Well first of all an ibike update. Battery is still good at 280V, and I finally filled the data log memory. It takes about 2 weeks of 1-1.5 hour rides. Still works fine, although I suspect that it is adjusting the altitude that I set it at as the barometer rises... that's not a huge error. I should be starting my rides at about 60m above sea level but today my local hill had grown to 175m. Hmmm. I'm getting used to riding for power measurement and remembering to minimise my coasting. I find myself sprinting downhill just to lift my average... with has crept from about 160 up to just under 190W, but if you play with your data (it's a CSV file that you can dump into a spreadsheet program like Excel or OpenOffice) and remove the zeros the average is more like 220W now, up from just under 200. That makes sense as you are really interested in what power you can develop, not how much freewheeling and downhills you can conjure up on a ride...
On other matters, like Basso's suspension and Landis's ongoing laboratory problems, there's a nice summation of where we are at here at Bicycling mag. Cofidis pro Bradley Wiggins reckons it's good for cycling to have Basso suspended (BBC report here). Meanwhile CyclingPost tells us Cunego has won Trentino again. And PEZ on how to ride a Gran Fondo is a good fun read. And lastly don't miss the fun at the Rundfahrt... Graeme Brown is in 3rd overall and has got a 2nd and a 3rd so far. CyclingNews report here.
Saturday, April 28, 2007
Tuesday, April 24, 2007
1989 World Cycling Championships Finish
What a race.. Fignon, Konyshev, Kelly... Kelly pulls his foot in the sprint! Oh for a clipless pedal, Sean!
Landis: more intrigue
We can't we just do it right? Why does every move that could 'prove' Landis innocent - or guilty - have to be tarnished with suspicion, doubt and intrigue? Today we seemingly have L'Equipe reporting on the unreleased results of the USADA's test of the previously untested TdeF B-samples. (The respective A-samples were negative, only stage 17 came out with an inappropriate epitestosterone ratio.) Whilst we are fascinated to learn that some of these show synthetic testosterone, it's disappointing that we are yet again reading a leak. Why can't we see results released in a proper, controlled way? It gets worse. The Landis legal team has claimed that their UCLA independent witness was denied access during at least some of the tests. If true, why allow access sometimes and not at other times? Why immediately throw the tests into doubt by excluding an independent observer? Why would you do that?
You could blame L'Equip. They could indeed show more restraint. But we don't shoot the messenger, do we? You could blame the leaker - he or she could also just act appropriately and resolve the matter. But they are only human. You could blame me - and yourselves - too, for wanting to know so badly that we have created the very demand that makes leaking worthwhile. But (if true) how do you explain the subterfuge involved in excluding the observer? Why does it have to be this hard?
Cyclingnews reports here and the Sydney Morning Herald has more.
You could blame L'Equip. They could indeed show more restraint. But we don't shoot the messenger, do we? You could blame the leaker - he or she could also just act appropriately and resolve the matter. But they are only human. You could blame me - and yourselves - too, for wanting to know so badly that we have created the very demand that makes leaking worthwhile. But (if true) how do you explain the subterfuge involved in excluding the observer? Why does it have to be this hard?
Cyclingnews reports here and the Sydney Morning Herald has more.
Saturday, April 21, 2007
Follow the Tour de Georgia by GPS and satellite
Interesting take on the Tour de Georgia... from above, from the ground, by GPS, by Flickr... you name it. It's awesome, really. A great concept, mashing together a GPS-tracker with video and still picture feeds and a chatroom. Shame about the lame US comedy commentating team...
The screenshot gives you an idea.
Friday, April 20, 2007
Browse these cycling and power links
- A great place to start... Machinehead Software. Power calculator is here but there's lots of great stuff
- This looks interesting... a running-based anaerobic sprint test... not exactly cycling but interesting, and a useful way to calculate power over a 35m run... annoying yellow advert takes the eye, too. Uuuugh. Aaahh but it links to this Wingate test... all is not lost. Not a bad site, actually, full of info. Like this chart on "Percentile norms for Relative Peak Power for active young adults" - especially interesting, if you happen to have a power meter handy! An average sort of club racer, IMHO, would fall into the 90th percentile, surely? Having said that I'm neither young nor average (who is?) and I go right off the scale... remembering this is PEAK power, not sustained... and I'm not particularly overweight (nor skinny).
Male | Female | |
%Rank | Watts.Kg | Watts.Kg |
90 | 10.89 | 9.02 |
80 | 10.39 | 8.83 |
70 | 10.20 | 8.53 |
60 | 9.80 | 8.14 |
50 | 9.22 | 7.65 |
40 | 8.92 | 6.96 |
30 | 8.53 | 6.86 |
20 | 8.24 | 6.57 |
10 | 7.06 | 5.98 |
Maud, P.J., and Schultz B.B: 1989
- And this...from the same link: "Percentile norms for Peak Power for active young adults":
Male | Female | |
%Rank | Watts | Watts |
90 | 822 | 560 |
80 | 777 | 527 |
70 | 757 | 505 |
60 | 721 | 480 |
50 | 689 | 449 |
40 | 671 | 432 |
30 | 656 | 399 |
20 | 618 | 376 |
10 | 570 | 353 |
Maud, P.J., and Schultz B.B: 1989
Looks like they surveyed some pretty average active people... perhaps non cyclists?- How about the Human Powered Vehicle association?
