It depends on what kind of commuting you do. There are people who commute like they are on a multi-day tour: two panniers filled with changes of clothes, lunch, etc., riding 15 or 20 miles each way (that pretty much describes me as a commuter). Other people live 3 miles from work and don't need to carry a change of clothes because of the nature of their work.
One of the bicycle mags actually did an article that followed some Wal-Mart bikes around, and for the latter kind of commuter, people riding short distances, at low speeds, lightly loaded and (eek!) riding on sidewalks, a basic big box bike is more than up to the task and will last pretty well. When it comes time for maintenance and repair, though, it just isn't worth it. So you ride the bike into the ground, turn around and buy another one. I mean, a lot of us put the cost of that bike into our gas tanks ever 2 or 3 weeks and never think twice about it.
These bikes are so inexpensive that it doesn't matter if they last 20 years. If you buy the bike in the spring and it makes it through following winter, you can just throw it away the following spring and get another one for $100. Paying that much for transportation for a whole year is a bargain.
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I stop for people / whose right of way I honor / but not for no one.
Originally Posted by
bragi "However, it's never a good idea to overgeneralize."