Showing posts with label ibike. Show all posts
Showing posts with label ibike. Show all posts

Thursday, July 15, 2010

I use an Elite mag trainer but the Wattbike seems to be a well thought out indoor cycling tool

I've chewed up a few tyres on a range of trainers, the last couple being fairly standard Elite units. I think the first indoor trainer I tried was in the mid-'80s and was called a 'Racermate' or similar. It was a wind trainer with a finned 'fan' at the back. It wore out both rear tyres and itself, but I kept it going for maybe 10 years all up before moving to an Elite mag unit. I sweat copiously and am not afraid of a 1 hour session - my all-time record on one of these things is 100km - and every unit seems inevitably to rust. Not to mention the bike, too. I've tended to use either sacrificial "retired" steel bikes or newer aluminium ones and catch the sweat with a towel. I've tried a fan but prefer a "semi-outdoor" airy under-the-back-deck location. And I use an ibike power meter these days to capture some data from that spinning rear wheel. Whilst it all works OK, there are better indoor trainers with bigger flywheels out there these days. And really, nothing really beats riding on the road.

But maybe the latest crop of indoor trainers, including the interesting LeMond creation (which ditches the rear wheel entirely) will tempt me. The fancy Wattbike has also caught my eye...  not that I can justify the expense!

Wattbike Polar View - Wattbike
When cycling, you can play around with the graph – pushing on the left leg will create a large force shape on the left, pushing hard on the right leg will enlarge the graph on the right. You see a percentage beneath each side, telling you how much power each leg is generating. Standing up and altering your cycling technique will produce a change in the graph.


Saturday, June 26, 2010

It was inevitable - iPhone + iBike = iBike Dash

If I could stomach paying through the nose for an iPhone this would be a convincing combination. The iPhone has the hardware needed, just add the iBike software for the most complete GPS and power 'bike computer' you could imagine. Allowing for the fact that it still back-calculates power from measured variables of course. Still brilliant. Oh yeah, I own an iBike, but no I won't be buying an iPhone just because it's funky.   

iBike Dash Cycling Computer | iBike Dash + Power
Expertly equipped with both the revolutionary cycling computer functions of the iBike Dash and the next generation of power measurement technology of the iBike power meter line, the iBike Dash + Power is the ultimate control panel for those who take their cycling and cycling fitness seriously.
Learn More


Monday, April 06, 2009

Gosford hillclimbs: Avoca to Kincumber 182W 12.3 pc

Did this a few months ago, but in an idle moment thought I'd post it now.... part of my plan to run my ibike wattmeter over all the local hills around Gosford, NSW.

The iBike calculates Watts from changes in speed, altitude (via a barometer) and acceleration. Whilst the numbers aren't large (I'm not Lance Armstrong) It gives me some way of baselining my training and working forward.

These aren't necessarily my best rides, highest speeds or biggest Wattage - just representative screenshots to give you an idea of hill slope and shape. If you don't have this sort of equipment you may find it interesting or useful.

Tuesday, March 11, 2008

iBike and Garmin GPS wireless now integrated

I'm still testing the iBike, but it's almost 1 year on and I'm still happy. I'm prompted to write this by an ibike announcement - they now have some new firmware that allows the iBike wireless model (the one I don't have) to integrate wirelessly with the Garmin GPS-enabled devices. So you end up with location and power on the one sweet load of data. Beautiful. I can imagine it - and it looks fantastic - but I'll pretend I don't really need it for now. But if you are buying a new one, go wireless!

Just to update you, the v1.16 firmware has extended battery life enormously, by around 2x at least. Winter will be a truer test (it's just gone autumn here), but I suspect that battery life is no longer an issue.

And of course don't believe the latest issue of Ride magazine, which still believes that ibike is for moving bikes only, not for stationary trainers. In fact there are a number of pre-calculated and approved indoor trainers for which the ibike is individually mapped and (apparently, as I haven't tested it yet - another reason to go wireless I guess) works. Check it out at ibike: We’re taking it off the streets with the new iBike Pro Indoor Trainer. This purchasable iBike Pro firmware upgrade, used in conjunction with the iBike Wireless Heart Rate mount, makes it possible to use the iBike Pro to measure power on commonly available indoor trainers. Please include your iBike Pro serial number in the Special Instructions section of your ordering screen when you place your order as the firmware is secured for your individual iBike. Available 11/15/07.

