New, somewhat affordable, power meter

[davep]

The current RoadBikeRider.com has a review of some interesting things from Interbike, one of which is a power meter that costs $349 and weighs 58 grams. It measures power indirectly and so there are no large hubs, crank sets, etc. And its Mac compatible. The question, of course, is does it work? I've actually just bought a PowerTap, but haven't even installed it yet (waiting for a cassette). This looks like it fits the bill, but I don't know if I want to be a guinea pig.

http://www.ibikesports.com/aboutus.html

[Needs Help]

How does it measure wind speed when you are riding? What does the review say about it?

[Dr. Doofus]

think there's only one way this could work

enter combined bike/rider weight

computer measures speed, gradient, wind speed and then calculates est. watts using a set formula

the problem here is the set formula would assume an average drag coefficient -- so the +/- accuracy of the virtual power meter would be thrown off by the aerodynamics (or lack thereof) of one's position


buy the power tap instead

[BarryG]

snake oil

[davep]

It would have to measure wind angle and bike speed to calculate the true wind speed, unless it works with apparent wind. Also, it doesn't have cadence or heart rate. And based on other bike altimeters I've used I wonder how accurate that function is? I think I'll stick with the Power Tap, at least until more reports come in.

[Too Tall]

It is an accelerometer. There is no way to tell how useful the information will be however from what little info. the maker gives it is not giving me warm fuzzys. This gadget used inside my hotrod is a different matter and will give good data but for nominal hp applications???? Nah I don't tink soooo. I want to slap this bad boy on my bars and run side by side comp. with SRM

The other side of this story is that performance data may only need to be reasonably accurate and highly consistent to be useful for coaching / training.

[davep]

Too Tall,

I am assuming an accelerometer measures acceleration. If you are riding a steady speed, whether it is 10mph or 30mph, you are not accelrating. How can it then measure force (power)?

I sent the company and email with some questions. We'll see if I get a quick (or any) response.

[Chris]

Here is some information on it from the txbra website. Apparently the measurement is based on wind resistance, speed, barometric pressure, etc. It's over my head, but it seems feasible.

"Inventors from Dallas and Boston have created a 57 gram wattage measuring device. It'll be built in Dallas, using aerospace technology. It has NO MOVING PARTS.

If you want to take a look, go to www.ibikesports.com, or SMS message me at 214-616-9850 or call and talk directly with the owners. We're debuting this at InterBike, so you can make cheaper orders now, if you're interested.

Trackies, TT'ers and MTB'ers will absolutely love it. Roadies will soon be able to truly compare ride after ride, day after day. Setup takes 15 minutes!!!!

Though it only works outdoors, this thing is a viable alternative to the current generation of ergometers.

Watts per Kilogram ya'll...
-Richard"

[Needs Help]

Apparently the measurement is based on wind resistance, speed, barometric pressure, etc. It's over my head, but it seems feasible.
What about when you are going downhill?

[BarryG]

It's over my head, but it seems feasible.Isn't that an oxymoron?

[Dr. Doofus]

looks like a slughtly improved HAC-4


pretty useless, really

[Chris]

See, I told you it was over my head!

[weisan]

The other side of this story is that performance data may only need to be reasonably accurate and highly consistent to be useful for coaching / training.
Bingo!

[Cadence230]

looks like a slughtly improved HAC-4



Exactamundo! It's virtual.

[Too Tall]

Did the HAC4 incl. an accelerometer? So, it is not entirely "virtual".

[keno]

If it's only good for outdoor use, it's limiting if you have to train indoors in the winter. Power intervals would be out, as well as sustained workouts at a particular level.

Even outdoors, I wonder about repeatability, depending upon the factors involved.

$350 ain't chopped liver, and that was about the cost of the Polar power set up, which was not a virtual one. I don't know if they still market it. It didn't compare to the alternatives of PT and SRM.

keno