- Or look at this technical exercise in analysing the forces at work on a bike.
- Or this interesting exercise by FLAcyclist in comparing the power required to overcome a hilly bike course vs a less hilly but longer one...
- And Analytic Cycling is a treasure trove that will have you staring at the computer for hours... STOP IT! Go outside and ride!
- Still here? Ok, how about Aerodynamics for cycling?
- If you are getting into the maths, try this Human Power eJournal for size.
- And last but not least the informative guys at CyclingPeaks software discuss reading and comparing power outputs at different durations.
Thursday, April 19, 2007
a quick browse around the web
Just did a quick browse around the web... you may enjoy it, don't know...
- Started with Wikipedia - cycling
- Osteoporosis and master's cyclists (that's me): "Weight-bearing exercise performed during teen and young adult years did not appear to influence BMD, as there were no differences at any site between those within the upper and lower 50th percentiles for weight-bearing exercise during the 12-18, 19-34, or 35-49 year time periods. These data indicate that master cyclists with a long history of training exclusively in cycling have low BMD compared to their age-matched peers. Although highly trained and physically fit, these athletes may be at high risk for developing osteoporosis with advancing age."
- Back to Wiki - Bicycle
- Dartmouth's cyclewiki
- Would you believe it - the UCI's official ProTour mediaWiki
- Not sure about this one - worldnakedbikeride Wiki
- Back to Wikipedia - Aussie cyclists
- Cyclepedia.org
- Interesting Aussie site, Spinopsys
- Biocrawler... on McEwen
Monday, April 16, 2007
O'Grady now leads the ProTour!
From TuttobiciWeb comes the news... O'Grady has stepped up a gear to lead Freire overall!
"15/04/2007 Stuart O'GRady è leader del Pro Tour
Grazie all'odierna vittoria nella Parigi-Roubaix l'australiano Stuart O'Grady passa al comando della classifica del Pro Tour. Il portacolori della Csc ha 79 punti contro i 77 dello spagnolo Oscar Freire e i 62 di Davide Rebellin. Ottavo con 50 punti Alessandro Ballan, vincitore domenica scorsa del Giro delle Fiandre. Prossima gara del Pro Tour l'Amstel Gold Race, in programma domenica prossima.
CLASSIFICA DI PRO TOUR
1 Stuart O'Grady (Aus) Team CSC 79 pts
2 Oscar Freire Gomez (Spa) Rabobank 77
3 Davide Rebellin (Ita) Gerolsteiner 62
4 Alberto Contador Velasco (Spa) Discovery Channel Pro Cycling Team 58
5 Juan Jose Cobo Acebo (Spa) Saunier Duval-Prodir 57
6 Tom Boonen (Bel) Quickstep-Innergetic 57
7 Andreas Klöden (Ger) Astana 53
8 Alessandro Ballan (Ita) Lampre-Fondital 50
9 Roger Hammond (GBr) T-Mobile Team 45
10 Samuel Sanchez Gonzalez (Spa) Euskaltel-Euskadi 45
11 Tadej Valjavec (Slo) Lampre-Fondital 45
12 Robbie McEwen (Aus) Predictor-Lotto 44
13 Kim Kirchen (Lux) T-Mobile Team 41
14 Marcus Burghardt (Ger) T-Mobile Team 40
15 Juan Antonio Flecha Giannoni (Spa) Rabobank 40
16 Leif Hoste (Bel) Predictor-Lotto 40
17 Allan Davis (Aus) Discovery Channel Pro Cycling Team 40
18 Alexandre Vinokourov (Kaz) Astana 38
19 Luis Leon Sanchez Gil (Spa) Caisse d'Epargne 38
20 Luca Paolini (Ita) Liquigas 36"
"15/04/2007 Stuart O'GRady è leader del Pro Tour
Grazie all'odierna vittoria nella Parigi-Roubaix l'australiano Stuart O'Grady passa al comando della classifica del Pro Tour. Il portacolori della Csc ha 79 punti contro i 77 dello spagnolo Oscar Freire e i 62 di Davide Rebellin. Ottavo con 50 punti Alessandro Ballan, vincitore domenica scorsa del Giro delle Fiandre. Prossima gara del Pro Tour l'Amstel Gold Race, in programma domenica prossima.
