AeroPod, PowerPod and Newton

Hi all - Considering going with the iBike iAero. Currently use a Powertap Pro+ wheelset for both training and racing and throughout the year have had headaches with flats in multiple races (thus losing power measurement) and a busted rim which is still taking up to 5-6 weeks to replace (rim out of stock). The rim came in yesterday, but now it appears the PT has to go back to Saris being only 4 months old as it's not reading/communicating properly. Too much hassle!

A crank-based system is likely out of the question financially, but I do enjoy training with power vs. heart rate. That's where the iBike comes in. I have scoured the web and read all of the positive and negative reviews of the iAero. Other than the perceived hassles of having to do a tilt calc and input rider statistics prior to each ride (the initial calibration stuff doesn't sound that bad since it's done infrequently), the areas where the iBike "seems" to fall a bit short are (1) sudden initial surges (sprinting out of a corner on a crit; (2) gusty crosswinds; and (3) very rough surfaces.

I live and train in Florida where it's flat but can get very windy. So, the wind may be an issue. I do all my M-F training rides solo, when I do my sprints and intervals. All of these rides are on the same 7 mile very smooth paved loop in a wilderness park. Weekend rides are with the club/team on the same route, or solo on the same paved loop utilized during the week. Where I get the most bang for buck from the PM is during the solo rides, so I think given I ride the same roads during these sessions, the issue of rough surfaces and varying environments doesn't apply that much. I am also disciplined enough to do all my intervals in the same position (i.e., I ride about 75% of the time on the hoods), so the issue of changing positions doesn't seem to apply as much. Third, I tend to focus more on my 5 min and 20 min intervals, and from what I gather the iBike is more consistent with other PMs for these longer intervals that for the short, short stuff. I still do sprints and 1 min power intervals, it's just not what I'm good at. So, it would seem the iBike would be OK here for me as well. I could always rent a PT wheel for testing a couple times a year to see improvement in these shorter efforts.

At any rate, sorry for boring you guys, but I am interested in others' thoughts as to any fallacy in my thinking, any reassurance that the iBike can handle these situations, etc.

Finally, I would likely have to sell the PT wheelset to get an iBike, so pairing the two (PT wheels for training, iBike with non-PT race wheels for racing) is likely not an option (though I would appreciate opinions on this approach too as *maybe* I could make the case with the significant other!!).

TIA!!

You reasoning is very sound, you would be a perfect candidate for an iBike. Don't worry about the Wind, once you have a good windscaling number the iBike has no problems under windy conditions. Just keep in mind if you do plan on using a DPFM in the future, even temporarily, you will need the iAero as the iPro does not pair with such devices. It would be nice to keep the PT for a week or two so you can Calibrate your profile with it, it's not 100% necessary but if you have been tracking your TSS etc in WKO+ it will keep things consistent between the 2 power meters. It will also give you confidence in the iBike when you see the comparisons.

Morocco Mole wrote: Don't worry about the Wind, once you have a good windscaling number the iBike has no problems under windy conditions.

I'm curious about your experience with that? IME wind scaling and wind offset are moving targets, plus cross winds can effect the wind sensor a lot.

Some people have reported bad data while standing and rocking the bike back and forth, but I haven't noticed anything there. One thing you might consider is rain... which can result in bad data for most and even failure for a few. The RWS helps with that I hear. Basically, I think the iBike will do what you want.

Yep, rain can be a problem. A couple of weeks ago I rode in steady drizzle/rain, at one stage, I noticed my power numbers much lower than it should've been.

I stopped, removed the iBike from the mount and blew into the wind port to clear out any moisture. Put it back on, did a wind offset and off I went, happy to report that it went back to normal after that.

Temperature is another factor - especially colder, dropping temperature affecting the reported wind speed and thus power readings. By colder temperatures - I am referring to anything below say 10C or so. So, if during a ride, you hit a cold front or noticed temperature dropping a few degrees, it's a good idea to stop and do another wind offset.