Friday, January 18, 2008

ibike crit overview - with pics

Yeah, ok, it's D-grade but every race is as hard as you make it, or as hard as that guy who should go up a grade makes it, anyway. So here are some pics to show you what the new ibike2 software is like... Straight below is an overview of the new data display. You get a detailed data summary on the top left, now including some aero values you can plug into other software for comparison, or to take away and tweak. You also get a useful tool for analysing the data, setting barometric pressure and adjusting your 'coast-down' values post-ride. So you can load old rides and update the ibike values, for example, if you have adjusted 'em. It gives you more control over the results. The blue area is the crit last week. The rest is pre-race warmup and post-race cool-down. Top-most graph is power in Watts. Next is speed, then elevation and last of all slope. You can see from elevation that there's a hill each lap... and you can move the cursor to any point and get power, speed and elevation data at that point.
And this is the power peak in close up. Along the bottom of the display you see the data on the cursor: 752W, 35.9kmh, 3.8% slope. If you run those numbers through your calculator (plus weight, temp, barometer, elevation, headwind, all available from the ibike) you'll verify that's pretty darn close. The only real problem is when you hit the 'go' button too hard on a climb and lift the front wheel. You can easily turn 3.8 degrees into 4.5, or more, and get a huge - and inaccurate - power reading. But you can fix that any number of ways, too. Especially if you ride the same hill a few times and know the slope doesn't exceed 4.5%, for example.
Last for today - this is a closeup on the velocity peak. Speed maxed out in the sprint at a lowly 49.1km/h, best so far being over 55kmh, but it was into a headwind this time, and I managed to pick the wrong wheel to follow, too. So I ended up in front too early. Still, you can see the power peak on the hill just prior to the downhill sprint - basically where the last attack went. We continued at good speed until the 90 degree left turn but power is down because I'm on a wheel and we are dropping elevation. Someone starts the sprint, I chase, catch and get marooned. Ooops. You can see the sprint power is 529W and the wind has increased markedly after the left-turn.

True, it doesn't tell you anything that you couldn't have worked out anyway, but it puts it right in your face -up in lights. 3 races documented so far and I know how critical that hill is - it's where most attacks start, especially on the last lap. I can see exactly what power I need to generate to match those attacks, and I can see how important it is to stay calm, hang onto a wheel and don't go too early in the sprint, especially if it's windy! And I can take this data away, find a similar hill and practice putting out 700W+ intervals. I could tailor a 'crit simulation' session around this data and see what works. I may find that those steep, medium-power intervals don't help me in crits and that I need to do more snappy, higher power efforts over shorter distances. And so on.

You can do it by feel, or you can buy a power meter and 'prove' your theories. It's up to you.

Saturday, January 12, 2008

Worked hard for a tough 2nd place

Yeah, right. A tough D-grade crit. Riiiight. Well after 2x 1st places in a row I was hungry for a 2nd place this time and did a lot more work at the front. And this time I'll show you the pictures. If you are using Firefox this will work fine, but MS Internet Explorer usually goes haywire and wrecks my layout. Well I use Firefox and I don't care.Firstly, my spreadsheet view of the race data. Basically I took the ibike data from the .csv file and poured it into my own spreadsheet. It gives me max power, average power, mean, average minus zeros, average in power bands, max watts/kilogram, VAM, average and max speed, average and max inclination... I think you get the picture. The normalisation is my own formula (changed once again - it's an evolving beast).

OK, yes, 31.1kmh is a slow average. There was headwind down the short straight and a 4.5% hill each 2km lap, though. It was the slowest of my 3 'comeback' races, but I did more work, too. Average was 155W but if you discount the zeroes (ie drafting, coasting) it was 170W. If you believe in my new normalisation formula it was 234, a dubious measure but the highest race figure so far (at least I can agree with that, it felt like the biggest effort).

The sprint was again in 2 parts: the attack up the hill was the Wattage peak, followed by a slowish downhill sprint into a headwind. I lacked punch and when I caught the breeze I stagnated... but held onto 2nd, anyway.

Wednesday, January 09, 2008

Yeah OK, another win

I managed to win the local crit again - yes folks, D-grade. Well I had to work at it! I had to avoid falling (one rider down as a faster grade caught us on a corner - nasty!) and I had to watch for breaks (just one semi-serious attempt, easily caught). And I had to patiently wait for the impetuous youngster to start the sprint.

More importantly it gave me more race data. So I can confirm that last week's 1400W burst was indeed an error on the ibike's part, as expected. I'll show you the data later but every lap we went over a small hill, and each lap the hill got steeper. Or so the ibike thought. When 'corrected' it's still a 900W effort (bridging a last-lap gap). This week's data is much more consistent and the peak power a more miserly 800W. I was careful not to expend too much energy in short bursts, rather I anticipated accelerations and smoothly bridged. Each lap the hill registered between 300 and 5ooW effort and 42% of the race was above 200W. If you trust the ibike, of course!

