AeroPod, PowerPod and Newton

Recently I bought an Isport to get an first impression of riding and training with an Power Meter. As I already owned an Garmin Edge 500, I use this device to record the powerdata and load it into WKO+. This all seems to work pretty wel, allthough I was pretty suprised to see for instance that my 5 sec numbers where in the: untrained cat. and my other numbers weren't quite as expected either, but humble as I am I thought I was just not as good as I thought I were. My max output for 5 sec was somewhere around 800 or so which put me in the bottom of untrainend, no I'm not that much of an sprinter and more an type of rider who likes to take long climbs at one pace, but serious: In the bottom of untrained...

As I recorded more rides, I suddenly had one 1316 watt output for the five second interval, and that ride was on the same criterium track as other recorded rides which gave my maximum numbers in the 800's on comparing, and judging frame cadence and speed, probally much harder rides, that made me look more better at the graphs and at the Ibike when riding. Today I made an long tour with some intervalls in it and hammered up some slopes to get the numbers up butt when I'm out of the saddle for the first part of the 'sprint' the Ibike reades: 0 for a few seconds, guess the most power is being produced in that critical first part of the sprint and therefor making these numbers useless. As it happened every time when I came out of the saddle and pushed it hard, while swaying my handle bar, I figured it might be due to this swaying motion of the handlebar that the Ibike gettes confused, after I tried some 'sprints' in a complete straight line and while remaining in the saddle I was able to get the numbers up to around the 1300+ again. As I also get a few second of zero's after taking fast turns on criteriums turns, while allready putting the power on the pedals again, I believe there is an slight problem with useing the Ibike in non-horizontal positions, and due to this problem making the avg. and max numbers not really usefull and thereby making the device not so usefull to use as an training aid.

What I also notticed is that when ridding on an bumpy road, just bricks no way near to cobbels, the power output falls back aswell, I was doing 40 km/h and when I hit a small strech of 400 meters of this kind of road the output fell back pretty fast from 400 to 200 and then to 100 and eventually back to 0 in the timespan of 3 seconds, this while still remaining an speed of around 40 km/h and roughly the same cadence, needless to say this 400 meter period 0 made my efford of an long 400+ watt registration useless.

I've trained a lot to get my cadence up, as an result i'm always aroudn 95 rpm, this also shows in the data, when riding on the downslope after an climb I always keep on peddaling to relax my leggs after the the work they just heave done and prepare them for the hard work ahead, I only stop peddaling in steep corners so my pedal won't hit the floor, besides that, I'm a regualar cadence machine, when I look at my custom distribution chart on wko+ I see that i'm somewhere arond 20% of my ride in the 0/20 cadence numbers which seems way to high especially when you take my way of riding into account, and this confirming the registration of 0's where there should have been other numbers recorded.

Are there people here with simular experiences? is it just an set up problem? if so are there people that use an simular combination of devices and don't have these problems? how can I try and make my manner of registration more accurat?

Check that your speed sensor is securely in place. I've found that if mine (a Garmin wireless sensor) is not positioned right it does not detect speed but my Garmin 705 (and I expect the 500 also) then automatically switches to using GPS to determine speed. But the iBike only reads the speed sensor and gets zero so power shows as zero. Same problem can happen with the cadence sensor. Zero cadence gives zero power as the iBike thinks you are coasting.

Thanks for the tip, it sounded logical, but unfortunally it's not what is causing the display of the zero's I have just tried and when inside and stationary the Ibike pickes up the speed of the rotating wheel and therefor it must be something else. Maybe it's the cadence sensor, but it seems pretty far fetched that on two different bikes the exact same problems emerge, but I will test this possibility on my next ride.

I have run some test today to see what could be causing the trouble:

First I thought the registration problem could be caused by locating the Garmin Edge in my back pocket, because two computers on my handlebar doesn't have my preference, so I did three identical rides and try and see what the results would be:

First: Ibike and Edge besides eachother mounted on the handlebar while riding on a road without any mentionable corners: Result Nice power output date on both displays but when I get out of the saddle to really push in a sprint the Ibike power read goes zero, while the cadence and speed is still displayed on both. So when I ended this test drive with an sprint, small gear to big gear and then push it while standing at the end I can see on the downloaded file I get op to 1014 watt and after that my speed is still rising but my power drops to zero Since the cadence is still displayed when riding, but not shown on the downloaded file I think this is due to the fact the Ibike gives an zero power read and so the Edge must conclude from that there is no more cadence.

I did exact simular test with both the edge in an saddle bag and in my back pocket both with the same results as the first test, power read untill getting out of the saddle and then when I do get out of the saddle : Zero.

I thought it might be because of the swaying motion of my handlebar and the way this will affect the intake of air needed for propper calcualtion, so I start wiggle my handlebar while riding in a straight line, sort of like racing cars which are warming up their tires in front of an race, and the result in all three positions: Power dropping to zero while cadence on both the Edge and Ibike are still displayed.

