iBike doesn't measure power, it calculates it. There has been some debate over this device for a while, some googling should give you more info.

You can find a wired powertap setup relatively cheap nowadays. I'd go for that.

Which one are you getting? You can a get a used wired powertap for 400-600, which is the price of a ibike. I had a ibike and tested it against a powertap. It was within 5% which could be alot. The difference is one calculates power, where the other measures it. You can rent a powertap, something to think about. A ibike wouldnt be bad for a road bike, but for a tri bike it really dirties the air. Having owned both a ibike and powertap I can say a powertap is less hassle and easier to use. If you get the wireless ibike then upgrade to a powertap or quarq. Here is the ibike paper comparing powermeters. http://www.ibikesports.com/...on_ride_analysis.pdf

Good luck.

those Ibikes really blow. I dont think they work on a trainer either...

So, then I guess I have a follow up question. I don't want to race with a Powertap, so can it still be used as a regular computer without the Powertap wheel (like with non-Powertap race wheels?).

If you have the wireless version you can get a seperate speed/cadance. It depends on how much you spend and what options you use. For racing I use a disc cover. So for 600 I have a pt and race wheel. Other options are getting a wireless hub with garmin head unit. The elite+ and garmin 310 seems to be a popular build right now. Do you do short or long coarse racing? For long coarse I would use the powermeter in the race with short coarse its nice to look at the data afterwards.

I do sprints and olympics almost exclusively, with a 70.3 thrown in about every 2 years. I have a set of Fulcrum Racing 7 training wheels and Flashpoint 80 race wheels, and I would get the Powertap built in to the Fulcrums. I don't want to fool with power during racing, but would like it for training. I need to stay in the $600 range, so I guess my only option would be iBike or Powertap Comp Wired. I just don't want to have to have separate computers when I take the Powertap off for racing.

powertap comp + wheel cover, better than your rear fp 80

IMO, training with power but not racing with it is foolish and indicates you are missing the point. If money is a factor, the cheapest as well as fastest solution for you would be to sell your rear FP, get a wired PT and a wheel cover. That will be much cheaper than keeping your current wheels and getting an ibike. Replacing your rear FP with a covered wheel will be faster as well.

That being said, if you put a magnet on a regular wheel with the wired PT setup so that it comes near the fin, and change your head unit to cycle computer mode, it will read speed/hr still.

I agree with the rest. I sold my 404s to get a pt. Now with a rear cover and a deep front I do not see a differnce. You could race with a garmin 305 if you want other choices.

check out jackmotts links, wheel cover is goiing to be faster.

there...fixed the title.

Unless of course you are using it paired with something ANT+.

:)

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36 kona qualifiers 2006-'23 - 3 Kona Podiums - 4 OA IM AG wins - 5 IM AG wins - 18 70.3 AG wins
I ka nana no a 'ike -- by observing, one learns | Kulia i ka nu'u -- strive for excellence
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Triguy,

I just order an iBike based on my LBS's recommendation (below). I have a Garmin 405 watch so I purchased the iBike Sport GT. The new GT has +Ant capabilities making it a better buy if you have a Garmin than the iPro or iAero. I hesitated to purchase the iBike because of negative comments in this forum but in reading the comments I had trouble distinguishing what people thought they knew from what they actually knew. I didn't find anyone that said that they had one and got rid of it so I went with my LBS's recommendation.

LBS's email "last year a day or two before the pro race, a rep from iBike came to the shop to present their products to me. we had a long discussion in which i went at him pretty being critical about the seeming lack of technology & accuracy (based on my ignorant assumptions) & he addressed each & every concern. (eg) what if i want to train on my rollers or stationary trainer, how can the device work? i learned that they have gotten calibrations from many of the companies who produce those products & that they provide the relevant power data. additionally, he showed me graphic evidence in which one of the pro teams they sponsor had done training rides w/ the iBike AND a powertap hub as well as the iBike AND an srm power meter simultaneously on the bikes. the resulting power data provided was nearly identical. so...i became a believer in their product. i presented the information to one of our shop owners, & he agreed that when he'd seen the product at the super show in las vegas, he had been highly interested. so, we went ahead & brought their product in. so far, we sold a few & everyone has been pleased with them. the portability of their power meter, not being married to a specific wheel, the accuracy of their reading, & the price, make their power meters a GREAT purchase in my opinion. they sell 3 levels of their power meter & the top two, the iPro & the iAero have downloadable capabilities. i would gon to their website, check out the features you want to have & then come see us about moving forward with one. training with power is ABSOLUTELY the BEST way to train as a cyclist & provides you w/ the best bang for your buck to that end."

Thanks for the info. Did they mention if aerobars or drafting affect the readings? That's the only real concern that I have.