CLASSIFICA DI PRO TOUR
1 Stuart O'Grady (Aus) Team CSC 79 pts
2 Oscar Freire Gomez (Spa) Rabobank 77
3 Davide Rebellin (Ita) Gerolsteiner 62
4 Alberto Contador Velasco (Spa) Discovery Channel Pro Cycling Team 58
5 Juan Jose Cobo Acebo (Spa) Saunier Duval-Prodir 57
6 Tom Boonen (Bel) Quickstep-Innergetic 57
7 Andreas Klöden (Ger) Astana 53
8 Alessandro Ballan (Ita) Lampre-Fondital 50
9 Roger Hammond (GBr) T-Mobile Team 45
10 Samuel Sanchez Gonzalez (Spa) Euskaltel-Euskadi 45
11 Tadej Valjavec (Slo) Lampre-Fondital 45
12 Robbie McEwen (Aus) Predictor-Lotto 44
13 Kim Kirchen (Lux) T-Mobile Team 41
14 Marcus Burghardt (Ger) T-Mobile Team 40
15 Juan Antonio Flecha Giannoni (Spa) Rabobank 40
16 Leif Hoste (Bel) Predictor-Lotto 40
17 Allan Davis (Aus) Discovery Channel Pro Cycling Team 40
18 Alexandre Vinokourov (Kaz) Astana 38
19 Luis Leon Sanchez Gil (Spa) Caisse d'Epargne 38
20 Luca Paolini (Ita) Liquigas 36"
Kelly, O'Grady, Paris-Roubaix and Le Tour
OK, it's stunning. Stuart O'Grady has won Paris-Roubaix. It's (sadly) not big news here in Australia, at least we haven't heard a lot about it yet - but it should be HUGE. Hopefully as the news filters through it will get some more attention.
As Cyclingnews points out today, "In addition to first being the race's first Australian victor, O'Grady became the first English-speaking rider since the great Sean Kelly to win Paris-Roubaix, and not only the first Australian, but indeed the first cyclist from any Commonwealth country to win this race (Kelly is from Eire, which is not part of the Commonwealth). And the last time O'Grady won a race on a velodrome, it was nothing less than a Gold medal in the Madison at the Athens 2004 Olympics (with Graeme Brown)."
Before Stuey won I was going to note (as Irish hard-man and road sprinter Sean Kelly does here in Cyclingnews) that the way pro riders target their season has changed over the last 20-30 years. CN also recently reported that "the last time a rider did the Paris-Roubaix-Tour de France double was Bernard Hinault in 1981. Before that, Eddy Merckx took both races in 1971. Merckx was the last rider to win the Tour and triumph in Flanders in the same year, way back in 1969." Stuey won't win Le Tour but he has worn the Maillot jaune.
It's interesting that Stuey is a little in Kelly's mould. A hard man, known for his sprinting as well as his versatility. Kelly was arguably a better sprinter but the way he toughed it out in the mountains was a rare treat. Stuey too has been known to have a dig in the high stuff, if there was a sniff of some time to be gained on GC. But Roubaix is dead flat and cobbled, so this win is a monument to O'Grady's versatility.
Thinking along these lines, these days we don't expect to see a sprinter like Boonen contest the GC at Le Tour, as we didn't expect to see Armstrong do Paris-Roubaix; whereas Merckx and Hinault contested the classics, the GC, the mountains... even the sprints. We can expect nothing less than increasing specialisation over time if the individual targets are worth it - and that's exactly what has happened. Le Tour is so big that it alone justifies a rider's salary. Whilst we have always had some specialists - it's a physiological thing after all - it wasn't possible for a pro to to make enough money (or even to retain their place in a team) without riding lots of races over the course of a year and being good at more than type of race. Which is why we'll 'never' see another Merckx, if things stay as they are but will 'probably' see more Armstrongs, Boonens and - I hope - more O'Gradys.
As Cyclingnews points out today, "In addition to first being the race's first Australian victor, O'Grady became the first English-speaking rider since the great Sean Kelly to win Paris-Roubaix, and not only the first Australian, but indeed the first cyclist from any Commonwealth country to win this race (Kelly is from Eire, which is not part of the Commonwealth). And the last time O'Grady won a race on a velodrome, it was nothing less than a Gold medal in the Madison at the Athens 2004 Olympics (with Graeme Brown)."
Before Stuey won I was going to note (as Irish hard-man and road sprinter Sean Kelly does here in Cyclingnews) that the way pro riders target their season has changed over the last 20-30 years. CN also recently reported that "the last time a rider did the Paris-Roubaix-Tour de France double was Bernard Hinault in 1981. Before that, Eddy Merckx took both races in 1971. Merckx was the last rider to win the Tour and triumph in Flanders in the same year, way back in 1969." Stuey won't win Le Tour but he has worn the Maillot jaune.
It's interesting that Stuey is a little in Kelly's mould. A hard man, known for his sprinting as well as his versatility. Kelly was arguably a better sprinter but the way he toughed it out in the mountains was a rare treat. Stuey too has been known to have a dig in the high stuff, if there was a sniff of some time to be gained on GC. But Roubaix is dead flat and cobbled, so this win is a monument to O'Grady's versatility.