I know I was sort of taking an short cut when trying get an 'cheap' device that would give me an recordable way to analyse my rides so that it's not up to that job in this configuration is okay with me, I took an change and it didn't work out: To bad, but due to the fact that the Ibike Isport only records when in an stable position and gets confused when: Moving the handlebar when for instance in standing sprint, going around corners, riding on less the perfect smooth roades makes it that it can never provide both the propper power output on your maximum, unless you can remaine in an perfect still position while giving it all you got and the output for your avg. is pretty useless aswell because it gives so many zero readings on: less the perfect roades, when going around corners and every single time when you get out of the saddle, when comeing out of corners and pulling yourself back to speed again, so in other words only if you are exclusively going to ride on: long, straight roades without any corners and remain in a still position you'll be able to get same output that you can compare to other rides, but an normal ride will never give an propper indication of what avg. power you can provide.
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With all these flaws the fit test is also nonrelevent, getting so much zero's will mess up your numbers I guess and will make you train far under your potential and way to soft, so what is left is an device that will give you an occasional correct reading, at least I hope so, when riding in an straight line, on an smooth road, when you're not moving around to much.

I'm kind of disapointed in the Ibike, although it still is sort of an nice gadget, and no more then that, because of it flaws I can't really use it to base an training schedule on it, it's nice to see powernumbers that I can sort of pace my training, but for now I think I might be looking elsewhere for some real dependable system. I'm just wondering werther it's just the Isport, or do the same problems also occur with the more expensive models? I'm under the impression that all three systems use the same way to collect the date, are the other ones without these flaws? is upgrading to an Ipro going to make that much of an difference? do other people have simular experiences when it comes to getting a lot of zero's on Isport, Ipro's or Iaero's? is it perhaps an calibration problem, can the current problems be fixed or is this just as good as it gets?

DIMI wrote:Since the cadence is still displayed when riding, but not shown on the downloaded file I think this is due to the fact the Ibike gives an zero power read and so the Edge must conclude from that there is no more cadence.

I've got a similar setup except I'm using a Garmin Edge 705 to record data. The Garmin takes cadence and speed readings directly from the sensors and only takes the power readings from the iBike. Also, the Garmin makes no assumptions on cadence based on power. The iBike however, assumes zero power if no cadence. So if you are downloading the file from the Garmin and it shows zero cadence then the problem is in the cadence sensor.
I've had a similar problem in the past when grinding on the pedals. The extra force moves the crank just enough to put the cadence magnet out of range of the sensor.
Don't know why you are still seeing cadence on the two units when this happens - I can only assume its a bit of latency.

My suggestion: adjust your sensor position or get a stronger cadence magnet.
Also, would help if you can post about your setup. What sort of sensors (wired/wireless, Garmin or iBike); which iBike model and firmware; Garmin firmware version

I hope, but don't really believe, that it is the cadence sensor. I have Ibike mounts on both my racingbike and trainer, in both cases the exact same results.

I'm useing the Isport in combination with an Garmin Edge 500 both latest version on software and firmware, if the problem was only the cadence sensor why give an zero power reading when riding on less then perfectly smooth roads while still displaying cadence? when I do the 'racing car warm up routine' as described in post above the cadence is still displayed but the power display fails. And the cadence drops from around 100 instantly to zero, time after time after time, if it were an crank torque issue you would figure that it must pick up the magnet at least a couple of times and give me an much lower instead of the sudden zero reading i'm currently getting.

I wish I knew what it is, or could find an fixable explanation, but for the time being I think it's a result of the disturbed airintake when moving around the Ibike to much.

Here is the Garmin file, take a note at the point were my speed is still rising and the power and cadence fall back to zero.


http://connect.garmin.com/player/49840829

Like I said, despite what you are seeing on the display, the Garmin is recording zero cadence and it is reading that straight from the cadence sensor and NOT from the iBike. It is only getting the power readings from the iBike. Your log shows clearly, if you go through one step at a time, that cadence drops to zero first then the power drops after that which is what you would expect. You can even see how your cadence starts at about 96 then quickly goes up to 115 then down to 60 then up to 135 then down to 69 so it looks like ts missing every other reading until it gives out. Might not be the cranks bending (it only needs to be a fraction of a millimeter) - could be vibration. Vibration would also explain the problem on rough roads.
The only thing I can't explain is why you still see cadence being displayed while the Garmin logs it as zero. You aren't displaying average cadence by any chance?

Problems with the air intake do not explain the cadence dropping to zero. A loose magnet does.

[Edited to add another thought]
Here's another possibility. When you get out of the saddle to stomp on the pedals are you maybe obstructing the wireless signal from the cadence sensor?