Brim Brothers Power meter.

[Gman1834]

Interesting read on power meters.

http://www.brimbrothers.com/2011/02/cleats-and-pedals/

 

Let’s get down to some details of how our power meter will work with your cleats and pedals. We’ll start with a little introduction to how the whole thing goes together, and then we can take a look at how this gives you a whole load of flexibility.

 

 

Two pieces

Our power meter is made up of two main pieces: the pod on top of the shoe and the sensor unit inside the cleat. The pod contains the electronics, and the sensor unit contains the miniature force sensors. The pod and the sensor unit are connected by a tiny cable down the outside of the shoe. You can remove the pod for charging and configuration (we’ve got a really nice arrangement for all that), leaving the cable and sensors still in place. The sensor unit is clamped into the back of the cleat when you bolt the cleat to the shoe, so the sensor unit is protected and will not suffer damage when you walk or when your shoes get knocked around.

 

 

Special cleats

The power meter works with normal pedals, but it needs special versions of the cleats. Our initial launch of the power meter will be for Speedplay Zero pedals and cleats, with versions for other popular pedals and cleats to follow. Speedplay Zero cleats have three separate parts but it’s only the black base plate of the cleat that is different for the Brim Brothers power meter. The special base plate has a space in the back of it for the sensor unit. You just clip the sensor unit into the space in the base plate and then bolt the base plate to your shoe as normal (and then attach the rest of the Speedplay cleat). Other types of cleat will work in a similar way, with a space in the back of the cleat for the sensor unit.

 

 

Replacing cleats

The sensor units can be moved from your old cleats to your new cleats. When you need to replace your cleats you just remove them from your shoes, unclip the sensor units from the back and clip them into the new cleats, and then bolt the new cleats to your shoes as usual. You’ll only need a new sensor unit if you change your type of cleat (sensor units vary slightly for different types of cleat), but the same pod will work with any sensor unit.

 

 

Calibration

After you install a sensor unit and bolt the cleat onto your shoe there are some very simple calibration steps that need to be done. The calibration is not affected by how tight the cleat bolts are (within reason!) because the piezoceramic force sensors automatically zero themselves, but there is a need to calibrate for slight variations in the position of the cleat and the sensor unit on your shoe. The calibration information for a sensor unit is stored in that sensor unit, so any pod connected to it will know the calibration automatically. I’ll talk more about calibration in a future post.

 

 

Multiple shoes

If you happen to have more than one pair of cycling shoes you can easily move your Brim Brothers power meter between them. Just fit sensor units to the cleats on each pair of shoes, and then move your power meter pods onto whichever pair of shoes you will be wearing today. The pods will automatically recognise which sensor unit they are connected to and will use the appropriate calibration information, so there is no need to recalibrate each time you move pods between shoes. This is true even if your shoes use different types of cleat, so if you have bikes that use different types of pedals you’ll still be able to use your Brim Brothers power meter on all of them (if they are all supported by Brim Brothers).

 

So there you have it, a quick tour of how it will work with your cleats. In my next post, in a week or two, I’ll take a brief look at the benefits and drawbacks of the various techniques used by different power meters as impartially as I can (given my built in bias!). Now back to work.

 

 

 

 

 

http://www.brimbrothers.com/wp-content/uploads/2011/02/pod1.jpg The production version has a much slicker connection system than this prototype.

 

http://www.brimbrothers.com/wp-content/uploads/2011/02/speedplaybase2.jpg The sensor unit goes into the cleat.

 

http://www.brimbrothers.com/wp-content/uploads/2011/02/fourcleats.jpg We’re planning on versions for different makes of cleat…

 

http://www.brimbrothers.com/wp-content/uploads/2011/02/threepedals.jpg …and different types of pedal.

 

http://www.brimbrothers.com/wp-content/uploads/2011/02/speedplaycleat2.jpg The first version will be for Speedplay Zero cleats.

 

http://www.brimbrothers.com/wp-content/uploads/2011/02/speedplaycleat1.jpg The sensor goes in the base plate of the Zero cleats.