Thinking along these lines, these days we don't expect to see a sprinter like Boonen contest the GC at Le Tour, as we didn't expect to see Armstrong do Paris-Roubaix; whereas Merckx and Hinault contested the classics, the GC, the mountains... even the sprints. We can expect nothing less than increasing specialisation over time if the individual targets are worth it - and that's exactly what has happened. Le Tour is so big that it alone justifies a rider's salary. Whilst we have always had some specialists - it's a physiological thing after all - it wasn't possible for a pro to to make enough money (or even to retain their place in a team) without riding lots of races over the course of a year and being good at more than type of race. Which is why we'll 'never' see another Merckx, if things stay as they are but will 'probably' see more Armstrongs, Boonens and - I hope - more O'Gradys.
Friday, April 13, 2007
ibike - part 5 - the fun begins
OK, so now I'm getting into it. It's addictive. I'm a data junkie and it's making me get out on the bike and ride, just to see what it looks like when I sprint, chase a car or climb a hill. Then I want to compare sprints, compare hills... goddamn it, I wish I had one 20 years ago! (But they didn't exist at this price, of course.)
That's the good side of the ibike - real data that makes sense. You've got to set it up right and do the coast-down test properly, as per spec, and make sure the battery is delivering the goods. But once done it's great. Of course today I punctured and swapped front wheels, but because it's just a magnetic pickup there was no sweat. I could even swap bikes as I've got a spare mount and pickup already on bike number 2. So I think ibike is still looking like a pretty good thing.
Bad news? It goes a bit screwy if you watch the Wattage display too much (it seems to jump around constantly, especially on the flat, only settling down when efforts are made, in a sprint or in a climb) - but when you download to the PC the odd figures seem to have disappeared and clarity returns. And the peak figures on the LCD don't always match the data logged. The battery seems to play a part in this, as does road surface - bumps and corners definitely throw it off.
So on to the fun.. the screenshot on the left shows power in blue and bike speed in green. You can see steady state on the left, then I accelerate to catch a slow-moving Toyota 'Landbruiser' that pulled out in front of me. You see both power and speed rise as I chase, peaking at around 865W and 45kmh or so; then as I get into the draft speed stays up (for a while, I didn't stay on as there's a nasty climb around the corner and I'm not that fit!) whilst power falls off sharply. The ibike seems to handle 'sucking wheels' pretty well. You can see that power falls away rapidly to zero until I hit the climb and have to get pedalling again. Speed falls away too and you can see me approach 300W on the lower part of the 10% climb (the bump on the right).
The next sreenshot shows a zoom-in on that power peak. You can see the effort to accelerate, the speed rising and then the power clearly falls off as I get into the draft, despite speed continuing to rise. In fact the car eventually accelerated, having suddenly realised that the rider they pulled out in front off at that T-junction was still there... and I let him go, as you see the speed dropping again. Wow.
Even better, the power breakdown (the colored box centre-screen) shows what was happening at the point where the cursor sits... all of that green in the pie chart is acceleration. The cursor itself is the black vertical line right on the power peak. So it all makes sense. When I move the cursor into the 'draft zone' the proportions all change... as you'd hope.
Bottom line? It works!
That's the good side of the ibike - real data that makes sense. You've got to set it up right and do the coast-down test properly, as per spec, and make sure the battery is delivering the goods. But once done it's great. Of course today I punctured and swapped front wheels, but because it's just a magnetic pickup there was no sweat. I could even swap bikes as I've got a spare mount and pickup already on bike number 2. So I think ibike is still looking like a pretty good thing.
Bad news? It goes a bit screwy if you watch the Wattage display too much (it seems to jump around constantly, especially on the flat, only settling down when efforts are made, in a sprint or in a climb) - but when you download to the PC the odd figures seem to have disappeared and clarity returns. And the peak figures on the LCD don't always match the data logged. The battery seems to play a part in this, as does road surface - bumps and corners definitely throw it off.
So on to the fun.. the screenshot on the left shows power in blue and bike speed in green. You can see steady state on the left, then I accelerate to catch a slow-moving Toyota 'Landbruiser' that pulled out in front of me. You see both power and speed rise as I chase, peaking at around 865W and 45kmh or so; then as I get into the draft speed stays up (for a while, I didn't stay on as there's a nasty climb around the corner and I'm not that fit!) whilst power falls off sharply. The ibike seems to handle 'sucking wheels' pretty well. You can see that power falls away rapidly to zero until I hit the climb and have to get pedalling again. Speed falls away too and you can see me approach 300W on the lower part of the 10% climb (the bump on the right).
The next sreenshot shows a zoom-in on that power peak. You can see the effort to accelerate, the speed rising and then the power clearly falls off as I get into the draft, despite speed continuing to rise. In fact the car eventually accelerated, having suddenly realised that the rider they pulled out in front off at that T-junction was still there... and I let him go, as you see the speed dropping again. Wow.
Even better, the power breakdown (the colored box centre-screen) shows what was happening at the point where the cursor sits... all of that green in the pie chart is acceleration. The cursor itself is the black vertical line right on the power peak. So it all makes sense. When I move the cursor into the 'draft zone' the proportions all change... as you'd hope.
