fa63

I will post an iBike data file on here for you all to look at when I am able to download the data; however, I imagine it would look similar to what you posted.

And I don't see why you couldn't train with the iBike for efforts at and above V02 max, but that is OK; I am glad you are happy with what you are using.

Homebrew01

Because MUPs are not meant for high speed riding due to the mixed population of users: unpredictable kids, dog walkers, skaters ...

fa63

I guess I should have clarified; this one has a 2-mile long access path that leads to a 7-mile loop with a wide asphalt paved road. I do my riding once I get in the loop where there are essentially no kids or dog walkers. Everyone else does a good job staying to the right. Plus there is hardly anyone in the loop at 7:00 AM when I start riding.

But thanks for the concerns.

teetopkram

I train M-F on the 7 mile loop fa63 is referring to...while the early mornings and after work hours get a little crowded, throughout the middle of the day its quite deserted. Weekends are another story altogether. Its a wide paved path through the water wellfields. There's a 2 mile long access path to get to the 7 mile loop that IS usually more filled with children on bikes, walkers, etc. I typically use that as part of warm-up...however, once you get on the 7 mile loop its mainly cyclists, rollerbladers, and runners (the families turn around to go back to the parking lot and the runners often stick to the ground/grass rather than the asphalt). I'll do a 20 minute test in the middle of the day without seeing anything except snakes, deer, gopher tortuous, buzzards, and an occasional bobcat.

We are EXTREMELY lucky to have this area near us...riding on the roads around here is taking your life into your own hands.

Bob Dopolina 

Pul-lease.

Getting you gum from a gumball machine relies on physics too but that doesn't make a gumball machine a power meter.

Strain gauges generate actual, repeatable hard data based on their quantifiable physical properties. The iBike doesn't. Hardly the same thing.

The OP did make a good point about being consistent. If the iBike generates consistent numbers for you under most conditions then it may be of some use. Those number will not be comparable to the numbers generated by other riders using more accurate systems, however.

If this suits your needs then it may be a viable option for you.

For me, I'll stick with the PM I have at the moment.

merlinextraligh

To me the problem with the Ibike stuff is the value proposition, i.e. price. The Ibike Sport is $249, but not dowenlaodable and jumps to $399 for wireless.

For me, and I would guess most people training with a Power meter, you really want to be able to download your data. So you have to go to the Ibike Pro, and now we're talking $459 to $599 which is way to close to a Powertap.

I've contemplated getting the Ibike Aero, (for the virtual wind tunnel with a strain based power meter, and to use on the tandem) but every time I choke on the price.

aggro_jo

You should ride next to him so that you can glance over at his iBike and see what kind of power you're putting out.

StefanG

Correction - "estimated power"

rruff

Cute. All PMs rely on instruments and physics to translate measured quantities into power. The only issue with the iBike (or any of the others) is how accurate it is at determining those quantities, and how much the inaccuracies effect the power number. The iBike needs to determine slope and windspeed with great accuracy, and this is very difficult. Small errors in slope and windspeed can become large power errors... especially if you are going fast. If slope and windspeed could be determined with great accuracy, then the iBike would be a fine PM.

Brian Ratliff

If wishes were fishes....

Details matter. A strain gauge is subject to far less measurement uncertainty than the measurements the iBike makes.

Homebrew01

To me, the ibike vs pm seems like the equvalent of telling the temperature by:

A) Using a thermometer (power meter) or
B) Putting a glass of water outside, very carefully measuring the rate of evaporation over a fixed time, based on wind speed, relative humidity, amount of sunlight, starting temp of the water ....
too much can go wrong too easily ... should we stop now ?

jrennie

By rruff's review it seems the only time the ibike doesn't seem to work very well is in windy, cross winds, drafting, fast, downhill or rough roads. Sheesh it sounds like a deal cause I never have any of those conditions on a daily ride, even better as I never experience any drafting or going fast in a race.

rruff

Isn't that what I said?

rruff

Isn't that what I said?

kleinboogie

I figured you would.

