New TT application for iBike

[turbomentor]

Howdy everyone.

I've been bugging Velocomp about this for a while, so it's only fair that he made me do the testing!

I'm riding the prototype of the wind port adapter.
Click on this URL to go to my Facebook page to see pics of how it looks and how I set it up. http://www.facebook.com/album.php?aid=6 ... 91f0ce7d2b

Click on this URL to go to Training Peaks for a graphical view of my second test ride (tonight)http://www.trainingpeaks.com/sw/RU35RM5 ... IKY5GBP4KY

I installed the adapter yesterday on my bike and did about an hour test ride. I did not have time to do a new profile, so I rode with the profile that I already had in my bike. Also, I've recently made some pretty radical changes to my TT bike in search of a better position; raised the seat 1.5 cm, brought the seat forward about 2.75 cm and removed about 3cm of spacers on the steer tube. Incidentally, I made all these changes the night before my first triathlon of the season and ended up running the fastest 10k triathlon I've ever done.

In any case, tonight I took the time to do a calibration ride. Luckily, I had my laptop with me at the beach, so I returned to my car (the mobile speed lab as I call it!) and downloaded the cal ride to IB3, then uploaded the profile to my iAero.

I then did an FTP test for myself. The coaching I use calls for 20' as hard as possible, 2' rest then another 20' as hard as possible. Take the NP for that time and that is considered your FTP for training purposes. The ride file is attached to this post. I will post more ride files as they become available (I ride a lot!)

My impressions are that the alternate wind port actually improves the functionality of the iBike. It isolates the wind port and provides the most "clean" air flow possible...thus my wind scaling factor was nice and low. Of course, over time I will probably refine my Crr and CdA numbers, but there was no difference in setting up the iBike with the alternate air port. My first interval showed 255W on my PowerTap, iBike showed 260W. The second interval showed 253W on my Powertap, iBike showed 250. For an athlete like me (primarily long course triathlons) I cannot see how that wattage difference is consequential. Pavg for the ride was 236 vs 231 (PT vs iBike). Again, completely inconsequenntial. This was my first test ride with a brand new profile that I have not tweaked at all.

For any time trialists and especially triathletes who tend to have an aero drink system mounted twixt their aerobars, this will make the iBike usable as you can put the wind port anywhere you like. For roadies, I think this is a great way to get improved functionality out of your iBike.

Velocomp is goinng to begin producing these adapters soon. Again, I will provide more test data as I get it.

[turbomentor]

Graphical view of PT vs iAero with the new wind adapter.

Happy to answer anyone's questions. More graphs as I do more rides.

[pjboyle]

I am intrigued by this setup even though I do not have a TT bike. I can see this having applicability for a road bike on a rainy ride. You would not need as much tubing as this, you would just need enough downward slope of the tube to prevent rain water from being forced up the tube for ingestion by the unit. I have had this problem several times while riding in Louisiana rains.

PJBoyle

[turbomentor]

That sounds like a great way to use this device.

Even if it's not raining, I think the wind scoop helps give the iBike better data. The wind scaling factor was a lot better, feeding the iBike better data to create a more accurate profile, and of course, better ride data.

Hopefully iBike will be able to begin manufacturing them soon.

[samisrour]

Why did you use such a long tube, & where is the tube opening? are you using a funnel opening at the intake end of the tube?

It does not make sense to me that this setup would function, because I thought the air intake on the IAero operates on the ram air principle, such as a pitot tube on an airplane.

I am somewhat in disbelief & amazed at the consistency of the numbers, between the IAero & on the Powertap. Can you post the file that superimposes the Ibike & powertap wattage figures?

[coachboyd]

Here is a file from when we made the first beta prototype of the pitot tube. This was the trial run that made us go ahead and go with this idea as a solution for time trial applications. When you see the slope go up and then down that is the high point of my week in Boca Raton. . .a bridge. I got out of the aero bars and then back in the aero position after the downhill.