Bottom line? It works!
ibike - part 4 - the software install
Well the software looked good enough sitting on the CD-ROM, and it seemed to install on my PC OK - and I followed the instructions - but it failed to find the USB driver first up. I followed the instructions again, went through the whole install and once again it failed to find the driver. So I went manual in control panel and found the driver had indeed installed correctly on my hard drive, it's just that the "automatic, preferred" search doesn't look there... of course. Wonder if this happens to everyone? Anyway, it really does extract and copy it to your ibike program folder, so a bit of searching will find it. It's just a manual approach is needed when 'auto' fails. Once loaded it all worked.
The software is simple. Connect, download all or some files... ooops, it crashed. And the ibike itself froze. OK, this has only happened once, but again I followed instructions, restarted the software and took the battery out of the ibike. I popped the battery back in and it fired up again and has worked flawlessly since. In fact it works better now than before. The battery started life reading 2.80V and fell to 2.70V during the 2nd ride, before recovering to 2.78V. However after refitting (and perhaps putting the cover back on a bit tighter?) it reads 2.82V pre-ride and hasn't fallen below 2.77V. The instructions say to get a new battery if it falls below 2.75V before a ride. Perhaps my first-day glitches were battery related?
Anyway, back to the software. It's good enough. It loads up the whole ride as a .CSV file and you can 'play' with power, wind speed, elevation, slope and bike speed for starters. You basically can graph it as you like it, including looking at neat breakdowns of acceleration, hill and friction readings at any point in the ride. And you can probably read and modify it in any spreadsheet, too, given that it's saved as a .CSV (but I haven't tried - yet). It's simple, but does the job for a data junkie like me. It's strange though that the ibike itself displays slightly different maximum values than that logged in the data file. That aside, overall it's what I expected.
The software is simple. Connect, download all or some files... ooops, it crashed. And the ibike itself froze. OK, this has only happened once, but again I followed instructions, restarted the software and took the battery out of the ibike. I popped the battery back in and it fired up again and has worked flawlessly since. In fact it works better now than before. The battery started life reading 2.80V and fell to 2.70V during the 2nd ride, before recovering to 2.78V. However after refitting (and perhaps putting the cover back on a bit tighter?) it reads 2.82V pre-ride and hasn't fallen below 2.77V. The instructions say to get a new battery if it falls below 2.75V before a ride. Perhaps my first-day glitches were battery related?
Anyway, back to the software. It's good enough. It loads up the whole ride as a .CSV file and you can 'play' with power, wind speed, elevation, slope and bike speed for starters. You basically can graph it as you like it, including looking at neat breakdowns of acceleration, hill and friction readings at any point in the ride. And you can probably read and modify it in any spreadsheet, too, given that it's saved as a .CSV (but I haven't tried - yet). It's simple, but does the job for a data junkie like me. It's strange though that the ibike itself displays slightly different maximum values than that logged in the data file. That aside, overall it's what I expected.
Thursday, April 12, 2007
ibike - part 3 - the 'coast' setup
Right, so it's mounted and ready to go. We have total weight, it's leveled (so it can tell if it's climbing or descending) and it seems to be sensing wind speed OK. Now we need to calculate the aerodynamic drag and the friction between road and tyre. Now we can estimate this pretty well, but the "coast" test will actually time your deceleration run - ie measure the drag induced by you and your bike on the road. So out we went, ibike and I, on our Look KG76 for test number 1.
It's harder to find a flat, smooth quarter-mile of road than you'd think. Slightly uphill is good, downhill is bad, bad, bad as it distorts the results. So naturally I chose a road that looked flat-to-uphill but actually wasn't, so I got some fantastic results. Fantastic as in no way could it be real.
Look at this: 1459W, man! Beat that!
Oh well, back to the "coast" test. In fact I kept finding roads with dips, declines, potholes, corners and really smooth fast bits. Which raised a question or 2 in my mind. Like how accurate is it when road conditions vary? And how is it calculating wind speed, let alone direction? I guess it's a straight subtraction of total airflow "in" minus forward velocity, and angle isn't relevant, but the final figures look odd... anyway, wind aside, if I calibrate on a smooth fast road presumably I'll get errors unless I only ride on that exact same smooth fast road... so are the errors small enough that it won't matter? Or when I get to new territory should I re-calibrate?
So I chose to retest a few times (OK, about 5 times) and compare. Firstly the ibike captured the whole thing, despite my many, many retests - which is good - and secondly I never again got the sort of fantastic result I got with the first coast test. Instead of 1459W I was now in the region of 600-1000W tops (I was getting tired, too, after countless sprints!!). So which 'coastdown' is correct? Hmmm.
Now if you look at the screenshot on the left (of the ibike software) you will see a few strange things. Firstly it shows maximum Watts on this same ride as 1495, yet the LCD display showed a maximum of 1459! Oddly similar but dyslexically different. On the right of the pic you will see the figures for a precise moment in my ride. Using those figures (28kmh wind speed, 8.9% slope etc) you could indeed calculate that a 72 kg rider at 47.5kmh on that slope is indeed putting out about 2100W, not the 'fantastic' figure of 1459/95. But to me, fallible old me, I could have sworn the road was (a) almost flat and (b) that there was little if any wind.