No, I didn't think to ask. I just ordered it this week so I don't have any experience with it yet.

I had a Iaero and got rid of it FWIW. In the end its going to depend on what you want or makes it happy.

I have the GT edition that I use on my road bike and it did pick up all of my ANT+ devices. So far it has been extremely flakey as far as accuracy goes. I have tried calibrating it 2x with similar results. I am going to give it another go before I really start bitching though. I don't see how it could possibly work well on a TT bike since it relies heavily on wind speed and if you mount it on the stem the aerobars and the bottle will pretty much block all the wind or even worse, create vortexes that will seriously mess it's logic. iBike does sell a TT bike adapter which looks like a piece of medicinal tubing that acts as an air intake and can be moved out of the way. I decided to hold off on that until I am actually happy with the device I already have.

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Velosurance - bicycle insurance

just talking to a lady friend of mine who uses I bike, definatly a POS, just get the wired PT and you will be fine, seriously, dont waste your money.

A buddy of mine has an iBike. They suck and he was duped into buying one by some dbag at his LBS. Now, he wants to ditch the iBike and get a PTap. Wired PTaps are pretty inexpensive and just as reliable and helpful as a wireless PTap SL or ANT+ CPU. Save up your money until you can do it right and get a PTap.

jesus christ, your lbs is retarded.

While that's technically correct, I think it's also parsing words a little--and it implies a level of parity between strain gauge-based PM's and the I-Bike which simply isn't there. The strain gauge-based PM's measure force and velocity and calculate power (and yes, you could also make they argument that they don't actually measure force but measure impedance and calculate force--but at this point we've made the word 'measure' pretty much useless...). The I bike makes direct measurements of wind speed, but it also relies on assumptions for Crr and CdA even it these are 'measured' during the calibration ride, and assumes that these are fixed values--even though under most circumstances they simply aren't.

Technical mumbo jumbo aside, I used an Ibike for about 2 weeks, in conjunction with a Powertap and an SRM. My conclusion is that it's a neat gizmo, but it doesn't measure power accurately enough to be of any use in my training. My other conclusion is that life is WAY to short to deal with the setup of the unit.

"jesus christ, your lbs is retarded."

That's like saying a car salesman is retarded for selling the extra rust protection.

The more popular powermeters calculate power from estimates of torque and rotation rate (cadence or wheel speed). Rotation rate is pretty easy to measure. While a bit more tricky, torque can be reliably measured through the use of strain gauges.

So there are only two items to measure.

The iBike, by contrast, measures 1) windspeed, 2) slope, and 3) acceleration. These three items are all more difficult to measure than torque and rotation rate.

The iBike also uses estimated coefficients for aerodynamic drag and rolling resistance, and assumes that these are constant throughout your ride. Where I live that is not a good assumption.

The net result, as I know from personal experience over three years, is that the iBike does not measure power reliably.
For example, if I ride my P3 and calibrate the iBike on smooth pavement and in the aero position, the power numbers will be off by 30W or more (as compared to my Powertap) if I get out of the saddle on chipseal.

In addition the iBike is tedious to set up before each and every ride, and eats batteries like I would like to eat potato chips. I greatly prefer my Powertap - I get on the bike and go.

Don't get me wrong - I like my iBike. It is a cool gadget and I still use it occasionally (mostly to get course profiles). But it is not a powermeter and I would not use it for training.

I strongly recommend not getting the ibike. I purchase the ibike aero and had so many problems including inaccuracy and contact lock up. On most rides, I had to take out the battery 3 to 4 times and reset the unit. I read a post a while back which stated that the accuracy data when ibike compared its data to the SRM and was altered after the fact. this is why the info posted on their website show similar power info between all units. I personally tested an ibike with an srm, power tap and quarq. The ibike data was awful. In my opinion the srm is the most accurate with the quarq and power tap tied right behind it. I suggest the quarq because of cost and not having to have two power taps, one for training and one for a disc wheel.

Also, do not believe anything you read on their forum. I had tons of posts where I stated all my issues. Some how most of my posts were deleted. The owner of the company claimed he deleted my posts because he was deleted all posts which dealt with older software versions.

I had so many issues, that the owner returned my money and let me keep the unit. I still had so many issues and they were interfering with my IM training that I returned the unit to the owner. I purchaseD a quarq and am extremely happy with it. I recommend the quarq. It is simile to use and very accurate.

I live very close to the ibike headquarters and spent, many days with the owner trying to fix the issues. I do have to say, their customer service is superb. I know many local south Florida triathlets and road racers who used the ibike and have given up on it.

I know the other power meters are more expensive but in my opinion, they are worth it. The ibike is one of the biggest pieces of junk I have bought and used. [

Oh my.