iBike vs. Power tap
#51
Senior Member
Thread Starter
Join Date: Feb 2015
Location: Prescott, AZ
Posts: 125
Bikes: 1999 Trek 2000T 47cm, 2017 Ribble R872 Ultegra Di2 47cm, 2010 Trek Top Fuel 9.8 15.5in
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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.
#52
Thread Killer
Join Date: Aug 2008
Location: Ann Arbor, MI
Posts: 12,431
Bikes: 15 Kinesis Racelight 4S, 76 Motebecane Gran Jubilée, 17 Dedacciai Gladiatore2, 12 Breezer Venturi, 09 Dahon Mariner, 12 Mercier Nano, 95 DeKerf Team SL, 19 Tern Rally, 21 Breezer Doppler Cafe+, 19 T-Lab X3, 91 Serotta CII, 23 3T Strada
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 3132 Post(s)
Liked 1,700 Times
in
1,027 Posts
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.
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.
Anyway, it looks like you've developed a good system, so kudos!
#53
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,843
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 927 Times
in
612 Posts
I bought 2 used wired Powertaps. No problems after a couple of years.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
#54
Super Moderator
Join Date: Jul 2004
Location: Ffld Cnty Connecticut
Posts: 21,843
Bikes: Old Steelies I made, Old Cannondales
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 1173 Post(s)
Liked 927 Times
in
612 Posts
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.
__________________
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
Bikes: Old steel race bikes, old Cannondale race bikes, less old Cannondale race bike, crappy old mtn bike.
FYI: https://www.bikeforums.net/forum-sugg...ad-please.html
#55
Senior Member
Join Date: Oct 2014
Location: NYC
Posts: 526
Bikes: Too many to list
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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!
Anyway, it looks like you've developed a good system, so kudos!
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.
#56
Senior Member
Thread Starter
Join Date: Feb 2015
Location: Prescott, AZ
Posts: 125
Bikes: 1999 Trek 2000T 47cm, 2017 Ribble R872 Ultegra Di2 47cm, 2010 Trek Top Fuel 9.8 15.5in
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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?
#57
Senior Member
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.
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.
#58
Senior Member
Join Date: Apr 2010
Location: Mountain View, CA USA and Golden, CO USA
Posts: 6,341
Bikes: 97 Litespeed, 50-39-30x13-26 10 cogs, Campagnolo Ultrashift, retroreflective rims on SON28/PowerTap hubs
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 550 Post(s)
Liked 325 Times
in
226 Posts
#59
Thread Killer
Join Date: Aug 2008
Location: Ann Arbor, MI
Posts: 12,431
Bikes: 15 Kinesis Racelight 4S, 76 Motebecane Gran Jubilée, 17 Dedacciai Gladiatore2, 12 Breezer Venturi, 09 Dahon Mariner, 12 Mercier Nano, 95 DeKerf Team SL, 19 Tern Rally, 21 Breezer Doppler Cafe+, 19 T-Lab X3, 91 Serotta CII, 23 3T Strada
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 3132 Post(s)
Liked 1,700 Times
in
1,027 Posts
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'm not familiar with that calibration method but according to powertap calibration isn't very useful.
#60
Senior Member
Thread Starter
Join Date: Feb 2015
Location: Prescott, AZ
Posts: 125
Bikes: 1999 Trek 2000T 47cm, 2017 Ribble R872 Ultegra Di2 47cm, 2010 Trek Top Fuel 9.8 15.5in
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 97 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
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?
#61
Thread Killer
Join Date: Aug 2008
Location: Ann Arbor, MI
Posts: 12,431
Bikes: 15 Kinesis Racelight 4S, 76 Motebecane Gran Jubilée, 17 Dedacciai Gladiatore2, 12 Breezer Venturi, 09 Dahon Mariner, 12 Mercier Nano, 95 DeKerf Team SL, 19 Tern Rally, 21 Breezer Doppler Cafe+, 19 T-Lab X3, 91 Serotta CII, 23 3T Strada
Mentioned: 30 Post(s)
Tagged: 0 Thread(s)
Quoted: 3132 Post(s)
Liked 1,700 Times
in
1,027 Posts
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).