Mostly recaps of two wheeled rambles through the countryside, but sometimes thoughts on other things.

Sunday, February 10, 2013

It's All About The Numbers

I started as an adult to ride a bike around 2000 or 2001. I had fallen waaaaay out of the track and wrestling team shape of my schoolboy days and I was looking to bribe myself to get outside and move around more. I thought that something that I'd always wanted as a kid but rarely had, a shiny new bicycle, might do the trick.  Indeed it did, as I found myself bitten by the biking bug in a serious way. It was more than just the joy of turning the pedals and listening to the sounds of the chain over the gear teeth, the rubber responding to minor irregularities of road surface, or the jingle jangle of something that should have been more securely fastened, but was now banging out of sight, but not out of hearing. I found myself attracted to the NUMBERS of a bike.

Many riders I know deal with numbers on some scale or other. They know how much their bike weighs. At least as it is presented by the bike advertisers, and lacking things like pedals, water bottles, a tool kit, pump, spare tube, Garmin, a comfortable saddle, what have you. The may know the tire size and pressure, how many gears they have and the size frame they ride. They know how many miles they've ridden this year and at what average speed. How many feet of elevation they've climbed and  what % grade as well.

Considerably fewer pay attention to the numbers OF cycling. Bike geometry; which governs fit and affects comfort, and handling (Rake). Drive-train gear ratios, chain length, shift range of various deraillers. How changing the tire size and air pressure affects comfort, speed  and handling (Trail). Many don't know their own body measurements, as relates to the bike, to get the best size frame, proper width handlebars, correct length of crank arms, comfortable space between the pedals (Q-factor). Few pay much attention to the comfort details like proper saddle selection and set up, correct stem height, length, and how much padding do or don;t you need on handlebars?

All of this comes to mind from an on the ride conversation with a new rider on the club Saturday outing. A fit woman who focuses on triathlons, Jan was working on her bike fitness this particular day. I noticed that she was turning about 55 rpm in a huge gear, maybe a 53:14 or so. When I asked her about it, she said she had read that a slow cadence in a tall gear was the most efficient way to go. Now, toss out any idea on cycling and surely you will find someone to argue more than one point of view. This one though is pretty well settled in the racing and touring communities, 72RPM is the Rubicon between pumping or mashing and spinning. Spinning is generally held to be more efficient, easier on the joints and better when encountering headwinds or hills. Road racers generally spin around 95 RPM and up to 105 for a pursuit or attack. Yes, there may be times that you just feel like slowly tromping up a hill, but on a long ride, you do much better in an easier gear at higher rpm. It's how 4 cylinder imports first challenged domestic V8s on the road. I've worked to get my spin up to 84 avg and as I race no one, that works for me.

Comfort on a bike is again a very personal situation. We are all made differently, and our sense of comfort varies as well. There are just three contact areas between you and your bike. Your hands, your bottom, and your feet. I am happiest when most of the weight is on my bottom, evenly distributed over a form fitting (for me, leather) saddle. I need no chamois pad in the shorts and therefore no chamois lube either. By the way, if you wear padded shorts, you do not wear underpants. You put chamois lube on you or the shorts to prevent chafing. If you do NOT wear padded shorts (like me) you DO wear underwear. This allows the layers of fabric to slide on each other. Cotton is a bad choice in any of these cases, as once it gets wet from perspiration, it drags on your skin. Thin wool base layers are my choice, but wicking synthetics (Technical fabrics) work well too. Cotton is fine for a 2 mile casual pedal for a Starbucks however, where sweat is not likely to be a problem.

When I am sitting on the saddle, I can pull my arms away from the handlebars without falling forward, and my arms are relaxed when on the bars. This keeps my hands and shoulders from getting tired and puts little load on my back. That also means there is no padding needed on the handlebars or in the gloves. Padding is often an answer to a problem that could also be solved by changing the bike set up.

More limber riders can set up so their backs are parallel to the ground, which is speedy and aerodynamic. This means a higher seat and lower handle bars. My 45 deg incline set up gives me a better look around, at the expense of speed. Also, my limber days are behind me. My handlebars run about 2" above my saddle.

To get the right frame size, start with your pubic bone height. Here's a link on how to measure it.

Once you have this you can start with a proper size frame and dial in as little or as much of the rest as desired. I'm not going to attempt a bike fit compendium here, but I'll happily answer any questions I can, and help anyone find what works for them.

So what  kind of gearing do you want? Are you clipping in or pedaling free, or something in between?  More on all that next time.

And since Jan turns out to have an eye for a picture, here is one she took on our ride yesterday.

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