling team how much power were they pushing that grade. He said he was pushing 400 watts up that hill.This is toward the end of a 108-mile stage.
Functional Threshold Power (FTP) is the maximum power that you can sustain for one hour. FTP was developed by Andrew Coggan, Ph.D., a road cyclist and exercise physiologist. This figure can be determined through a 60-minute all-out effort, which is pretty intimidating for any cyclist who isn’t paid to suffer like that. The simpler method to go all-out for 20 minutes after a 45-minute warm up. Then take 95% of that number to calculate your FTP. This is an important number for you to know or at least estimate. Without getting into all of the training zones that come with FTP, the simple way to train is to stay at or near your FTP during your training rides to get an increase in your fitness. Stay well below your FTP, say 60%, for a recovery ride. Using the Intensity Factor, IF, makes this easy. It is your Normalized Power divided by your FTP. I have it on the first training screen of my Garmin bike computer. For hard training rides, I want to keep the IF around .8 or above. For recovery rides, I let IF drop to between .6 to .7.
On longer rides, like centuries, I will monitor my speed, power, cadence and heart rate and balance out my effort using these numbers as a guide. For training rides, I’ll focus on speed, power, cadence and IF and not worry about heart rate.
Cost
Power meters are slowly falling in price as more companies are entering the power meter market. A few short years ago, power meters were solely for pro riders with sponsors and big equipment budgets. Now there are power meters below $1000. Still a sizable investment for something that is not directly contributing to making the bike go, like the wheels or groupset.
Major Power Meters
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Name
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Cost
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Installation Location
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$1,800 - $3,700
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Crank
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$2,000 - $3,600
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Rear Wheel Hub
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$1,600
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Crank
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$1,500
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Pedal
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$899
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Left Crank Arm, Power Meter doubles Power to account for both left and right cranks
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$650
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Left Crank Arm, Power Meter doubles Power to account for both left and right cranks
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I ride training rides 2 to 3 times a week after work with a longer ride on Saturday. The training rides are between 9 and 20 miles depending on the amount of sunlight left when I start in the early evening. Generally, that Monday ride is a recovery ride, to loosen up the muscles, with an IF around .7. The rest of the rides of the week, I will keep the IF above .8. I now can sustain speeds that I could not before and hills are becoming easier and easier. I am not turning pro by any means, but challenges are getting more manageable. I was able to complete the tough Santa Barbara Century, with 9,000 feet of climbing, in the middle of the group. The year before, I was nearly the Lanterne Rouge, the Red Lantern, traditionally the last rider to finish a race. So from a cramp filled ride that was such a struggle that I had to cut it short, to a strong ride finished with confidence.
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