Thursday, August 04, 2016

Data Nerd

Every part you can buy for your bike comes with some sort of promise. Makes you more visible! Makes you faster! Sleeker! Reduces weight! Increases virility!

Obviously a lot of it is marketing, and sorting through it without significant financial outlay is challenging. We have do-gooders in the community, like DC RainMaker, who review products like crazy to separate the wheat from the chaff, but there's just so much stuff out there, and so much anecdotal evidence, that even with expert reviews it's hard not to spend money on a promise.

I've spent a lot of time, money, effort, and research making my racing bike as fast as it can be. Fully equipped, it comes in under 17lbs and is dripping with just-shy-of-top-end equipment. Carbon everything, ceramic bearings, and data sensors out the wazoo: power, speed, cadence, GPS.

I haven't, however, spent a bunch of time or money making my commuter bike faster. It has an aluminum frame, disc brakes, exposed cabling, fenders, and a rack. I did spend money on a decent set of wheels, but only decent--no carbon here. The commuter sports a mostly-Shimano 105 drivetrain, with stock chain and rings. All compact, unlike the race-bike's 53/39 x 11/25 big boy setup. And about half of the miles I've put on the bike have come with panniers, a tool bottle, and usually a big honkin' light with an external battery.

Point is, this bike ain't light. Commuter weight, with laptop and everything else, comes in right around 40lbs. And yet, in spite of all the FASTER! LIGHTER! SEXIER! parts on the 17lb bike, I ride them just about the same speed. Most of my rides average just over 20mph over their length.

So if I can ride two wildly different bikes at the same speed, was all of that money a waste? Could my commuter be an effective racer? That question has bugged me a lot, recently. I've even considered racing it at Bryan Park just to see how it would do. And actually my first ever race was on the commuter: the failed Monster Cross back in February. I slapped some CX tires and SPD pedals on it and rode it until I couldn't any more (and wrecked it twice).

One thing that was holding me back from trying the commuter in a race, though, was a recent spate of flat tires. The decent wheels I bought back in the winter were Mavic Ksyrium Elite Disc 2015 wheels. The were on clearance, and came in at 1540g for the whole set, which kinda blew me away for non-carbon. They're weird looking, but you can't beat the value, and I have some nasty hills to climb on my commute. They also came with extremely proprietary tires, which I didn't realize had zero puncture protection.

I got so tired of replacing tubes that I swapped one of the Fuji's stock Vittoria Zaffiro 700x28 tires on the back. Worst case, I figured, I was training and it would help make me faster on the race bike. Best case, I wouldn't really notice a difference.

I think it went somewhere in the middle. I certainly knew the tire was heavier, but as many components as I've hung from the scales, I'd never actually weighed one of these bricks. For the past 2 months, I've had a 385g tire hanging off the back of the bike, but hey: no flats.

In June I gashed one of the race bike's tires and switched over to the new hotness: Continental Grand Prix 4000s II. They were 10g heavier than the previous tires, but advertised LOWER ROLLING RESISTANCE! and INCREASED CORNERING GRIP! and FASTER! SEXIER! STRONGER! And I have to admit, the bike felt faster. And instead of wiping out in the rain at Page Valley, they cornered pretty well.

I figured it might be worth a shot to get off the commuter's brick tire and standardize.

This morning I got up early and mounted a 25mm version of the same tire on the commuter. It weighs 225g, a full 160g less than the Vittoria, and all of that savings comes--not just in rotating weight--but at the outermost point of rotating mass.

And the ride in was amazing. I tore up hills at 25mph. I raced a Honda Ruckus. I felt fast. But more importantly, I felt like the bike wasn't sapping my strength with every effort. So at 20 miles, I felt as good as I had at 5 miles. And it got me wondering if those marketing claims are real.

To the data!

I track my rides through Garmin Connect and Strava, my sleep and weight through Garmin Connect, and my food through MyFitnessPal. Looking back over every commute with the bike in its current configuration, I was able to determine which days I'd packed my lunches, which days I'd slept better, and capped it off with Strava's Fitness/Freshness/Form scores (from the previous day) to see what my overall performance level should have been for a given day. For the wind, know that most of my ride is due south. Data like estimated average power was ignored as subjective, and morning humidity in my region is just shy of jungle.

Bearing in mind that I've only put one ride on this tire so far, and the fact that this bike lacks a power meter, and some days I might have packed a change of clothes, etc, it's fascinating to see that today was my fastest moving ride by over a minute, with a lower average heart rate.

The temperature was lower, and my average cadence was higher, but my weight was not at its lowest, I barely slept last night, and overall time shows that I stopped for a number of red lights, which means some of that moving time was spent stopping and starting.

Because I'm always running late, I only ever ride hard, but this morning was the first time I've ridden hard and felt like I could just keep on doing it, in spite of form, sleep, whatever else was in the way. And the numbers support it: my heart didn't have to work as hard to fuel the effort.

I credit the tire. So there you go, kids: in my completely academic test that failed just about every scientific standard, I think I've effectively demonstrated that pulling 160g off the rotating mass of the bike and reducing the rolling resistance has made me FASTER (0.6mph average over my previous best, or 1.3mph better than the average average)! STRONGER (lower heart rate)! LIGHTER (-160g)! The Continental marketing department can rest easy tonight.

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