It's a slightly downhill sprint so although I briefly hit 55kmh the power was just on 600W.

I have upgraded to ibike firware v1.16. I always reset after a ride and do a re-tilt when changing bikes. I have a battery of coast-down data to tap into a well. It's not perfect, it certainly goes awry when the barometer is moving around, and if you lift the bars or otherwise drastically alter your weight distribution during a ride then it can generate some flaky figures... but it works well enough to be a great tool for the data junkie on a budget.

Saturday, December 29, 2007

the race data, of course

A win is nothing without data, eh?

OK, D-grade crits at the CCCC are short - 30mins plus a lap (another 2km, so about 16-17km). We start with the "D1" kids and drop 'em off after 2 or 3 laps, so we start slow, slow but then speed up. It was 32 degrees Celsius off the tar at 6pm - hot. And the wind was 30kmh from the NE. I was on the Felt F-50.

I dump my ibike data into a spreadsheet, so it comes out like this:
MAX power
1447W
MEDIAN 68.5W
AV (all)
104W
AVERAGE (>0W)
151W
TRIMMEAN (10%)
88W
Normalised
296W
Max power is peak power. With the ibike it's susceptible to lifting wheels, and the combination of pulling up on the bars on an 8% hill during a max effort bridge to the attacker probably distorted the real power... so let's say it was 1,000W anyway, if not 1,400.

The all-up average treats coasting as part of the race, hence Av (all) is just 104W but (Average (>0W) removes all zeroes... which is more 'real'. 151W still sounds low - but we did start slow!!

That's my own normalisation formula, by the way, and definitely a WIP. As a relative measure it gives me a way to judge between efforts. It emphasises the middle over the high-end of the power output range and tries to indicate real effort - all soft-pedalling or coasting is removed and we are looking at just the real "training" load, but I haven't yet perfected a way to recognise effort over time... so short rides are favoured over long ones. I'm working on it.
600-700W 0.15%
500-600W 0.46%
400-500W 2.49%
300-400W 7.02%
200-300W 12.57%
100-200W 32.88%
0-100W 43.51%
This breaks-down the power into steps. I can see that 43% of my race was coasting or drafting (0-100W). When training I seek to minimise this figure, to actively eliminate those slack periods, In a race I take full advantage of these "rests".

You can also see that there were only a few 600W+ efforts, and the 300 and 400W steps represent the once-per-lap climbs. Knowing all of this allows me to finetune my training to meet my race needs, although C-grade may well be more "attacking" and both the averages and the peaks will be higher (and more frequent in terms of peaks).
695 VAM (max)/hr
10.5 Slope % (max)
-0.44 Slope % (average)
32 ALTITUDE (max)


50.53 VELOCITY (max)


25.0 VELOCITY (average)

The VAM is useless - not enough hills! But the 50.53kmh peak velocity in the sprint in useful. The 25kmh average is misleading as it covers 20km - warm-up, race and cool-down. The race itself averaged 32kmh (slow, I know, don't rub it in).

Tuesday, November 20, 2007

ibike update worth it

OK, so I use an ibike and have whinged a bit about some niggles. Well Velocomp has seemingly fixed all of those issues - and brought the ibike up another level.

For completeness here's a long post that covers just about everything I've ever written about the ibike and briefly describes ibike 2.0. I'll say more about ibike 2.0 soon.

The ibike and me.

OK, I'm a bike rider and a data collector. I have documented every ride I've ever ridden, and the data keeps getting better as the gadgets improve. Hey, it works for obsessive old me. Simple bike computers are great and tell you a lot. But maybe you want to measure your power output as well? This post focuses on the ibike power meter - what it does, how to set it up and the problems you may encounter - but covers a bit of bike computer history as well.

But first, the latest update!

Just a quick note about the latest ibike upgrade. It's a significant change. Firstly ibike release 1.15 upgrades the ibike unit itself to accept new features, including wireless sensors and - a big one - the use of indoor trainers. Going wireless is not only neater and easier to install but the battery lasts longer as well. Currently I get a couple of weeks out of the CR2032 battery - up to 3 - riding 7-10 hours a week. You can stretch it to 4 but the readings get dodgy. Wireless looks like a good option if you have battery problems (colder climates especially seem to reduce battery life).

Secondly the ibike 2.0 software is a massive improvement. Now you can process multiple coast downs and calibrate against a 6km ride. You can adjust - tweak, if you like - the aero and friction values to your heart's content and apply these new settings - or a bunch of different profiles if you want - after the ride. So you can forget to change profiles when you change bikes and it doesn't matter. You simply apply another profile in the software and save it.

