Metrigear pedal spindle-based weenie-compatible power meter

[djconnel]

Nice review here.

[tranzformer]

I so can't wait for 2010 and the new power meters and ANT+ units coming out. It will be a great year for us. Too bad not so much for my savings account.

[gregclimbs]

There is a lot of misunderstanding about exactly how these pedals work...

I wrote up part of our conversation from interbike here:

http://wattagetraining.com/?p=505

I hope that helps make it clearer...

G

p.s. Sorry for linking away, but with the pics and text...easier to link to my post than redo it all here.

[djconnel]

Cool: Piezoresistors are potentially substantially lower power than traditional strain gauges.

I want to do a write-up on the 12 pedal degrees of freedom and how the Vector promises to provide useful information on 8 of them....

Degrees of freedom: average and difference for each of the following: displacement along x, displecement along y, displacment along z, rotation about x, rotation about y, rotation about z. Two of the three rotation axes are free on Speedplays.

But with Look Keo, not the case. So they can't ignore rotation about z (the axis perpendicular to the pedal surface).

[tranzformer]

Greg, seems like you had the chacne to talk to the Metrigear guys a bit. Without revealing any sensitive info, how close do you think they are to Q1 2010 release? Is that very realistic from your talking with them? I might even be willing to wait for them to release the Look Keo version if they got to that a few months after the Speedplay's.

[djconnel]

What I'd say is: what did you not see at Interbike? What you didn't see was a stationary bike set up with these pedals reporting power to an ANT+ Sport head unit. Since that wasn't ready, Q1 is obviously a no-glitch forecast, and how often does the no-glitch scenario play out? Lightning was also forecasting Q1 when they revealed their cranks at Interbike 2007, and they weren't available until 2009, a year later. Quarq was also considerably delayed from early forecasts. So there's big error bars on Q1 in my mind.

For the Look Keo: I don't have one for reference. What you need is a hollow accessible from the end that is not needed for a hex wrench to be inserted for installation or removal. For example, the Speedplay Nanogram has the accessible hollow but it lacks a wrench flat and so inserting the Vector hardware would make installing or removing a challenge.... If the Look meets this condition, then it seems to me it should be as quick as a month or so to dial it in, assuming adequate human bandwidth. An issue with the Look is a lack of rotational float means additional moments are applied to the pedal, so I don't know if this would complicate things.

[gregclimbs]

I updated the post with some info that I forgot to include about gauge factors and with some feedback from the Metrigear folks about direction for next pedals.

As the the question of will they hit their target.

I really don't know. I understand that they have actually been working on these for almost 5 years.

From our observations, the pedals appeared to be sending over ant+ in the demos. Althought the demo pedals were clearly using development boards since they were larger than the shown molds for the crank pods.

Now, that could be because the production boards were in production or it could be because those boards they had tested and knew worked and wanted to make sure there wasn't a failure in front of everyone.

Or it could be because the production boards aren't designed.

I suspect that a group as smart as this, who have been working for 5 years on an idea have had their share of setbacks and failures. I also suspect that they are pretty good by now at determining THEIR timelines. I suspect that they will be on time.

Now, as to when a Keo comes out the door... that is a big ?

g

[djconnel]

They are very bright. So are Jim@Quarq and Tim@Lightning. Yet neither of these guys were able to make the target at product announcement. It's the way things go.... The only thing you can anticipate about unanticipated problems is that there will be unanticipated problems.

Here's the look... only issue is a mechanic might be tempted to jam a wrench into the end, which would be bad if it's stuffed with electronics . Actually it looks like there's a cavity well beyond the range of the hex recess, so other than the issue of connecting an external battery, it appears secure.

[youngs_modulus]

Hey Dan,

I know you have Lightning carbon cranks. I'm thinking about buying a set--this is in anticipation of picking up either a Quarq Saturn or Metrigear pedals. Looking at the Metrigear appendage (the part that bolts to the pedal from the inside face of the crank--probably the ANT+ transceiver), it seems like that part may not fit all cranks. Do you happen to know whether the appendage will fit Lightning cranks?

Maybe Metrigear will offer an array of appendages (or maybe just spacers) to match different cranks. A sloppy fit at the appendage/crank interface would look ugly, but I'm more concerned about the Lightning crankarm being too "tall" (too thick in the fore/aft direction if the cranks are at 12:00 and 6:00) to fit the Metrigear appendage.

Thanks,

Jason

[djconnel]

Good question! The battery/antenna on display at Interbike was a prototype (mounted on a Fulcrum crank), not a finalized product, so I don't think it's a sure thing yet if a particular crank unit will have issues. My guess is no problem. But this is a question Metrigear would need to answer.

[gregclimbs]

Looking at the Metrigear appendage (the part that bolts to the pedal from the inside face of the crank--probably the ANT+ transceiver), it seems like that part may not fit all cranks.

Go back and look at the pics of the way that it mounts here:

http://www.metrigear.com/products/

The dogbone is LONG to allow the sensor to mate flush against any crank. The clocking of the dogbone doesn't matter to the unit.

g

[TiBikeNut]

I had given up on getting a power meter but at less than a $1K (including pedals), sign me up!

I am not too concerned about accuracy relative to other devices - especially if they differ only by a few %s.

All I want is the device to be consistent versus itself.

Does anyone know if 405HR watch would work to store the data from this power meter? Thanks

-George

[djconnel]

It won't. See specs here.

While the watch is ANT+ enabled, the key question is whether it pays any attention to power data. The specs say it does not.

The 310XP should work, however, according to its specs (at least for total power, not for L-R balance or other pedal stroke metrics).

[TiBikeNut]

It won't. See specs here.

While the watch is ANT+ enabled, the key question is whether it pays any attention to power data. The specs say it does not.

The 310XP should work, however, according to its specs (at least for total power, not for L-R balance or other pedal stroke metrics).

Thanks for the info.

So what is the cheapest ANT+ compatible display?

-George

[djconnel]

Probably the Garmin Edge 500.