The birth of the brake power meter

SQUEEEEEAK!!! Skid.
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Squeeeeaaaaaaaak
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We’ve all ridden with that guy. Whether in a race or just having fun ride in the forest, we’ve all seen him. He’s the proverbial yo-yo of cycling; he brakes too much, and pedals too hard. He’s slow and he’s fast all at the same time. Try to make a pass and he speeds up, buzz his tyres and he won’t move out of the way.

My guess is that we’ve all been that guy at one time or another (though I’m sure our brakes didn’t squeak as much!). But whether it was yourself or one of your mates, in the situation above you were probably left wondering: how much quicker could we go without all that unnecessary braking?!?

It was exactly a situation like this in 2014 that led to the development of the brake power meter (BPM from here on out). It was a right-place-at-the-right-time situation, and despite not being unique in wondering about braking, I was in the position to dedicate 4 years of my life trying to understand what all this braking nonsense meant.

GETTING TO THE RIGHT PLACE

I’d spent a lot of years racing bikes- from 24-hour death marches and the Enduro World Series to road criteriums and some cyclocross. I knew what it took to be awesome at these types of events, and had figured out (over too many years) that I lacked some of whatever it was. But in the process of learning I wasn’t going to cut it as a bike racer, I learned a lot about science and saw some holes in the science of the MTB.

I made the big move from Small Town USA to the slightly bigger town of Palmerston North New Zealand, to take up a PhD position at Massey University. I knew I wanted to study MTB…but what about it?? It’s such a complex sport! My supervisors had spent some time quantifying vibrations and they had a great team put together, but I had no idea what I was doing.

LIGHTBULB MOMENT

In the process of collecting some data for another idea we had, I found myself racing my supervisor, Steve, for the win in the local club XC championships. It was a heated battle. We were both suffering and were neck-and-neck for the win!

Now how the heck could I keep up with Steve?? You should seriously see the guy’s calf muscles! He had been a pro roadie for many years and could put out 350W for an hour, no problem.

Was it just a ‘good’ day for me? For his 350W, I was lucky to be pushing 250W with my tongue dragging in the dirt. Sure, the track suited me with its many many many (some would say too many) corners and minimal climbing, but according to our power meters, there was no reason I should be riding with him!

At various points throughout the race, I could hear the hum and squeak of Steve’s brakes. Whether this was due to the bike hanging up for too long and collecting dust or was thanks to his kids playing ‘mechanic’, it didn’t really matter. But thanks to this built-in audio feedback, Steve was able to let both of us know when he was braking.

Being a cheeky racer myself, I started to pay attention to his braking patterns. I knew that if I could save 1/10th of a second on a series of corners, I might make up some of the deficit I’d lose on drag-race and road sections. I made a conscious effort to brake less than he did- after all, I was struggling to keep up! It seemed to be working- after each corner I could see him out of the saddle and on the gas hard, while I remained seated and continued spinning at the same pace I had been.

…so in other words, I was putting in fewer big efforts by maintaining my speed more efficiently.

Cycling sports are all about efficiency, and optimizing efficiency to go as fast as we can—this is why we train our energy systems, lube our chains, stare at our power meters, replace worn-out bearings and pump up our tires to a pressure that juuuuust right. But maybe we should be paying attention to other kinds of efficiencies—like how efficiently we can ride?

At the end of the race only one second separated Steve and I, with each of us racing to our strengths for that course. It wasn’t hard to figure out that I was able to ride with Steve because he was wasting some of his energy; the next day I gathered my supervisors and told them I wanted to measure braking.

We started working on the brake power meter that day.

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