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IB14: Brim Brothers Toes the Line with First Wearable Power Meter

Written by Zach Overholt
13 Comments
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If you haven’t noticed by now, with products from companies like 4iiii, Stages, Garmin, and more, power meters are currently in a race to affordability, usability, and compatibility. As far as we know, to this point power meters have always been mounted somehow to the bike. Whether it is the hub, the crank, the pedals, one way or another it’s mounted to the machine rather than the man.

Brim Brothers looks to change that with their Zone DPMX shoe based power meter. Sandwiching the force sensor between the cleat and the shoe, the Zone sets the control pod on top of the toe for a rider based solution to power. Clip in after the break for more…

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Currently limited to Speedplay Zero pedal systems, the Zone DPMX plate replaces the current base plate one Speedplay cleats. Considering we just saw the new cleats from Speedplay we double checked, and the Zone system is compatible with the new walkable cleats. The pods on the toes are USB rechargeable and easily twist off to charge in the provided cradle. Battery life is expected to be around 15 hours per charge.

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Key to the design is their piezo ceramic sensor that is thin enough to fit between the cleat and the shoe without increasing the stack height. Measuring over 100 times a second, the system basically measures the squeeze on the sensor from the force you are putting to the pedals. The Zone DPMX is a true right left power system with total power, power balance, and right and left power, with the two sides talking to each other much like the Garmin Vector system and are ANT+ compatible. Conceived, developed, and tested in Ireland, the system is fully waterproof. Accuracy is listed at +/- 2%. Calibration is extremely simple – just tap on the sensor 3 times once it is installed on the shoe. Everything else is dialed in automatically.

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Since the sensor is very sensitive to bending or improper torque, part of the install process involves a sticker that is placed on the sole and a tube of Sugru. Once the Sugru is applied you install the cleat and tighten it gently to compress the Sugru and form a perfect curvature for the sensor plate. Once it’s cured, you’re good to ride.

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The Kit includes everything needed to install, use, and recharge the system and will retail for $999. Brim Brothers will be shipping the Zone DPMX in October and pedal systems based around other popular pedals are in development.

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Coming in at 50g per side, the true weight addition is around 35g since the system replaces the 15g Speedplay base.

brimbrothers.com

 

 
Zach Overholt
5,722 articles

Zach Overholt is the Editor in Chief of Bikerumor. He has been writing about what’s new in the bicycle world for 12+ years. Prior to that, Zach spent many years in the back of a bicycle shop building and repairing nearly every type of bike, while figuring out how to (occasionally) ride them.

Based in Ohio, Zach is now slowly introducing a new generation to cycling and still trying to figure out how to fit the most rides into a busy schedule as a new dad.

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Joe
Joe
10 years ago

Mnn. Sugru all over my shoes. You ever try to remove that sh*t? Good luck.

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Peter
Peter
10 years ago

@Joe:

DC Rainmaker has a write up about these, including an installation walk-through. The Sugru won’t get on the shoe itself: there’s a sticker/template that gets put down first.

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bent
bent
10 years ago

it looks like your shoe would be tethered to the pedal by the sensor. what if you have to stop and put your foot on the ground? would you need to first reach down and unclip the sensor from your shoe? what if you forget?

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bent
bent
10 years ago

never mind, i see why i’m stupid.

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joby
joby
10 years ago

I’m very intrigued with this set up…I think it is a great solution, especially for those of us not wanting the SRM set up and co$t and tired of seeing our other wheel sets gather dust while using the power tap. Reasonably priced at a grand, so I hope it will have a positive effect on pricing for other systems as well.

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Hobbanero
Hobbanero
10 years ago

I wonder if their algorithm deals with power applied around the pedal circle. I can see how it can measure if you are pushing straight down, but that only happens twice per pedal stroke. It must have an accelerometer to figure out cadence, and should know where the foot is in the pedal circle.

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Andy
Andy
10 years ago

How does it measure power on the upstroke if it works by measuring the squeeze between the pedal and cleat.. Cause on the upstroke you’re essentially pulling away from the pedal not down onto it so there would be no ‘squeeze’

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Loki
Loki
10 years ago

@Andy, the research shows that there is very little time, if ever, that cyclists pull upwards on the pedal on the upstroke. Most of the time that one feels you’re pedaling in circles and pulling on the up, you’re really just lightening the amount of downward pressure, mostly gravity related. There’s still downward pressure. Mountain bikers are more likely to use a pull stroke (to get over an obstacle) but this is usually only for a couple of strokes and then it is too energy costly to continue. Ironically, some papers found that mountain bikers had smoother pedal strokes on average than road bikers!

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PowerCrank User
PowerCrank User
10 years ago

@Loki, site your sources. I don’t buy your claims about not pulling up. Go for a ride on powercranks without pulling…

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kurti_sc
kurti_sc
10 years ago

dang. had me interested until i saw the price of a grand. I know this stuff is expensive and it costs money to develop. I just figured from the intro, that this was going to be much more affordable.
In all, it looks like a great product.
I have seen wear on that cleat adapter surface from my speedplay pedal. Will the piezo device see that same wear? that might be a longevity issue.

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feldy
feldy
10 years ago

If it only measures squeezing between the sole of your shoe and the cleat, then it would not only not give results for pulling up, but also not for pulling back or even a toes-down pedaling style (not that that’s necessarily desirable). However, I don’t see why there couldn’t be x-y-z oriented piezos to get the pull in any direction (well, sideways probably isn’t all that helpful). Furthermore, even though the article says “squeeze,” I don’t see why it couldn’t measure elongation on a pull in addition to contraction in a push.

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Psi Squared
Psi Squared
10 years ago

According to DCRainmaker’s description of the installation process, the system is calibrated via tapping after the cleat is entirely assembled. Theoretically, it should be able to read any reduction in compression as the result of pulling up on the pedals so long as their system can read the polarity change in the electric signal coming out of the piezos. Of course as someone else mentioned, pulling up is a rare thing in real life cycling.

The DCRainmaker article also talks about an issue that Brim is having with shear forces influencing their signal.

I’d recommend that everyone read the DCRainmaker article. It’s more complete, even though it is based on a single ride on a still developing system: http://www.dcrainmaker.com/2014/09/brothers-announces-production.html

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Psi Squared
Psi Squared
10 years ago

Reading a decrease in compression, however, would require quantifying the cleat screw response to strain as a reduction in compression of the piezos would require a reduction in strain of the cleat screws. Given that, it’s unlikely the system can read a reduction in compression and interpret it correctly.

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