April 21, 2015

Tuesday Rant: Down With the Metric System!

Seriously, weight weenies, listen up. I was once one of you. Your brains are being tricked by the evil metric system.

You weigh something like 80,000 grams, plus or minus 20,000 or so. If you’re really big or really small you might be outside that range, but you’re probably not.

If you have a nice, light (mountain) bike, it weighs something like 10,000 grams.

To make the math easy, let’s say that when you’ve got a couple water bottles, clothes, and some tools, you and your bike are 100,000 grams.

If you know what these are, you have a problem

So a crazy light, say, stem, that saves you 50 grams, is 5/10,000 of your total vehicle weight. That’s 1/20 of 1%. To even hit a 1% savings, you need 1000g of lighter parts/frame. You can certainly pull that off, but it’ll cost you multiple thousands of dollars to do in most cases.

Worst of all, it won’t actually make you 1% faster, since there are lots of things that aren’t affected much by weight at all (air resistance, drivetrain losses, etc).

And yet, weight weenies, you spend countless hours weighing parts (and your bikes). You obsess over the weight of everything and the first thing you do when you see a nice bike is pick it up to see how light it feels.

Yet mostly, you’ve never really spent time testing, say, tires back to back on the same course to see which one makes you faster. Or hired a coach, or gotten a good bike fit. Or made sure to get multiple preride laps in on a race course. Or tried a dropper post to see if it helps you go faster and save energy on the descents (it’s an extra 250g, you know…) You break and wear out stuff all the time or have to make do with sub-par suspension or brakes or tires because you buy parts based on weight.

You don’t care about being *faster* (or having more fun), you care about how light your bike is. And that’s crazy.

Here’s what I think the problem is: grams are crazy small units. But they’re *discrete* units. You can weigh and count and measure them and quantitatively compare them. There is no uncertainty about whether or not one stem cap is lighter than another. You can add up the grams in your head as you fall asleep at night (no joke, I used to do this as an exercise to help fall asleep!)

In other words, grams are a terrible trap for your geeky brain. They lure you with their hard numerical precision and you start to enjoy adding them up (and even more, subtracting them). But they don’t really matter. It’s like spending your time counting pennies to figure out your net worth.

So as an exercise, try this: think of your bike weight in pounds. Period. Round up or down if needed. So maybe you have a 22 pound bike. If it’s 21.8, that still counts as 22, because for all practical purposes that .2 pounds doesn’t matter. Never think about grams again. Because grams don’t matter. Then go buy a really nice suspension fork and some decent tires and go kick some ass.

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