2009-05-14

Routine Maintenance

I enjoy riding bikes. I also enjoy hacking on bikes: building them, taking them apart, rebuilding them, and trying new parts and configurations. These are definitely two completely separate activities, and there's no reason anyone needs to enjoy both of them, if they happen to enjoy one of them.

On the proverbial third hand, I really don't enjoy bicycle maintenance, and so I tend to ignore it. I may not ignore it as much as some other folks do, since my well stocked basement makes it a lot easier than taking my bike to a shop once per year. But it's definitely not in the same category as "bike hacking," as subtle as that may seem: it's the difference between "maintaining the old" and "creating the new."

I ride probably between 3500 and 4000 miles per year. My bikes require regular maintenance to maintain their current performance, as well as to avoid future costly problems. This is a summary of what I do with my bike (whether I like it or not) and when.

A few maintenance items are necessary frequently enough that I'm tempted to not mention them: keep air in your tires (but maybe not as much as you think you need), and patch holes in your tubes whenever necessary.

The single most important maintenance I perform (though not the most frequent) is oiling, cleaning, and replacing my chain. If I were willing to thoroughly clean my chain more often, I could replace it less often, but it's still unlikely I could get more than 2000-3000 miles out of a chain without wearing out other more expensive components. So, I oil my chain when it squeaks, I clean and degrease it when it's convenient, and I replace it when it has stretched by at least .75% of its total length. This is usually around 1000-2000 miles, or one chain per year on each of my summer and winter bikes.

"Chain lube" is a holy war in bicycle maintenance circles. My summary is: it hardly matters what lubricant you use, as long as you use something. Anything from melted paraffin, to olive oil, or purpose-made chain lubricants will do just fine (but WD-40 won't! See also: holy war). Apply oil to the entire chain, let it sit, and wipe off the excess (I rarely do that last step, but it keeps your chain from attracting dust and dirt).

Chain cleaning is another holy war, and again, the summary is: you're better off cleaning your chain than not cleaning it. If you listened to manufacturers' recommendations, you couldn't ride five miles without completely disassembling your chain and cleaning and oiling every individual part. But at under $20 per chain, I err on the side of replacement. The only other point worth making is that high quality fenders help keep your chain a lot cleaner.

I use a tool to measure chain stretch, but you can also use a ruler. Two links of chain are one inch in length, measured from the pin center to pin center. If 24 links of chain are more than 1/16" longer than a foot, then it's time to replace your chain. If they're more than 1/8" longer than a foot, then you've probably already worn out your chainwheels and/or rear cogs: even if you replace your chain, you'll likely continue to have shifting problems. At this point, I generally recommend doing nothing at all, until you can't stand the crappy shifting anymore. Then, just replace the chain, all chainwheels, and the freewheel or cassette. (Or, donate your bike and get a new one: in some cases, this is the cheaper option.)

A chain is made of flat plates and round pins: the plates rub against the pins, and eventually wear them out. Lubrication and a lack of debris delays this wear, but doesn't eliminate it. When the pins wear out, the chain increases in length. As a chain "stretches," it fits the cogs less and less perfectly, and wears them out at a greatly increased rate. Sheldon Brown has an excellent article about chain stretch (with pictures!), but the crux is: clean your chain often, and replace it regularly.

In hilly Pittsburgh, the next most important maintenance I do is replacing brake pads. This is easy: just before they wear down to the metal bits, replace them. I probably replace front pads once every year or so on each bike: 2000 miles or so. The rear pads last a lot longer, because rear brakes are nearly useless. They're good for slowing down, but you should always use your front brakes ("carefully," says the seasoned handlebar-diver) if you need to stop quickly. The life you get out of your brake pads depends a lot on how much you use them, what they're made of, and how thick they were to start with.

I guess I buy durable tires, or I've been a bit fickle with choosing a new style of tire before the old ones are worn out, but I haven't managed to wear through a set of tires even after many thousands of miles. I have a few pairs which are coming close, but they may be more likely to burst from too many glass cuts than from running out of rubber. Although tires seem like the top of the list for replacement items, they last a lot longer than you might expect.

My current favorite tire is the Panaracer Pasela. These are relatively fast and comfortable tires, quite durable, and inexpensive: overall, a very good value. They also come in many sizes: 27", 700c, and 26", in a variety of widths. They're very good for "mostly on-road" riding.

For most other parts, I replace them only when they're broken or not working as well as I'd hope. When I was young, I went through brake cables like crazy, but I haven't had to replace any brake or shifting cables due to wear recently.

As for other maintenance, the main topic is bearings and their associated grease. I generally repack all bearings once when I rebuild a bike, but in most cases I haven't had to repack them again after that. I did recently repack a front hub and replace some of the balls (on a fairly new wheel), because it was making a horrifying grinding noise. I've switched to using cartridge bearing bottom brackets, which last a long time but can't be repacked once they go bad. I haven't had to replace any bearings, but I've had several locking cups/rings break and cause trouble. In general, all of these parts can go thousands of miles and many years without maintenance, unless you dump your bike in the river or ride through sand dunes regularly.

I don't bother with keeping my wheels straight (truing them) unless I have the wheel off anyway, or I notice a problem: either a wobble when I'm riding, or brakes rubbing. Since I started using higher quality, properly tensioned wheels, this has basically become a non-issue (except when I stick my foot in the spokes or something).

In summary, my experience is that required regular bike maintenance is not very substantial, but it is most necessary where you may least expect it. Keep an eye on your chain, because you can run into costly repairs if you neglect it for too long.

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