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iBike vs. Power tap

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Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

iBike vs. Power tap

Old 04-23-15, 04:21 PM
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Originally Posted by Dunbar
Are you going to be training on (650c) tubular tires? The main benefit of power is training and most of us train on clinchers. I would personally get a new alloy rear G3 clincher wheel for $800-900 and run a disc cover for races.
I installed a tubular tire on my zipp 400 last night (without gluing) and it was just as easy, if not easier than a clincher. Ive got a set of continental sprinter tubular tires ready and have 2 used cheapo spares coming from a friend. Only problem I see is having to spend more money on repairing flats, and I'll have to pump them up more often. I've been lucky with the lack of flats throught my cycling days and I'm praying it's gonna stay that way.
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Old 04-23-15, 06:21 PM
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Originally Posted by yankeefan
The devised a neat system that allows me to use the numbers for in-ride pacing; its not foolproof, but more informative than HR zones (especially when caffeine/fatigue/weather/etc starts messing with HR).

First of all you have to use 30s AVG power. Instantaneous, 3s, 5s, & 10s power will fluctuate too much for you to hold a certain number of "watts". Also, 30s avgs smooths over sharp spikes/falls in HR due to a stimulant or rapidly changing core temp.

Do the FTP test (30 min time trial). It won't translate neatly into the standard power zones, but it'll give you an idea of what numbers will pop up when you're going full gas for an extended period. This is how PowerCal was meant to be used -- to pace yourself on extended steady state intervals.

Assuming you've done the 30 min time trial, it means you've found a location where you can ride 30 minutes at full gas relatively uninterrupted. This is good. Typically loops around a local park works best. Now you want to do repeated laps on the same terrain at varying intensity levels (use a combination of HR & RPE is gauge your intensity). My local park loop is 3.33 miles long so I did 9 laps broken up into 3 lap segments -- Low, Moderate, High. Roughly corresponds to Zone 1-2, 3-4, 4+. Doing it in this order is important due to the "drifting effect". During extended periods of exercise your heart raise will steadily rise even if your power output is constant (aka drifting -- the fitter you are the less pronounced this effect will be). PowerCal does a very good job of decoupling this drift effect since its calculates power based on HR variability (essentially the rate of change in HR -- if you've done calculus this makes total sense) and not raw HR. Its not perfect but good enough for its intended use. Also, make sure you use the lap feature on your head unit so that when you upload to strava you'll get power averages for each lap. Finally, avoid stimulants when you're doing this test. Stimulants don't mess with PowerCal too much over the course of a longer ride, but since you're doing averages of short laps the spike in power will skew the calculations.

Now for the post ride analysis. The average power (+/- 20%) for your low intensity rides because your power zone 1, aka active recovery. The next cutoff is your moderate intensity average power. Think of this as your all day cruising zone. The next cutoff is your "FTP" from the 30 minute TT. This is your tempo zone, and pretty much your sweet spot. Finally the last cutoff should be your average from your high intensity laps. Think of this as your full gas zone; you probably won't be able to hold it for more than a couple of minutes. These zone are baselines and the cutoffs aren't rigid so feel free to fine tune them as you ride and learn more about your body's physiological response to exercise. Also, as your fitness increases you'll need to redo the tests. But as I said earlier, PowerCal fails when you have a steadily rising core temp -- it interprets a gradual increase in HR as you doing more work but really its just you needing to ditch the arm warmers and full finger gloves. Its been especially problematic for me lately due to the varying temperatures throughout my ride and my laziness to add/remove layers when appropriate. Great tool once you work out the quirks.

I'm in no way qualified to give exercise advice. Just a geek who likes stats, politics and gadgets.
Nice process! Jives with my Powercal experience and usage, but takes the setup several steps further. Cycleops also has a calibration procedure, as you probably know, put which involves using a power meter to do an effort step-test, I think it was 8min segments at increasing effort, and an ANT+ USB dongle to connect and reprogram that data into Powercal via their PowerAgent software.