Brian Ratliff

@rruff
I have no idea, but I guess it was worth repeating... You seem to be hedging around the subject of accuracy by introducing a lot of wishful thinking.

rruff

Not at all. I'm just pointing out that the concept is not inherently flawed, and that it is possible (at least theoretically) to build an accurate PM that works like the iBike. You just need to do a very good job of measuring slope and airspeed accurately.

fa63

I find it interesting that this point keeps being brought up (and I am assuming you and others that make this statement haven't used an iBike before). What do you guys think about the evidence out there, some even from credible sources like VeloNews, that suggests the numbers between the iBike and the other systems are very close? Maybe the unit really does a decent job of measuring wind speed and gradient in most conditions, and the assumptions in rolling and aerodynamic resistance are pretty good as well?

Racer Ex 

Just because a magazine says something, doesn't make it true. Trust me, I used to edit one and have written for many.

The iBike is better than nothing. It's not in the same conversation as strain gauge based units or even the (may god have mercy on it's soul) Ergomo. It's wholly inaccurate under a fairly wide set of circumstances. It's accurate under others. IF the speedometer on your car operated like this you'd get a lot of tickets.

Out-The-Back

To me, it wouldn't be so much about accuracy but consistency. If it's your only source of information and you derived your FTP with it and trained as such with it, as long as it's consistent, it makes no difference if it's accurate compared to whatever set of standards you want to compare it against. However the fact that it's ability to give consistent results is questionable, compromises it's ability to do the job for which it's designed. Therefore rendering it virtually useless. Second of all, it's ability to give immediate feedback also compromises it's usefulness. When doing tempo stuff and longer rides, you can effectively use HR, it's the intervals and such that the PM is really useful where HR is delayed and apparently so is the iBike.

fa63

Of course, but does that mean that there isn't any truth to what they reported? Here is the link, I will everyone make up their own mind:

Link

Here is the link to an article Florida Racing Magazine published:

Link

Once again, I just wanted to share my experiences; hopefully it will help someone one way or the other. I obviously like the unit, but not having used a strain-gage based PM, maybe my expectations/standards are low for what a PM should do...

Racer Ex 

Well, this is true and really an unintentional slam of the unit:

"But since roll-down tests are done in your standard riding position these fixed numbers produce accurate results most of the time"

Lay folks would be pretty shocked at what seemingly subtle changes in position can produce in CdA; pencil that out to watts and you'd realize what a big +/- reality you end up with.

RChung

Looking at averages and saying "they're very close most of the time" is less important than knowing the specific conditions under which they're not. Ron is way more credible about that than a review you read in Velonews -- and, as an aside, I'm not sure I'd be pointing out a review by the salesman who sells ad space for a cycling magazine. Just sayin'.

[Edit:] BTW, I don't have a dog in this fight. If you like your iBike Sport, that's fine by me. For many people something like the iBike Sport is a gateway drug and it sounds like you're interested in moving up to the hard stuff. Maybe Velocomp should make the first one free.

rruff

IMO that is more of a feature than a bug... because physiological stress also varies with position. Calibrate it for your "fast" riding position and it will automatically penalize your watts a little when you are less aero.

If that was the only source of error, I wouldn't be bothered at all.

I've had one for almost 3 years now... paid ~$325 for wired unit on sale, then upgraded to the newest generation when it came out. I use it to track my AP and get a TSS and TSB (NP is usually too high, so I have to guess on that). Many of the roads around here are rough enough to effect the slope determination, plus the wind and hilly terrain make it a very challenging environment. +-200W errors on a fast descent are common. I don't worry about the numbers til I get home, when I'm usually able to correct the data pretty well.

It's a very nice bike computer... but limited as a PM.

fordfasterr

Bad assumption. Not true at all. I've been using the iBike Sport since 2009 and it works fine to this day.

The delay you mention is just fractions of a second.


... Heart Rate... lol


I collect the data using the Garmin 500 that I need anyway and download and analyze the power data just like any other power meter.

Another great benefit to this thing is that I don't have to use a heavy wheel or ever change batteries in the hub unit (like the PT), and I can swap it around to my TT, Track, or various road /training bikes without any hassle.