If you take me at my word, that it was a flat road with nil wind then Kreuzotter calculates it as 715W. I'm happy with that. So - assuming a multiply-by-2 glitch occurred - there's an error of more than a percent or 2, isn't there? Hence my scepticism and need to rerun this "coastdown" test until it checks out against 'expectations'. Or am I too harsh? Did the mostly flat road dip and climb suddenly for an instant, or did I pull up on the bars, lifting the front wheel a tad (I was sprinting, after all)... and maybe the wind suddenly gusted? No, I reckon it was a glitch.
So, I think I've got the "coast" test figured out and I'll keep it "as is" for now until I see questionable figures. Certainly my max power figures have come back to earth. Some doubt remains over what happens if you ride very different terrain, but it's easy enough to re-do the coast setup if on super-smooth or super-rough road. Perhaps do the coast test just before a race on a new circuit? Certainly do it if you swap bikes, but that's a test I'm going to do later, just to see what the diffence may be... I suspect it'll be neglible, though, unless my race wheels really are that much better!
It's harder to find a flat, smooth quarter-mile of road than you'd think. Slightly uphill is good, downhill is bad, bad, bad as it distorts the results. So naturally I chose a road that looked flat-to-uphill but actually wasn't, so I got some fantastic results. Fantastic as in no way could it be real.
Look at this: 1459W, man! Beat that!
Oh well, back to the "coast" test. In fact I kept finding roads with dips, declines, potholes, corners and really smooth fast bits. Which raised a question or 2 in my mind. Like how accurate is it when road conditions vary? And how is it calculating wind speed, let alone direction? I guess it's a straight subtraction of total airflow "in" minus forward velocity, and angle isn't relevant, but the final figures look odd... anyway, wind aside, if I calibrate on a smooth fast road presumably I'll get errors unless I only ride on that exact same smooth fast road... so are the errors small enough that it won't matter? Or when I get to new territory should I re-calibrate?
So I chose to retest a few times (OK, about 5 times) and compare. Firstly the ibike captured the whole thing, despite my many, many retests - which is good - and secondly I never again got the sort of fantastic result I got with the first coast test. Instead of 1459W I was now in the region of 600-1000W tops (I was getting tired, too, after countless sprints!!). So which 'coastdown' is correct? Hmmm.
Now if you look at the screenshot on the left (of the ibike software) you will see a few strange things. Firstly it shows maximum Watts on this same ride as 1495, yet the LCD display showed a maximum of 1459! Oddly similar but dyslexically different. On the right of the pic you will see the figures for a precise moment in my ride. Using those figures (28kmh wind speed, 8.9% slope etc) you could indeed calculate that a 72 kg rider at 47.5kmh on that slope is indeed putting out about 2100W, not the 'fantastic' figure of 1459/95. But to me, fallible old me, I could have sworn the road was (a) almost flat and (b) that there was little if any wind.
If you take me at my word, that it was a flat road with nil wind then Kreuzotter calculates it as 715W. I'm happy with that. So - assuming a multiply-by-2 glitch occurred - there's an error of more than a percent or 2, isn't there? Hence my scepticism and need to rerun this "coastdown" test until it checks out against 'expectations'. Or am I too harsh? Did the mostly flat road dip and climb suddenly for an instant, or did I pull up on the bars, lifting the front wheel a tad (I was sprinting, after all)... and maybe the wind suddenly gusted? No, I reckon it was a glitch.
So, I think I've got the "coast" test figured out and I'll keep it "as is" for now until I see questionable figures. Certainly my max power figures have come back to earth. Some doubt remains over what happens if you ride very different terrain, but it's easy enough to re-do the coast setup if on super-smooth or super-rough road. Perhaps do the coast test just before a race on a new circuit? Certainly do it if you swap bikes, but that's a test I'm going to do later, just to see what the diffence may be... I suspect it'll be neglible, though, unless my race wheels really are that much better!
ibike - part 2 - mounting it on the bike and setup
No real problems here. The ibike is just like many other bike computers and comes with a bayonet-style mount that sits on your handlebars. I chose the standard size but there is also the larger vesrion if needed. Follow the instructions though, as you need to keep the ibike absolutely 'rock-solid' on the bars. I tried using old tyre as padding at first, just to make removal easier, but settled on the double sided tape provided instead. It's easy to fit, just plan where the wire goes first. It has to get down to the forks, where the magnetic pickup gets strapped on. I kept my old speedo in place and mounted the new gear on the opposite side of the bars and forks.
Mounted it looks like this...
And the mounting itself looks like this....
All in all - dead easy. Lots of twist ties to play with but no harder than a regular 'wired' bike computer. The screws that affix the ibike mount to the bars are a bit fiddly, but it's easier on a stand, or turn the bike upside down.
