AeroPod, PowerPod and Newton

Hello everyone.

I´ve been using iBike for well over a year. Recently moved on to Gen III - glad I did! Although my old iBike I was fairly accurate and consistent (tested it against other PMs in the past) I´m impressed with the overall improvement mostly in regards to stability: it´s been working flawlessly everywhere, and the power readings are impressive - even though I´m yet to do the cal rides and CDs! Also the wireless function is just perfect now.

I´ve now started using the iBike with an indoor trainer (Fluid²) and have a few beginner questions. Any help will be greatly appreciated!

1) To start, I would like to know which trainer profile should I upload from the list for the Fluid². I´ve found a few over there, but they´re all different - by a fair bit. At first I picked up the kurtkin profile, but found the power X speed profile pretty steep compared to the lowest one (1up I guess). Should I do any adjustsments to any existing profile?

2) Does the pressure on the tires or the "flywheel load against tire" of the trainer impacts power readings, or this is not a factor? I usually check this for consistency before every indoor session but now it seems to me even more important.

Any tips to help me picking up one that would suit me best I´d appreciate. I dunno what should I do to get my Gen III indoor power readings to compare to my outdoor numbers (once I do the cal rides and CDs and everything), but as expected I would like to have consistent readings so I can do my "trainer rides" as close as possible to my "road rides" in regards to power.

Any help will be greatly appreciated. Sorry if these topics have been discussed before elsewhere in this forum. I did a quick search and couldn´t find anything specific, though many helpfull topics and tips around! Great forum!

Thanks everyone and a super ´09 for you guys!

Alex

I have a 2007 Fluid2 and I don't think any of the curves match my particular unit. They seem to over report power by a significant amount, again, for my particular unit at least. I've done separate fitness tests both outdoors and indoors (using the 1up profile as it has the "flattest" curve) and confirmed that the 1up curve over reported by almost 30 watts for my average power at LT. I've since adjusted the "B" factor in the coefficients to try to get similar results between the trainer and outdoor rides. In my case, I changed the B factor from -1.48 to -2.95. The results have been good, not exact by any means but at least my average power between similar indoor and outdoor rides are now close, which is all I was looking for.

I have a Fluid^2 that I bought in late 2006/early 2007. I would agree with etuaz's characterization of the power curves. They all seem to overstate my power on the traininer. I'm using the 1up one myself. Honestly, I'm sticking with it. I have enough data using that power curve that I'm hesitant to change the curves (and then have to restate all of the old data I have). At some point someone will join the forum that has an iAero and a Fluid^2. Then we can get another data point. The wheel's pressure on the flywheel does have an impact. Keep that and your tire pressure consistent. To me, for indoor training, I'm looking for relative management. If the curve isn't perfect, the only thing I can't do is make a good comparision to outdoor data. But, honestly, that isn't my highest priority. What I'm looking for is an understanding of my fitness as I suffer through the seemingly endless winter.

Thanks greg and etuaz. I´ve made some tests and tried different B factors for 1up, and now it seems more precise. I´ve also ended up with -2.9 myself, it now seems closer to my outdoor power reports. Maybe that´s the number for the Fluid², mine´s also from around ´07. Anyway, all I´m looking for is some relative consistency as it seems to me more important than accuracy. My outdoor power readings are quite accurate and I´m taking from there to kinda calibrate it for indoor use.