The calibration tools are much, much better. You can also adjust barometric pressure and temperature. All in all a great upgrade for the technically minded, although the casual user may be put off at first by the greater range of options.

Power overview

OK, so you want POWER? You want to train harder, or better? Or you just want to see how many Watts it takes to ride up that hill? The ibike may be just what you want - it was what I wanted, and here I will tell you all about the tips, trips and fun I've had measuring my Wattage as I ride!!

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... drats, 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! What about the software?

First up, read the update above - things have improved. For teh record, here's how I found ibike 1.0 - and ibike 2.0 has installed over the top faultlessly.

Well the v1.0 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. Check this out...

The 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! Did you check this out...?

Mounting ibike on the bike

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. Hmmm, this again...

The purchase experience

OK, so I chose to buy 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 $Aussie 600/ $US450 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!Don't forget to check this out...

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...

Wednesday, July 25, 2007

iBike update (again)

You remember I bought an iBike? How could you forget?

You can search this blog and find the whole story but in short it's a one-wire, one-external-sensor black box (it's actually white) that uses variables like velocity, acceleration and altitude change coupled with your own choice of constants (weight, friction and aerodynamic co-efficients) to calculate power. It dumps all of that data into a reader and you can play with the .CSV file in any spreadsheet.
  • The pros are that it's the cheapest option for constant (ie not just hills) power measurement and it's as easy to mount as a speedo (making it easy to swap bikes, too).
  • The cons are that the constants aren't really constant. Your weight changes as you sweat and eat (but not by much, unless you are riding 200km/day and not refueling); your aerodynamics change as you sit up or crouch down (but you can adjust your aerodynamic constant to be a 'best fit' for your needs), or just sit in a draft (and yes, it does give some strange results when drafting big bunches or trucks). And your friction changes according to tyre pressure and road surface (but again, not by much).
So it simply can't compete for spot-on, every-day accuracy with SRM or PowerTap, but beats both on price. And if you are prepared to accept and work around the cons then it's still a remarkably useful device for training. After trying all of the 'tweaking' options I've settled on a 'best practices' guide that works for me. I'll share that soon, but here are some tips:
  • Batteries... buy a few CR2032's for spares... they can last a 2 months or 2 weeks, depending upon sample rate and time on each ride
  • Some batteries drop below the recommended 2.75V on ride 2 - but bounce back on ride 3! So don't chuck it away too smartly
  • But be careful, too, as you risk losing all ride data and probably getting spurious results with a low battery, but...
  • I've had no obvious problem starting a 1-2 hour ride with voltages as low as 2.66V.. and it even ended the ride back at 2.72V

More later!

Friday, May 25, 2007

Power meters.. the ibike again

OK, an iBike update, firstly. The 3V battery dropped below the recommended 2.75V so I swapped in a new one. First battery had lasted for about 26 average 1-hour rides, or about 40 days. I used the "coast" function about 7 times. Maybe 6 rides were about 90 minutes. The new battery lasted 2 whole rides (and 3 "coast" tests) before dropping below 2.75V! Aaaargh. I rode yesterday and today with the battery below the minimum and the results are fine, so I guess there's a margin for error here (if you start below 2.75V and ride for 6 hours I'd guess you may lose some data, or get screwy data). Now I know why iBike sell batteries in bags of 20!

I also filled the memory once and have taken to dumping the ride list more often. The unit is still reliable but when analysing the data I suspect (and I cannot prove this) that it:
  • undervalues flat-land efforts by 20-50W (ie shows 150-180W when my manual calculations suggest 200W is closer)
  • overvalues sprints by a considerable amount - as much as 50% higher (ie shows 1500W when manual calculations point to maybe 1000W) but only for a second or 2
  • is most accurate at sustained high or medium-effort climbs, where the output is often within 2-5W of manual calculations based on speed, time and inclination
  • lags the actual effort by 10-30 seconds
  • loses it's pretty little head in corners and over bad bumps.
Now that reads pretty bad, but it's not so bad, really because you can:
  • smooth your data and remove 'outliers' such as spurious high-Watt readings
  • normalise your data in a spreadsheet or online tool
  • fine tune your friction and aero values on the provided USB-link software - this is better than re-doing the "coast" setup, I reckon, but it just may be that I've never done the 'coast' correctly (hmmmm...)
  • ride on smooth roads and never go around corners.
OK, I'm kidding with the last bit. Overall the data is consistent and relative to the values entered and it remains a useful training tool at a great price.