Once connected I powered it up and went into setup mode. All the expected stuff: time, date, total bike and rider weight, plus the 'turn 180' exercise which levels the unit. Again, good clear instructions and I used them (for once in my life). I also zeroed out the wind (I was in a garage) and took a guess as to altitude (later riding down to sea level to make that accurate - hey I was only out by 10m!).
All up - simple and quick.
Mounted it looks like this...
And the mounting itself looks like this....
All in all - dead easy. Lots of twist ties to play with but no harder than a regular 'wired' bike computer. The screws that affix the ibike mount to the bars are a bit fiddly, but it's easier on a stand, or turn the bike upside down.
Once connected I powered it up and went into setup mode. All the expected stuff: time, date, total bike and rider weight, plus the 'turn 180' exercise which levels the unit. Again, good clear instructions and I used them (for once in my life). I also zeroed out the wind (I was in a garage) and took a guess as to altitude (later riding down to sea level to make that accurate - hey I was only out by 10m!).
All up - simple and quick.
ibike - part 1 - the purchase experience
OK, so I chose the ibike.
The first hassle was the ibike shop on the web. They revamped it a bit since but you can't login to the shop without first clicking on a product and pretending to buy it (then the 'log-in' option finally appears). And when you try to log-in the login ID box is unclickable without 14 'tabs' to get you there. I tried 3 different browsers and 2 PCs... they all had the same trouble. Not everytime, just 9 times out of 10. Anyway, the tab-tab-tab until you get to the correct input box works. (Must admit I just logged in fine, so who knows?)
Enough whinging. I bought it online and found that the 'tracking' option didn't work for International US Post. Not to worry, I guess. 10 working days later it turned up fine, but opened by Australian Quarantine Services. Must have looked suss with 'Velocomp' written on the box... hmmm. Go figure.
The box looks like this:
Which is fine, although for around $A600 it's a trifle underwhelming. Still, it's the technology we are buying, isn't it?
And opening it up we find the device itself, which is tiny and very light (which is good, right?):
It's showing average Watts here in this pic but it will also show maximum values.
And then I mounted it on the bike... well 2 bikes, actually. I had bought an extra mount, so I could swap from bike to bike with ease, something I saw as a killer feature of the ibike over almost all its competition.
More soon!
The first hassle was the ibike shop on the web. They revamped it a bit since but you can't login to the shop without first clicking on a product and pretending to buy it (then the 'log-in' option finally appears). And when you try to log-in the login ID box is unclickable without 14 'tabs' to get you there. I tried 3 different browsers and 2 PCs... they all had the same trouble. Not everytime, just 9 times out of 10. Anyway, the tab-tab-tab until you get to the correct input box works. (Must admit I just logged in fine, so who knows?)
Enough whinging. I bought it online and found that the 'tracking' option didn't work for International US Post. Not to worry, I guess. 10 working days later it turned up fine, but opened by Australian Quarantine Services. Must have looked suss with 'Velocomp' written on the box... hmmm. Go figure.
The box looks like this:
Which is fine, although for around $A600 it's a trifle underwhelming. Still, it's the technology we are buying, isn't it?
And opening it up we find the device itself, which is tiny and very light (which is good, right?):
It's showing average Watts here in this pic but it will also show maximum values.
And then I mounted it on the bike... well 2 bikes, actually. I had bought an extra mount, so I could swap from bike to bike with ease, something I saw as a killer feature of the ibike over almost all its competition.
More soon!
Power to the people - power meters for serious cycling
When I started this riding gig I was 16 and it was 1973. The bike was an Aussie-made Alcon, circa late 1930s and well looked after, if hand-painted. 28inch tyres, 40spoke wheels, diamond outrigger with sliding adjustment for handlebar reach and just 2 cogs on the back. On one side of the wheel was a freewheel and the other a fixie. Cool way to get started, eh? Even cooler was the mechanical odometer that clicked over incrementally with every turn of the front wheel. Ahhh, data! I started writing it down. Curiously it made me ride a bit more, just to get a scrap more data.
In the 1980s I found myself with electronic assistance in my data habit: a cycle 'computer', although all it really did was count wheel revs using a magnet and show elapsed time. It did allow me to see my current and average velocity, rather than doing the usual sums at home after the ride. And it was more accurate than some of the guesstimates I had to make. Now that sort of technology got a bit better over the last 25 years or so, but essentially remains as it was: a bunch of data based on wheel rotation over time, displayed on an LCD. (Although some of these new options are very sophisticated: check out BikeBrain for example)
Now this did make me ride for longer distances, and do more miles each week, as I could actually and accurately see when I had slacked off. And being data-obsessed I just wanted to push teh totals ever higher. Funnily enough I still had to chase down attacks, stick with the peleton over varying terrain and avoid being dropped, irrespective of what the displayed velocity was. But now I could also go 'ah, look at that average' after a hard crit.