I had the live cda feature on and it was great to see in action. I lost three seconds in the 4 miles until I made the turn, then climbing out of the saddle I lost some time, but gained it back on the return trip when I was trying to get as aero as possible.

[samisrour]

Hi Boyd, If you go to the power meter comparisons menu, You will see that there is a diferece of Plus 35 aprox & minus 75 aprox.

Can you explain the huge difference in the 2 power meter readings?

Sami Srour

[coachboyd]

No two power meters will agree with each other 100% of the time. I have ridden with Quarq and power tap at the same time and seen bigger differences that I usually see comparing my iBike to other power meters.

[samisrour]

I agree with difference in power meters. In this file a 75 watts difference is approaching 50% difference. Power tap claims 1% & SRM about 1%. but 50% difference between a powertap & the Iaero is unacceptable, don't you agree? there is something wrong with one the power generated in this file. Could it be the pitot tube, or the pressure sensor intermittently inoperative in this situation?

Sami Srour

[coachboyd]

If you look here http://www.ibikesports.com/documents/Jo ... alysis.pdf
as well as some of the other rides I do, you will see a 75 or more watt difference at different times during the ride between a power tap and a Quarq. And if I could have put an SRM on the bike at the same time, there are times when that would have read different than the others.

Power tap and SRM may both claim accuracy within a couple percent, but they don't guarantee that accuracy every second of the ride. . .neither do we. The most important thing with power training is repeatable results with raising your wattage over specific time periods. The iBike has shown to do that just as well as power meters costing thousands of dollars more.

[Velocomp]

The iBike and PT have different filtering of the power data. PT data tends to be more "spikey" than iBike data, causing the apparent differences. If you look at the Power Meter Comparision data with no filtering applied, you'll see that when cadence increases from zero, the unfiltered data of the PT jumps faster than the iBike data, causing the wattage differences. I've attached an image showing one example of this. At mile 0.33, there is a 300W difference between the two PMs for an instant.

Signal filtering is a complex subject because the filters themselves can introduce erroneous data overshoots; the faster the transient response, the more likely it is that the filter will overshoot the mark. We don't know what filters PT uses but we elected to use a filter that would result in smoother watts readings. This is why our filter is not as "fast".

These two PMs line up extremely well in this ride!

[Norm]

Will the wind scaling have to be reset when using the alternate wind port or is it a "plug it in and ride" kind of modification?

[Velocomp]

You'll need to do a new Cal Ride with the Remote Wind Sensor.

The RWS is now available for pre-order at the iBike Store.

[Morocco Mole]

Question about the remote wind sensor, once it is mounted does it impeed removal of the iBike, or is it simple to disconnect from the front of the airport?

[samisrour]

Will the remote wind sensor be removed out of the head unit & placed in the tubing somewhere?

[cjonbike]

The remote wind sensor is just a fitting that is placed in the wind sensor port on the iBike with a tube connected to it that you run somewhere that has a free path to the open air with a wind scoop on the other end to better catch the moving air. The wind sensor itself is still in the iBike

Chris

[Velocomp]

You can see an image of the RWS at the iBike Store.

[turbomentor]

Question about the remote wind sensor, once it is mounted does it impeed removal of the iBike, or is it simple to disconnect from the front of the airport?

The RWS is simply a piece of resin that plugs into the front of the iBike. It can be connected or disconnected at will. It is as easy as plugging in something into an electrical socket.

[turbomentor]

You can see an image of the RWS at the iBike Store.

The first posting in this thread also contains a link to my facebook photo album showing my RWS setup.

[cghebert]

Are you just using a standard stem mount for your setup? I currently have the Xtender so my iBike sits below my aero bars. However, moving it up out of the wind - and where I can see it properly - would be nice. I figure if I wanted to move it though I would need both the RWS kit and a stem mount. Is there a wired stem mount or a simple way to alter my standard mount into a stem mount?