Chevy Chase made the phrase famous in Fletch, but my friend Dan, with my first guest post, tells you exactly what ball bearings are and why “it’s all ball bearings these days.”
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In a perfect world, riding your bike would always be a pleasure. Every day would be 75 and sunny, the trails or roads would be empty, and you’d never experience any kind of mechanical breakdown. But as we all know it’s rarely 75 and sunny, the trails and roads never seem to be empty, and I don’t know one person who’s never experienced a breakdown. And while we could all trade horror stories about the worst experiences we’ve had (mine involves a separated shoulder and a Bible-toting Mormon on a trail in the mountains of Utah, but we won’t dwell on that), I would wager that for the most part our bikes have been pretty reliable companions. Sure we’ll get mad at them from time to time, and blame them for things that aren’t their fault (most likely it’s you, not the bike, that’s the reason you didn’t make it up that climb), but what’s a relationship without a little of that? The kinship I’ve felt with my bikes over the years has rivaled some of the best relationships I’ve had with certain people (which some might say is a symptom of a bigger problem), and I know that I don’t take nearly enough time to step back and appreciate what they’ve brought to my life. I also rarely, if ever, take the time to consider the technology that enables me to do what I love to do.
As simple as they look, bikes are ingeniously put-together pieces of machinery. And while I don’t have any mechanical skills or formal education on which to base the following statement, I think there’s one technology above all, which has arguably been around since at least the building of the ancient pyramids that makes them so efficient.
More than 5,000 years ago the pharaohs of Egypt commissioned the building of those pyramids as their burial tombs, using granite blocks that on average weighed over two tons each. Moving stones that size was obviously no easy feat, and it’s believed that Egyptians developed a system where they would roll the blocks over a series of logs, thereby reducing the friction between the blocks and the ground, until they reached their final destination.
On a much smaller scale, that same principal is used in most of the moving parts of bikes built today. Anywhere that there’s a connection on your bike between a turning and a non-turning part, there is most likely a collection of tiny metal balls that help reduce the friction, and make the movement between those parts more efficient. Those are called ball bearings, and if you’ve ever been in a bike shop, or around a bunch of gearheads, or are a fan of ‘Fletch’ and you’ve heard those words being thrown around, that is what’s being talked about. They’re most commonly found in headsets (where the handlebars meet the frame), freewheels (all those cogs on your rear wheel), hubs (the beefy thing in the center of your wheels that the spokes are attached to) and bottom brackets (the section at the bottom of your bike where all the tubes meet and around which the pedal cranks revolve). In theory they’re supposed to reduce all friction between moving parts, but since that’s generally a scientific impossibility, they’re designed to create the least amount of friction as possible.
Up until about twenty years ago, there was generally one type of ball bearing used on bikes, the cup-and-cone bearing. The main advantage of this type of bearing was that it could be disassembled and rebuilt if dirt, grime or moisture ever found their way into the bearing. But that in a sense was also its disadvantage, in that dirt, grime and moisture would often find their way into these bearings, necessitating disassembly and replacement. Many, many bikes on the road today still employ cup-and-cone bearings, and it’s recommended that the bearings be serviced at least once a year, although if you’re riding just a couple of times a week or less, you could probably get by with servicing them less frequently.
The other, and more recently developed type of bearing is the cartridge bearing (sometimes referred to as a “sealed-cartridge” bearing), which is used in many of the better bikes built in the past ten years or so. If you’ve ever done any in-line skating, you’ve taken advantage of this type of bearing; they’re what are used in the wheels. The concept behind this type of bearing is that all of the ball bearings are housed in a self-contained unit, which prevents dirt and moisture from contacting them. They’re generally more durable than cup-and-cone bearings, and are becoming more and more common on all levels of bikes being built today. The only downside is that when something goes wrong with this type of bearing, it’s next to impossible to take apart and rebuild, and you wind up needing to replace the whole unit. That can be a little more expensive than repairing the cup-and-cone type, but you shouldn’t ever really run into that problem if the bearings are well-made and working properly, which these days is usually the case.
Regardless of what type of bearings are in your bike, there is one simple step you can take to make sure the bearings don’t wear down before their time. Clean your bike after every ride. Just don’t ever, ever power-wash it. Everyone’s felt the temptation after a ride to just turn the garden hose onto their bike and blast the dirt away, but while you’re doing that, you’re also increasing the likelihood of water contaminating the bearings, not to mention blasting away the grease that keeps the moving parts lubricated. (On a related note, if you ever work in a kitchen and have the opportunity to put your bike in an industrial dishwasher, don’t. That’s a bad idea on multiple levels.) The proper way to clean your bike is simply with a bucket and a rag. It may take ten more minutes to do it that way, but your bike will be much happier, and rather than cleaning it from a distance, you’ll be able to get right down next to it and get to know it and all its parts a little better.
All ball bearings, however well made, will eventually begin to wear down, due to use, dirt, or other factors. If you ever hear or feel any grinding in your handlebars or pedals, that could be an indication that your bearings might be wearing down. It could just be that there’s dirt at the base of your bars, or where the pedal cranks meet the bottom bracket, but if after cleaning your bike you still hear or feel grinding, you’d probably be better off getting them checked out as soon as you can, to prevent further damage. If they’re cup-and cone bearings, most reputable bike shops still carry the parts needed to rebuild them, and will know what you’re talking about if you tell them you think you’re bearings might be shot. If they’re cartridge bearings, you may wind up needing to have them replaced. Either way, that’s a small price to pay compared to what could happen if they fail when you’re out on the trail.