iBike device advice

cycledogg said:

Hello,
I have been looking at the new iBike power meter device and would
like to know if anyone here has used it. I have read some reviews that
it is not very accurate but performs well for the money. Any commets
welcomed.
Cheers,
Rick in Tennessee

My comment is it relies on lots of assumptions to guess power. You
input your aero/wind resistance by doing various rollout tests. Your
aero/wind resistance varies a lot whether you have your hands on the
tops, hoods, or drops. So you pick something that approximates
roughly which position your hands are in most of the time. So you
know your power measure will be wrong when your hands are in other
positions. Seems kind of odd to know the numbers are wrong but still
think the device is worth having. I would guess there is something
similar with tire pressure. The iBike uses speed and incline and wind
direction to guess power. If you really under inflate your tires on a
ride compared to what you input for your rollout test, your speed will
be lower. Imagine riding on flat tires. Even though the power you
are applying is the same no matter how much pressure you have in your
tires. But the iBike will just look at speed and assume your power
output is low because you are not going very fast. Too many guesses
at power output to make me comfortable spending $350 on this thing.

If you want to measure power, measure it more directly. At the hub or
at the crank. Where the power is applied. SRM or Powertap or
Ergomo. More expensive but more useful because you are measuring what
you want to measure, power output directly. Not guesses based on lots
of other things.

cycledogg said:

I have been looking at the new iBike power meter device and would
like to know if anyone here has used it. I have read some reviews that
it is not very accurate but performs well for the money. Any commets
welcomed.

Well, since any comments are welcomed, I'll toss mine in. Although
I've never used the iBike, I have been examining data files collected
during rides where both an iBike and a Power Tap were installed.
Overall, the iBike has the potential to be quite consistent with the
PT (very, very close on uphills; close on the flat; often a little
flaky on downhills or when the road gets bumpy). However, the
performance of a power meter shouldn't only be judged under ideal
conditions, or even under "average" conditions--it should also be
judged on how it handles worst-case conditions. Here are two plots,
constructed form data taken on the same route but one week apart, each
of which compares an iBike to a Power Tap. The top panels are probably
the ones you'll want to focus on:
http://anonymous.coward.free.fr/wattage/cda/pt-ibike-good.png
http://anonymous.coward.free.fr/wattage/cda/pt-ibike-evil.png

Whether "it performs well for the money" depends both on how much you
value your money and on what purposes you want it to fulfill. For
example, effective use of a power meter for -->training<-- purposes
requires a relatively high level of consistency -- if you don't have
high consistency, you're probably not going to get much more benefit
from it than you would from a standard HRM.

cycledogg said:

Hello,
I have been looking at the newiBikepower meter device and would
like to know if anyone here has used it. I have read some reviews that
it is not very accurate but performs well for the money. Any commets
welcomed.

I have one. It has limitations, but I find it to generally work well.

You will find that some of the most vocal critics of the iBike are
those who have never used it.

There is an iBike specific discussion group here:
http://lists.topica.com/lists/iBikeProPowerMeter/read/

And here is a review that mirrors my experience:
http://www.dailypeloton.com/displayarticle.asp?pk=10751

Here's one that claims to be unbiased but focuses primarily on the
weaknesses of the device.
http://www.onlinebicyclereviews.com/

My own quick summary
The good:
Device generally works pretty well.
Not nearly as expensive as other powermeters.
Requires no special hardware (hubs, wheels bottom bracket, crank)
Excellent customer service/tech support.
Device saves ride data for speed, wind speed, gradient , elevation,
power at 1 or 5 second intervals.
Device is upgradable through firmware (Heart rate monitor function yet
to come)

The not so good:
Device can be affected by vibration (worst case scenaro is a
chipsealed road at speeds over 20-ish mph, epecailly going downhill)
Cold weather operation can be a problem (battery is too weak)
Bundled software has "barebones" functionality and a few glitches.

DR

DirtRoadie said:

You will find that some of the most vocal critics of the iBike are
those who have never used it.

Perhaps, but that's a knife that cuts both ways. One could also say
that some of its most vocal proponents are those who haven't used
anything else. For example, the dailypeleton.com reviewer had never
used another on-bike PM while the onlinebicyclereviews.com reviewer
had. The guy who sent me the iBike-PT data files thinks that the iBike
has uses but guiding training isn't one of them.

Quoted message said:

DirtRoadie said:

You will find that some of the most vocal critics of the iBike are
those who have never used it.

Perhaps, but that's a knife that cuts both ways. One could also say
that some of its most vocal proponents are those who haven't used
anything else. For example, the dailypeleton.com reviewer had never
used another on-bike PM while the onlinebicyclereviews.com reviewer
had. The guy who sent me the iBike-PT data files thinks that the iBike
has uses but guiding training isn't one of them.

A Seattle area racer was talking to me about one a few weeks back. He
tried to use one. Apparantly, battery life was pathetic on his unit.
45 minutes on a 'mild' day with new batteries. The maker was
unresponsive to the problem other than offering a discount on the
batteries.

So, add another vote against being useful for guiding training,
especially if you don't live in Texas.

Orin.

See http://nyvelocity.com/content.php?id=889 for a review.
--------------------
Alex