The next leap forward in this history lesson was to the heart rate monitor. In my case it was the mid 90s and a Polar HRM. So now I could match perceived exertion against both time and distance, as well as estimate my caloric budget. It again made me ride, just to get data. Bizarre, I know. I wanted to exceed 200bpm on my local tough climb and set ever higher averages, so again I could go 'wow, that was a tough ride'.
Which brings me to my newest desire: power measurement. Up to now I've calculated it after the ride, inexactly, and longed to know how many Watts it really took to ride that hard crit. SRMs, offering measurement at the crank seemed a great option. But SRMs were (and remain) waaay too expensive, especially now I had kids to feed. The hub-based CycleOps option was still a bit rich (and what if I swapped wheels?) and Ergomo Pro was again a tad exxy and suffered (like the SRM) from being integrated into the bike. The Polar option was both expensive and tricky to set up. So I looked at the next-best options - the German HAC4 and other options from Germany and Italy, which calculated power from time, speed and altitude gain using accelerometers or barometric changes. Of course this only works on hills, but it was an option. Some of these options don't offer download, so it would be a 'write down later' sort of thing - like back to the 80s.
The HAC4 looks great options-wise but is a bit expensive compared with low-end 'real' power meters. I also looked at GPS units like Garmin's and wondered why no-one had integrated the coolest features into one unit. Maybe one day, I guess.
Anyway, I flipped a coin and went with the simplest, cheapest real-time data logging power meter I could find. The ibike. It back-calculates power by measuring the opposing forces - wind, friction and inclination - and comparing it to real speed (using a magnetic pickup). Easy to fit, easy to use. It looks the goods but does rely upon (a) your calibration accuracy and (b) unimpeded airflow. Which is to say that it misreads power if you aren't good at entering data (weight, aerodynamic and friction data, basically, although the latter is derived by the "coasting" test) or have impeded airflow (in a bunch, maybe, and certainly in a sharp corner).
I ummed and ahhed about this for weeks (whilst watching the Aussie to $US exchange rate fluctuate, too) and wondered if I really needed to spend $A580 on a gadget. I decided it was now or never and pressed the "buy" button in the ibike website. I'll tell you more later...
In the 1980s I found myself with electronic assistance in my data habit: a cycle 'computer', although all it really did was count wheel revs using a magnet and show elapsed time. It did allow me to see my current and average velocity, rather than doing the usual sums at home after the ride. And it was more accurate than some of the guesstimates I had to make. Now that sort of technology got a bit better over the last 25 years or so, but essentially remains as it was: a bunch of data based on wheel rotation over time, displayed on an LCD. (Although some of these new options are very sophisticated: check out BikeBrain for example)
Now this did make me ride for longer distances, and do more miles each week, as I could actually and accurately see when I had slacked off. And being data-obsessed I just wanted to push teh totals ever higher. Funnily enough I still had to chase down attacks, stick with the peleton over varying terrain and avoid being dropped, irrespective of what the displayed velocity was. But now I could also go 'ah, look at that average' after a hard crit.
The next leap forward in this history lesson was to the heart rate monitor. In my case it was the mid 90s and a Polar HRM. So now I could match perceived exertion against both time and distance, as well as estimate my caloric budget. It again made me ride, just to get data. Bizarre, I know. I wanted to exceed 200bpm on my local tough climb and set ever higher averages, so again I could go 'wow, that was a tough ride'.
Which brings me to my newest desire: power measurement. Up to now I've calculated it after the ride, inexactly, and longed to know how many Watts it really took to ride that hard crit. SRMs, offering measurement at the crank seemed a great option. But SRMs were (and remain) waaay too expensive, especially now I had kids to feed. The hub-based CycleOps option was still a bit rich (and what if I swapped wheels?) and Ergomo Pro was again a tad exxy and suffered (like the SRM) from being integrated into the bike. The Polar option was both expensive and tricky to set up. So I looked at the next-best options - the German HAC4 and other options from Germany and Italy, which calculated power from time, speed and altitude gain using accelerometers or barometric changes. Of course this only works on hills, but it was an option. Some of these options don't offer download, so it would be a 'write down later' sort of thing - like back to the 80s.
The HAC4 looks great options-wise but is a bit expensive compared with low-end 'real' power meters. I also looked at GPS units like Garmin's and wondered why no-one had integrated the coolest features into one unit. Maybe one day, I guess.
Anyway, I flipped a coin and went with the simplest, cheapest real-time data logging power meter I could find. The ibike. It back-calculates power by measuring the opposing forces - wind, friction and inclination - and comparing it to real speed (using a magnetic pickup). Easy to fit, easy to use. It looks the goods but does rely upon (a) your calibration accuracy and (b) unimpeded airflow. Which is to say that it misreads power if you aren't good at entering data (weight, aerodynamic and friction data, basically, although the latter is derived by the "coasting" test) or have impeded airflow (in a bunch, maybe, and certainly in a sharp corner).
I ummed and ahhed about this for weeks (whilst watching the Aussie to $US exchange rate fluctuate, too) and wondered if I really needed to spend $A580 on a gadget. I decided it was now or never and pressed the "buy" button in the ibike website. I'll tell you more later...
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