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iBike: Taking a Look - Part 2by The Bike Messenger
Published: 04/10/2007iBike: Taking a Look - Part 2
My Power Background
I've been training with power for several years, but only when indoors in the winter. In the past, this hasn't been an issue, because I looked at power as more of a way to be sure I was putting out enough power in the off season...to just keep some percentage of strength. Since I was a 16 year old junior back in the late 80's, I always saw road time as the ONLY way to REALLY get in shape. Unfortunately, power meters were unheard of - and power output on the bike in general was barely an emerging topic.
After having used a CompuTrainer for several years to measure power indoors, my views shifted from merely trying to maintain a minimal level of fitness during the winter, to thinking that perhaps I could improve particular aspects of my game by utilizing watts. I know this is an obvious leap, but you have to realize I always saw the road as the only way to get in shape - with or without a power meter.
Even though I used power extensively for a few years during the winter, I never really cared that I didn't have it out on the road. This was silly because my training during the winter was actually more focused than it was once I got out on the road. Sure, I'd use a heartrate monitor now and again, and it helps...but overall, I was un-focused once I was off the trainer and out the door.
So there you have it, the background to what you are about to read. I've been contemplating buying a power meter for quite some time, but the price always scared me. So did the constant stories of people sending their PowerTaps back to the manufacturer to have it "serviced" (read: fixed). I have enough headaches with flat tires, broken spokes, mis-shifting derrailleurs, etc. - I didn't need one more thing to add to the pile.
Then, the nice folks over at iBike sent me an iBike Pro to use. So am I biased? Sure, they hooked me up with a cool tool. Will I tell you the real deal? You betcha. It's not perfect - I'll guarantee you that, but from what I've seen so far, it's well worth it's price. Contrary to some reports, it is much more than a fancy "toy". It's immediate feedback in 95% of situations - making it a fantastic training tool.
The Data
I dragged my buddy "Turbo" out for a 55 mile hill training ride and took the iBike with me. We did some great climbs (we have plenty here in Central New York) - including the one depicted in the chart below - Holmes Rd.
Holmes
Holmes Rd. climbs 355 feet in only .6 miles. For this distance it averages 11% gradient. Maximum gradient is about 16-17%. So yeah, it's an out of the saddle, cranking the bike effort. Check out what it looked like:
Let's look at the numbered items in the chart above.
#1: This effort was the bottom part of the climb. We had been descending for quite some time, so I was ready to lay down some power. I was averaging somewhere around 450 watts for the first minute. This was 100% out of the saddle. The effort definitely felt like 450 watts as it was well into anaerobia. At the end of this effort, you see a 15 second dip down almost to 100 watts. Holmes crosses another road at this point, so it was me making sure there was no traffic coming.
#2: This section is the bottom of the climb after you cross the cross road. It starts you off with a brutal 13%+ gradient immediately. My average through this section was 380 watts for about a minute and a half. Then I think I got tired...but that whole minute and a half was done between 12% and 14% gradient. Holmes isn't a nice road.
#3: Ok, spending a bunch of time way over my threshold started to take it's toll and you can see my wattage drop back down to the 250 watt range. I did this for about 30 seconds when the road "leveled off" to 9% (mildest gradient on the climb).
#4: As I started to recover slightly, as well as hit the steeper slopes once again, the power steadily increased back up to a peak of 465 watts. Slowly, my power creeped back down...
#5: You can see my power creeping down to this point where I am back down to 300 watts.
#6: Final push to the top. I peak out at just about 500 watts.
iBike Observations
The chart you see here is the chart created by the software that comes with the iBike. I love the fact that you can find exactly where the hills are by the elevation profile. I don't believe even a PowerTap does this. In fact, if I look at the whole ride, I can see each hill that I did as a profile laid right over the top of the power chart.
Other Chart Options
The above example of Holmes Rd. is only showing elevation and power (I did this for clarity sake). Other data on the chart that can be turned on and off on the iBike software include: Bike Speed, Wind Speed, Readings, Hill Slope (in addition to the Elevation and Watts that are shown in the graph). Obviously, the power is probably the most important of them all, as this is a direct measurement of your effort. Let's look at each function that can be depicted on the graph.
Power
The main reason most people buy a power meter to begin with. Power is a fantastic way to track current fitness, intervals, etc.
Elevation
On the Chart: Awesome feature. Let's you look at a whole ride and see each hill that was completed. This ride looked like a mini-Tour de France mountain stage (ok, not quite).
Elevation Note: One small anomoly that I noticed with elevation. I think it's slightly out of synch with the power. Look at the chart above again. You'll notice that the heavy application of power starts before the hill slope and ends well before the hill ends. Not really a big deal as it's very easy to interpolate the data. Perhaps this will be addressed in future software or firmware updates. Regardless, the elevation feature is great.
On the BikeYou can even tell during the ride how many feet you have climbed to that point in real-time!
Hill Slope
On the Chart: Basically, we're talking percentage gradient. When this is turned on, you can see where the steepest grades are in a climb.
On the bike:While you're on the bike, if you have "hill mode" turned on, the iBike will flash between speed and gradient in one of it's displays. So essentially, in real-time, you can view your speed, the gradient that you are currently on, your wattage, acceleration AND cadence. Without hitting a button! If you can't pace yourself correctly with that much data, you might as well stop trying. I have found that I tend to get focused on watts and speed, with the occassional glance at cadence.
Bike Speed
Uhhh, pretty self-explanatory. Average and maximum speed are provided both on the chart and in the on-bike display.
Wind Speed
Yep - it will even tell you what the wind speed was. I'm not sure - and I'm not going to look in the manual - but I think basically if it's showing a higher wind speed than bike speed, you've got a headwind. If the wind speed is lower than the bike speed, you've got a tailwind. Haven't decided how accurate this is. I'm assuming relatively accurate as it's probably used in the calculation of watts.
Readings
This one is really interesting. It gives you a bar chart and a pie chart showing you what percentage of your total power output was used to overcome:
- Aerodynamic Drag (1%)
- Acceleration (21%)
- Friction (1%)
- Hill (77%)
The pie chart shows percentages, and the bar chart shows actual wattages based on these percentages. This is for one second of reading. At that moment, I was putting out 546 watts total. 419 of those watts, representing 77% of the total, were going toward overcoming gravity (hey, I'm a big guy). I was on a 15.4% slope. Since my speed was ultra-low, aerodynamic drag is negligible at only 3 watts - I was only doing like 6 or 7 mph. Friction is accounting for 8 watts (although I would guess this one was actually higher...). 117 watts was being applied to acceleration (this was the very last pedal stroke before laying off and dropping back down to 250 watts).
That's the end of PART 2 of taking a look at the iBike...in the next installment I'll continue looking at some charts. And wrap up my review of the iBike.
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