Archive for February 10, 2012
Happy days are here again as I have remounted my iBike Dash with Power. Props to the good folks at iBike who repaired a broken enclosure bracket on my iBike Dash device and a broken LCD screen on my iBike Gen III device – for free, even though my Gen III was out of warranty. Those of you who know me well (or even partially well), know that I’m pretty much obsessed with topographical maps, bike riding, and analyzing bike ride data — especially climbing related data. The screenshot above is from my commute home from work.
The iBike Dash clearly has the best in-ride graphical user interface of all bike computers/GPS devices — making full use of the color iPhone touch screen (see this post for screenshots – http://toonecycling.wordpress.com/2011/04/21/equipment-update-ibike-dash-power-meter-wheels-and-tires-galore/). But the best two features of the iBike for me are the internal gyrometer for measuring slope and the iBike ride analysis software, which in my opinion, is the best graphing software for displaying power, cadence, elevation, heartrate, and slope all on one screen. The slope is obtained using an internal gyrometer, which is much more accurate than a barometric obtained gradient as the barometer can never catch up with the slope changes in a severely rolling area (such as where I live).
iBike slope graph for a particularly insane section of rollers
On my way into work today, I figured out a topic for my next journal article — developing an algorithm for analyzing ride data from any device, combined with data reported from other devices for the same segments, combined with survey-based and/or radar acquired elevation data to come up with a “best fit” elevation profile. On my way home from work, I was inspired to do a climbing route with some of the steeper climbs on Shades Mountain and Little Valley Mountain including a nearly 30% driveway off of Altaloma. Here is the topocreator map:
About the journal article I am going to write, look at the complete iBike stats below, particularly note the “Climbing” amount. The iBike only registers 4000′ of climbing, whereas the Garmin registered nearly 5700′. The zoomed in iBike graph below the stats shows why. Even with a 29% gradient climbing at least 30 feet, the barometric sensor only registered a 2 foot climb for the entire driveway since I turned around and immediately skidded my way back down the driveway across the road and into the grass on the other side (I can’t imagine the wear and tear on the brakes of whoever lives in that house). Even the iBike gyrometer couldn’t turn around fast enough from the extreme climb to the extreme descent with it only registering a 2 or 3% descent even though it should have been -29%. Interestingly, the Garmin registered 30 feet of climbing for the driveway and 25 feet of descending even though I noticed that the % gradient was pegged at +17% the whole way down the driveway. I guess the % display only updates itself at a slower rate than the internal elevation recording.
Dist: 34.55 mi (2:27:57) Energy: 1631.9 kJ Cals Burn: 1560.1 kcal Climbing: 3997 ft Braking: -270.5 kJ (-16.6%) Min Avg Max Power 0 183.8 717 W Aero 0 102.7 2471 W Rolling 0 25.6 101 W Gravity -3620 -11.0 548 W Speed 0.0 14.0 56.3 mi/h Wind 0.0 15.3 49.0 mi/h Elev 188 477 851 ft Slope -20.2 -0.24 29.2 % Caden 0 73.9 118 rpm HR 66 123.1 164 bpm NP:216W IF:0.72 TSS:128 VI:1.18 CdA: 0.342 m^2; Crr: 0.0055 168 lbs; 2/10/2012 11:28 AM 56 degF; 1013 mbar
Zoomed in S Cove Dr descent (56mph) plus Altaloma driveway climb (29%) – click to enlarge. Demonstrates fundamental problem with barometric pressure sensors for altitude measurements in constantly changing terrain.
Altaloma driveway climb
Altaloma driveway climb
Renfroe climb – S Cove descent – Altaloma driveway climb (click to enlarge)