My bicycle is not shifting smoothly. The problem has developed over many months. I’ve adjusted the cables repeatedly, without success.
I received some not so bad news today. I took my bicycle into a neighborhood bike shop. The crank teeth are worn down, as are the back sprockets and the chain. This will be a substantial repair for a bike– more than $100. This should put my bicycle into perfect riding shape. I quickly agreed to go ahead with the repairs.
As I’ve described before, I often use a bicycle to commute to work. I put almost 1,500 miles of wear on the bike every year. Riding a bike (rather than driving a car) provides many benefits, including improved health and less stress on the environment. I’ve described those benefits at this comprehensive post. I also note that the IRS now reimburses workers about 50 cents per mile for use of a car. Based on the IRS rates, I save about $750 per year by merely riding a bicycle to work.
To put my “big” bicycle repair bill in even better perspective, my neighbor (who drives a large gas-chugging vehicle) just told me that he now pays more than $100 to fill his tank one time. He fills up that tank once every week. My major bike repairs were needed for the first time after constant use of the bike over a period of seven years.
Here’s one other thing to consider. It is often possible to ride a bike rather than driving a car/truck/SUV. Most trips many people take require traveling only 5 miles from their residence, an easy distance to cover with a bicycle.
With these thoughts, in mind, I decided to file this post to remind others of the many benefits of riding bicycles whenever possible. Again, for a more fact-filled version of this post, check out this previous post.
you probably messed up your crank teeth because you failed to replace your chain when you should have. an ounce of prevention…
Suggestion: Your point is a good one. I should have changed my chain. Here's a bit of background: I was taking the bike in for a tune-up and inspection each year to a reputable-seeming bike shop (not the one that is now fixing the problem). This was a $60 tune-up and inspection, so I expected them to tell me everything I needed to do and I would have done everything they suggested. They never once mentioned that I should replace my chain.
I'm disappointed that they didn't do a better job, but it's certainly not the end of the world.
A sometimes serious, sometimes humorous, sometimes just plain weird discussion of chain and sprocket wear here: http://groups.google.com/group/rec.bicycles.tech/…
"I’m disappointed that they didn’t do a better job, but it’s certainly not the end of the world."
When the end of the world does come, will there still be a Heaven?
Commuting puts a relatively high amount of wear on bicycle drivetrains, compared to drivetrains on bikes that are only ridden on sunny days. Rain, sand, salt, road debris, etc., get into the chain links and cause a lot of wear. Remember that grinding paste is just a mixture of grit and oil — the same thing that accumulates on your chain. One thing that helps is to clean and lube the chain frequently — say, once a week — using one of those chain cleaning gismos that clips onto the chain (e.g., Park Tool CM-5) and that flushes out the grit that's inside the rollers. It's not enough to just add lube and it's not enough to just wipe the dirt from the external surface of the chain links — you need to clean out the crud that's down inside the rollers.
Damage to cogs and chainrings happens when the chain "stretches." I've put that in quotes, because the plates that hold the chain together don't actually stretch (none of us weighs enough to stress the steel chain plates beyond their yield point); what happens is that when the rollers wear on the inside, a gap opens between the rollers and the pins, and this gap allows the chain pins to pull farther apart than on a new chain. This causes an apparent elongation of the chain that accelerates wear on the cogs and chainrings, because the chain no longer meshes evenly with all the gear teeth (thus spreading the wear evenly among many teeth); instead, the pedaling force becomes concentrated on only the first few links of the chain that contact the gears. This greatly increases the contact pressure between the chain and gears which, when combined with the aforementioned grinding paste effect, rapidly wears out the gears. The cogs, having fewer teeth than the chainrings, wear out first, but the chainrings will eventually wear out, too.
To minimize wear on the gears, it's prudent to not only clean the chain frequently, but to also replace the chain when it "stretches" too much. Park Tool makes a $10 gauge (the CC-3 Chain Checker) that measures chain wear and will indicate when the chain needs replacing. It's a worthwhile tool to own, because quality chains cost more than $10, so the gauge helps avoid replacing chains too often.
just fyi, on my road bike i get about 1,000 miles out of a chain. that means about 4 chain replacements/summer. still a bargain not to pay for gas, and you get all those endorphin highs for free.