In This Chapter
^ Getting clear on cassettes and freewheels ^ Inspecting, cleaning, and lubricating cassettes and freewheels ^ Removing and installing cassettes and freewheels
ne of the most enjoyable experiences when riding is the exhilaration that comes after having reached the top of a tall peak, when the downhill begins almost immediately and you’re rewarded with a long descent. The satisfaction of having conquered the ascent, the relief of being able to rest your legs for a moment, and the rush of coasting at high speed with the wind in your face are what keeps people coming back for the climb.
What makes the coasting part possible is the topic of this chapter. Freewheels and cassettes are like the clutch on your car — disengage it and the car is rolls free in neutral. In a bike’s case, stopping pedaling does the trick. In this chapter, we fill you in on some of the basics of how the freewheel and cassette work and how coasting is possible, as well as everything you need to know about their maintenance, including inspecting, removing, and reinstalling them.
The Dirt on Freewheels and Cassettes
Think about a kid’s fixed-gear bike: Every time the rear wheel spins, the pedals and cranks rotate with it or the front wheel. For young children, this isn’t a big deal — they usually don’t ride very fast, and they have more energy than they know what to do with. However, if your bike worked the same way and you were riding down a hill at a high rate of speed, your legs would have to keep up with the pedals and cranks, which would be spinning at a furious rate. Talk about dangerous.
Fortunately, modern bikes have a clutch system that allows you to coast when you stop pedaling, and move forward again by pedaling when you slow down. This system is made up of either a freewheel or a cassette, the subject of this section.
To determine whether you have a freewheel or cassette, examine the smallest cog. If there is a screw-on lock ring with the word lock on it, which rotates with the cogs when you spin the freewheel, you probably have a cassette. If in doubt, take your bike to your local bike shop and ask the people there.