Some other quirks are:
  • It alters altitude overnight - presumably as the barometer rises and falls - so adjusting it is a good idea fi you want your data to be consistent
  • It adds 100kg (or maybe just defaults to a really high weight) when you swap batteries - make sure you check your setup after changing batteries!
If I hadn't bought the iBike (and I don't regret it, BTW, if only because it's still the easiest and least-cost way to get into full-function power meters) I would have considered Polar's new CS600 with power reading. It looks like a real hassle to fit but at least is wheel-independent and would work on an indoor trainer (which alas iBike can't - as yet - do). Pez has a good, detailed review of the CS600 here.

Wednesday, May 09, 2007

update on iBike test...

It's a real-world test, in that I actually bought one! So how's it going?

Well for around $US400 from iBike itself it's a bargain, so you'd allow for some rough edges. But so far it hasn't shown too many. Get it set up right (it's not hard to do) and allow for its obvious limitations (such as it relies on barometric measurements of air pressure coming in through that little slot in front, so anything that distorts airflow - like turning sharp corners, sudden dips or objects blocking the air intake - will also distort the power calculations. And of course it won't work on an indoor trainer... yet) and it's a powerful tool that gives accurate figures. I have back calculated and verified my iBike data against some basic, manual calculations and it falls within a few percent of what I'd expect, given speed, weight and inclination (that's hill slope, not my inclination).

It has given some doubtful results that appear as spikes in the data. I've seen 1495W once in a sprint - possible but I thought unlikely. I calculated it was closer to 750-800W, so manipulating the .CSV file eliminates that spike. I have since then sprinted at a maximum (and believable) 800-1000W many times with just one other sprint appearing doubtful at 1466W. I had already re-done the "coast" test because of the 1495W spike, and I'm confident that the coast-down is now correct. So either I really did put out 1466W for a second or there's something else going on. Strangely enough both spikes were in the same location... like exactly in the same spot. I'm thinking there's a dip in road or some other strange factor I'm missing here...

So out of over 500km of testing it's so far given me 2x 1-second spikes of doubtful data. The rest of the data looks good, with a steady improvement in wattage from an average of 168 over about 45 minutes to the current best of 210W for 60mins. When I remove the "zeroes" from the data it "normalises" to 230W over 1 hour (and 220W over 90minutes). Given that I'm not racing at the moment (which I imagine would lift those figures substantially) I'm satisfied that the iBike is working and also that training-by-power is effective - if only because it has re-motivated me!

More soon...

Friday, May 04, 2007

More on power

As I've mentioned, I bought an iBike to assess my current (low!) power and to try to lift it. I lament that I didn't have such a device when I was 29, but hey, now I'm 49 and I have one. So as a data junkie I am in now in heaven. Early results are positive (still on same battery after 4 weeks, filled the data log after less then 3 weeks) and the data looks good, if a tad low. It was originally too high, so I re-ran the "coast" test until it looked right. Now I worry if it's too low but hey, it's all relative, so I'll leave it as is for a while.

Some thoughts:
  • too many "zeros" will lower your average power. By simply minimising my freewheeling I have cut the zeros from around 12% to under 8%. Alternatively you can just remove those zeroes from the CSV file in a spreadsheet
  • So I began around 168W average and now have it up to 190W average (over an hour). Removing all of that freewheeling has helped but I am also getting fitter and stronger
  • My peaks have declined from over 900W to low 800W but my 20 minute average is up from 230 to 290W
  • So is it still making sense?
What is the norm for a nearly 50 year old racing cyclist who hasn't raced for a couple of months, but who has a 35 year history of riding and racing? I did find this interesting chart:

Men Averages



Measurement

Value

Average Age (yr)

38.9

Average Weight (lb)

175.9

Average Body Fat

16.7%

Average BMI

25.3

Estimated VO2 Max (ml/kg/min)

55.3

Average Wmax (Watts)

346

Av Power-to-Weight Index @ Wmax (W/kg)

4.4

Av Lactate Threshold Heart Rate (bpm)

167

Average VO2 @ LT (ml/kg/min)

43.6

Average LT percentage of VO2 Max

79.1%

Average WLT (Watts)

267

Av Power-to-Weight Index @ WLT (W/kg)

3.3

Average WLT percentage of Wmax

77.2%

Average Power @ 12 seconds (Watts)

666

Av Power-to-Weight Index @ CP0.2

8.3

Average Power @ 1 minute (Watts)

482

Average Power @ 6 minutes (Watts)

316

Average Power @ 30 minutes (Watts)

267

Average Cadence (rpm)

92.0

Which at least suggests I'm in the ballpark... hope you find power training useful. I guess I'll have to test it out in a race soon...

Saturday, April 28, 2007

A wrap-up of results and stuff...

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.

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!

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.

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!

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.

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!

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...