Anyway, it looks like you've developed a good system, so kudos!
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Old 04-23-15, 06:37 PM
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Originally Posted by Eyedrop
How likely is it that the used powertap will need a torque tube? Judging by the pictures and braking surface, it dosent look very used. Should I just pull the trigger guys?
I bought 2 used wired Powertaps. No problems after a couple of years.
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Old 04-23-15, 06:39 PM
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Originally Posted by Eyedrop
I installed a tubular tire on my zipp 400 last night (without gluing) and it was just as easy, if not easier than a clincher. Ive got a set of continental sprinter tubular tires ready and have 2 used cheapo spares coming from a friend. Only problem I see is having to spend more money on repairing flats, and I'll have to pump them up more often. I've been lucky with the lack of flats throught my cycling days and I'm praying it's gonna stay that way.
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Old 04-23-15, 07:43 PM
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Originally Posted by chaadster
Nice process! Jives with my Powercal experience and usage, but takes the setup several steps further. Cycleops also has a calibration procedure, as you probably know, put which involves using a power meter to do an effort step-test, I think it was 8min segments at increasing effort, and an ANT+ USB dongle to connect and reprogram that data into Powercal via their PowerAgent software.

Anyway, it looks like you've developed a good system, so kudos!
Thanks! I started out using the standard Allen/Coggan power zones but that clearly was never going to work due to the fact that those zones rely on instantaneous feedback from the drive train -- ergo the need for alternate zones.

I'm not familiar with that calibration method but according to powertap calibration isn't very useful.

Last edited by yankeefan; 04-23-15 at 07:51 PM.
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Old 04-23-15, 07:55 PM
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After looking at the review of the joule, I think I might just go with an LYC for cost and reliability. Is the USB cradle required to download your data? Or can you just use a standard usb cable?
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Old 04-23-15, 08:45 PM
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Originally Posted by hubcyclist
since folks are talking power here, I don't know if anyone has seen or tried this app called poweredge, which uses weather data and gps to calculate power. I've only used it a couple of times as a novelty item (I don't have a phone mount and it doesn't work with the rflkt, so i can only review after the fact). Last week, I went out for a long ride which I'd categorize as tempo given the amount of effort I was putting in. The app said I had an avg power of 240 and NP of 274 on a 49 mile ride (I'm not sure what my FTP is, an educated guess is 280). I may be borrowing a powertap this weekend and I may put this app to the test, along with my FTP. I've seen zero real reviews on it, which says a lot, because if it was really spot on I think people would be raving about it.
Average power is basically worthless as a training tool. The only reason to use a power meter over a HRM is that you want real-time power data. Basically the purpose of a power meter is to tell you that you're doing 300W vs 280W. Its especially useful for short intervals since heart-rate lags.

Since the app can't measure your actual wind speed (at least iBikePower has that), it stands zero chance of being accurate. Have you seen the Strava calorie estimates? They frequently miss by a factor of 2.
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Old 04-23-15, 09:32 PM
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Originally Posted by Eyedrop
After looking at the review of the joule, I think I might just go with an LYC for cost and reliability. Is the USB cradle required to download your data? Or can you just use a standard usb cable?
You need the cradle.
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Old 04-24-15, 05:19 AM
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Originally Posted by yankeefan
Thanks! I started out using the standard Allen/Coggan power zones but that clearly was never going to work due to the fact that those zones rely on instantaneous feedback from the drive train -- ergo the need for alternate zones.

I'm not familiar with that calibration method but according to powertap calibration isn't very useful.
I think I read about the calibration procedure in a DCRainmaker Powercal review, where he also wrote about Cycleops view of calibration, and my understanding was that they don't reccommend it only because they were not able to see a statistical rise in accuracy across a wide group of users, though for some it may be useful. I think they also figured that anyone with a power meter to do the test wouldn't be likely have a Powercal. My situation, though, was while I train on a Cycleops PT300 Pro bike at a studio, setting up to do the test and getting the data was inconvenient, and my wired Powertap on my bike didn't have the ANT+ transmission to get the data to the computer! Oi. I now have a wireless Powertap wheel for my bike, and sure enough, the Powercal has been left in the closet.
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Old 04-24-15, 07:03 AM
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I've ordered a new LYC and cradle. Everything should be here by May 1st. What's the best mounting method of the LYC to tri bars? Will I have to buy a special mount?
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Old 04-24-15, 07:13 AM
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Originally Posted by Eyedrop
I've ordered a new LYC and cradle. Everything should be here by May 1st. What's the best mounting method of the LYC to tri bars? Will I have to buy a special mount?
I've never seen a tribar mount for Cervo; may have to stem mount, or get one of those "bar extenders" that give extra mounting space (perpendicular to the centerline of the bike).
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