I rode in a downpour last week and had a similar experience... I thought. But the next ride I noticed that the numbers were off. Turns out that the wind scaling increased from ~3 to 5 (handlebar mount), and I now have a strong temperature effect where before I didn't. A test showed that if I zeroed at 75 deg, and warmed it up to 115 deg, the wind offset went up to ~+7. Dropping the temp down to 35 resulted in -7. This is a huge effect. Considering that I saw a temperature of 110 on the unit while on a climb with a tailwind, when the outside temperature was 80, it's impossible to compensate. If the sun goes behind a cloud or the wind shifts, the temperature can change a lot.

It doesn't seem right that rain should have a permanent effect on the iBike... but so long as it sort of stays the way it is now, I can adjust the wind scaling easily enough. The temperature effect on the offset is more troubling. A lot of people have mentioned similar issues lately... I think it is time to provide a way for users to adjust this.

rruff wrote:

Morocco Mole wrote: Don't worry about the Wind, once you have a good windscaling number the iBike has no problems under windy conditions.

I'm curious about your experience with that? IME wind scaling and wind offset are moving targets, plus cross winds can effect the wind sensor a lot.

Some people have reported bad data while standing and rocking the bike back and forth, but I haven't noticed anything there. One thing you might consider is rain... which can result in bad data for most and even failure for a few. The RWS helps with that I hear. Basically, I think the iBike will do what you want.

Certainly wind offset will vary, which is why it's important to check it before every ride, even mid ride if conditions change drastically like temperatures drops or rises. Wind scaling should not be an issue though unless you change your position on the bike, a lot of guys move to the drops in windy conditions so I wonder if that is a cause of varying results? Much like the original poster, I pretty much stay on the hoods 100% of the time, especially when performing 5 and 20's . Rain is a whole different matter, agree the RWS would help and also sealing the face with clear tape or Contact, but I don't do intervals\efforts in the rain so not really concerned about accuracy in this conditions.

The point I'm trying to make is that the wind sensor can vary significantly in it's measurement... depending on a variety of factors (wind direction and speed, temperature, and other unknown things). If yours doesn't, then I'm happy for you. The temperature effect alone was causing a change in offset of >5 *during* a ride. You can't stop to adjust it every time the wind shifts or a cloud goes over. Previously I had a unit that would vary this much randomly (ie not based on any variable I could determine) but that one was replaced under warranty.

Oddly, after riding in another downpour the wind-offset temperature dependence seems to have fixed itself... very strange. The same test I performed before (115 deg, 35 deg) and got +-7 Pa change, has dropped to +-1 Pa... like it was originally. I know that VC claims to do temperature compensation at the factory, so did it reset... and then reset back? I hope it stays this way...

rruff wrote:The point I'm trying to make is that the wind sensor can vary significantly in it's measurement... depending on a variety of factors (wind direction and speed, temperature, and other unknown things). If yours doesn't, then I'm happy for you. The temperature effect alone was causing a change in offset of >5 *during* a ride. You can't stop to adjust it every time the wind shifts or a cloud goes over. Previously I had a unit that would vary this much randomly (ie not based on any variable I could determine) but that one was replaced under warranty.

Oddly, after riding in another downpour the wind-offset temperature dependence seems to have fixed itself... very strange. The same test I performed before (115 deg, 35 deg) and got +-7 Pa change, has dropped to +-1 Pa... like it was originally. I know that VC claims to do temperature compensation at the factory, so did it reset... and then reset back? I hope it stays this way...

I check my wind scaling about once a month and it never varies significantly, apart from a once off large change that occurred after the first time I got caught in heavy rain. I have also sealed the face of my unit with Clear Contact and I'm sure that's helps with the consistency, I bet it's something to do with more stable pressure measurements inside the unit.

Thanks for all of the feedback. As it turns out, I may be going the route of keeping the PT wheel and using it for training, and pairing it with the iBike to record data while training, and then using the iBike on it's own on race day with lighter race wheels. Will just have to sell my Garmin Edge 500.

Now the big question is whether to wait for the iDash? I like everything I have read about it, but it looks rather large sitting on the stem and I'm not sure about doing a RR or Crit with it attached, and also about longevity of it if I were to switch phones or Apple was to redesign the iPhone.