AeroPod, PowerPod and Newton

Richard your always asking for ride data to better analyze different situations.....back at ya. I'd like to see specfic DATA comparing pro vs Aero. I know the claim is a 4x improvement in stability of power drop outs due to vibration (my biggest concern with my ibike pro) can you show side by side outputs of the two units on the same bike - same ride? Thank me latter for giving you an excuse to take a ride!.

dnessner wrote:Richard your always asking for ride data to better analyze different situations.....back at ya. I'd like to see specfic DATA comparing pro vs Aero. I know the claim is a 4x improvement in stability of power drop outs due to vibration (my biggest concern with my ibike pro) can you show side by side outputs of the two units on the same bike - same ride? Thank me latter for giving you an excuse to take a ride!.

I'm running with both types of iBike units--actually 2 Pros and 1 Aero lined up across the bars. And that's not including the PowerTap. Or the Garmin 705. I don't get to use the tops on my bars. (The CinQo prototype that I have been running with until recently is back at QuarQ getting a FW upgrade.) (For whatever it's worth, one of the Pros is on a wireless mount and the other is on a wired mount.) I haven't been having much trouble with drop-outs with either of the Pros on this bike, but here's a ride where each of the Pros had a couple of drop-outs. I have not seen any drop-outs on the iAero for any of my rides yet. This is data from my long ride from last weekend. I had more tilt error on the iAero than normal, but such is life--it gets corrected on the PC.

iBike Pro A advanced tilt window: iBike Pro B advanced tilt window: iAero advanced tilt window: For extra credit, I'll show the power comparison between the iAero and the PowerTap. This is the full ride: And here is a zoom-in on a 5 mile section:

Travis

I see where the aero did a better job of tilt error correction/absorbption. But why would iBike Pro "B" show significantly less wattage? Or am I not reading something correctly?

racerfern wrote:I see where the aero did a better job of tilt error correction/absorbption. But why would iBike Pro "B" show significantly less wattage? Or am I not reading something correctly?

Fernando,

There's a couple of things going on. One of the things that happens in iBike 2 when you go into any of the analysis windows is that it temporarly backs out of subsequent modifications. (Internally, the order of the calculations is the same as the order of the buttons.) This is just an artifact of the calculation engine's design to keep the calculations elastic (you can do the modifications in any order and you can undo them). This is also the reason that in general the statistics that you see in each window for doing the various modifications are different than the stats that you see in the main window.

The other thing that is going on is that the day that I did my calibration rides, I didn't get as good results for that unit and ended up with too small of an aero value. I haven't taken the time to redo the cal rides because I'm waiting for the CinQo to get back to me. To get the best power number out of that B unit I have been going into the "Tweak CdA, Crr, Cm..." window to increase CdA up to where it should be. For this ride, average power ends up being 165.4 W on that unit.

Yet another thing going on with this unit is that I was in too much of a hurry on the day that I installed its mount and didn't do a good job. My bars are not round where this unit has to be placed and I tried building up the bottom of the bar with electrical tape so that the mount would actually have something to bite onto. (Before I did this, the mount wouldn't make contact with the bar even if I screwed it all the way down. The cross-section of the bar looks like an oval.) Anyway, the layers of electrical tape were a bad idea because they "ooze and flow". Over time, I think this unit has starting going nose-down on me and so it is picking up less wind speed than it should.

Ok, so your next question is probably going to be why don't I just fix the wind speed in the wind speed analysis window. Actually, I do, but it is not perfect in this situation. The unit going nose-down on me creates a situation where the wind offset scaling is too low; however, the wind analysis window only modifies the offset. It is really turning the wrong knob in this situation. With that mount turning nose-down on me, the correct thing to do to fix the problem is to redo the calibration ride and I would end up with a WindScaling number that is larger than before. Check that--the proper thing would be to fix the mount to make it rock solid and then redo the cal ride.

So the take-home lessons in all of this is don't use layers of electrical tape under your mount. If your mount changes position significanly, it is important to redo your calibration rides. And finally, the iBike is very accurate if you do a good job setting it up, which I did with 2 of 3 of my units.

Travis

Great work Travis.....thanks for the data. btw....I'm located in Seven Lakes, NC. Any time you want to ride, let me know.

As usual, thanks for an very clear and concise explanation.

dnessner wrote:Great work Travis.....thanks for the data. btw....I'm located in Seven Lakes, NC. Any time you want to ride, let me know.

If I had straightened that ride out, I could have made it to Seven Lakes.