Tuesday, August 12, 2014

Fully converting my road bike into a stationary bike

When I first started getting into shape a few years ago, I was briefly indifferent between running and biking. Running had the advantage of being the most efficient workout from a calorie-burning perspective (I was trying to lose some weight) while biking offered the advantage of being more useful as a means of daily transportation.

I realize that it's not a "one or the other" situation. Duathlons involve running and biking, and of course if you throw in swimming, you get a triathlon. However, I fairly quickly gravitated more strongly toward running. Among other things, biking outside seems much less safe than running does.

Sunlite F2 bike trainer
My bike didn't become completely useless, though. One Christmas, my wife gave me a bike trainer as a present. Your bike's back wheel presses against a roller, allowing you to pedal in place. The roller's resistance can be cranked up to make the workout tougher, although from the Amazon reviews, it seems like serious cyclists don't think it provides enough tension to simulate steep hills.

I do occasionally ride the true stationary bikes at the gym, but there's a lot to be said about having my own stationary bike (in effect) at home. When we were snowed in earlier this year,* I was sooooo grateful that my wife had had the foresight to give me that trainer. (I did sneak outside for a snow run on a day when the conditions were tolerable - i.e., the snow was packed and dry.) In addition, if I'm not able to get in a run on a given day, at least I can sneak in some cardio/endurance even if I have Mr. Mom duties.**
* Having lived in the Midwest, I know what "real" snowfall looks like, and what we get in the Pacific Northwest isn't real by those standards. On the other hand, it's much hillier here, and it snows so infrequently that our cities just don't invest in enough snow removal equipment. Accordingly, just a couple of inches of snow will shut the cities down.
** Why don't I just get a treadmill, you might ask, especially given the title of this blog? For one thing, that trainer costs under $100, and I already had my bike. A good treadmill costs at least $2000, plus I would put a lot of miles on one - i.e., a lot of wear and tear. I'm happier letting the gym take care of maintenance, repairs, etc.
The one annoying thing about riding my (stationary) bike at home was that I had no way of knowing how far I "rode," whereas the stationary bikes in the gym at least provide digital readouts. Now, I don't take biking seriously the way I do with running, where I keep track of miles run on each workout, but I am still enough of a data nerd to be interested in such information.

Sigma Sport BC 400
Voila, the solution appeared the other day, when I took my kids to the local chain sporting goods store to buy my younger son a new bike helmet and my older son his own bike gloves. I needed to spend some more money to be able to use a coupon from the Entertainment coupon book, and I happened to come across a low-end bike computer by Sigma Sport. I think it's a pretty old model and it's not very fancy, but it had just the right features for my purposes: time, distance, and average speed. (Note: the "instruction" manual for this bike computer was close to incomprehensible. Fortunately, it wasn't too hard to set up.)

Now, the big obstacle I found is that the bike computer is generally hooked up so that its sensor reads the front tire's rotation. There is a magnetic sensor connected to the computer through a wire, and then there is another magnetic piece that you clip to a spoke on the wheel. When the magnets come into near contact, the computer reads a revolution.

I couldn't hook things up that way for what I wanted to do, since my front tire doesn't rotate at all. I had to get the sensor on my back tire. That opened up a couple of problems:

1) the back tire seems farther from the frame than the front tire - too far for the magnetic sensor: Yes, the sensor has to be no more than 5 mm (i.e., around 0.2 inches) from the magnetic piece on the spoke. It took me a bit of trial and error of waving the sensor by the magnet to see how close they had to be to trip the sensor, and then adding padding (folded up paper) between the sensor and the frame to close the gap.

2) the wire from the sensor to the computer was too short to reach the handlebars: Since you don't want the wire dangling loosely from your bike, just waiting to be pulled free when you snag on it while getting off the bike, you can't connect it in a straight line. The wire needs to follow the bike frame, which further cuts down on usable length, and anyway, since the expectation is that it's monitoring your front tire, the wire was too short for me. I ended up attaching it to the side of the top bar in the triangle frame. This means I can't really see the elapsed measurements while I'm riding; I have to get off the bike to see how far I've gone, etc. That's suboptimal but tolerable; I can tell the elapsed time on my sports watch, and I'm not training for biking.

All in all, I'm pleased with having been able to set up the computer for my purposes. I put it through a test spin tonight and found that it worked, although apparently I bike more slowly than I thought....

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