from Rookie’s keyboard,
Hello, friends
It wouldn’t be a “proper” weekend without a new RJ.com post, right?
I have prepared another post for the cycling rookies out there.
The focus will be on freewheels and their threads, to be specific.
There are two types – multi-cog freewheels and single-cog.
Multi-cog freewheels are a cluster of cogs with a built-in ratcheting mechanism.
The ratcheting mechanism disconnects the freewheel from the hub and allows the cyclist to coast.
Single-cog freewheels operate on the same principle as multi-cog freewheels.
The only difference is that there’s only one cog/gear.
It’s important to know that freewheels are NOT reverse threaded (for some reason many people believe that).
They screw onto the rear hub in a clockwise direction.
The goal is security. When you pedal forward, the rear cogs rotate clockwise and thus tighten the freewheel onto the hub even more.
If the threading was reverse, the pedaling motion would cause the freewheel to untighten and subsequently wobble.
A freewheel on a bike that’s been ridden a long time is often notoriously tight and requires a ton of leverage to remove it. You may need a cheater bar (a pipe that slides onto a regular wrench as an extension).
To uninstall a multi-cog freewheel, you need the following tools:
- A removal tool that matches the splines/notches of the freewheel.
- A wrench
- Extension bar (needed if the freewheel is really tight)
If you have an older freewheel (e.g., Suntour), you must to secure the removal tool to the freewheel via the quick-release.
The wrench or socket are rotated anti-clockwise to untighten the freewheel.
Single-cog Freewheel
Single-cog freewheels also thread onto the rear hub in a clockwise direction too for the same reason.
The removal process is also similar. The only difference is that you will need a different removal tool designed specifically for single-cog freewheels.
One example of such a tool would be the ParkTool FR-6 which removes 4-notch single-speed freewheels.
Disassembling a Freewheel
To disassemble a freewhee, you have to remove the lockring holding the mechanism together.
The ring is reverse-threaded and unscrews clockwise.
Theoretically, the lockring is removed via a spanner wrench, but more often than not, you will have tap it with a punch or a nail.
After the freewheel is free, you can use a spanner wrench made out of a spoke such as the one in the picture to fully untighten the lockring.
If you try to remove the lockring when the freewheel is off the wheel, you won’t be able to because the inner part of the freewheel will spin.
Keep the freewheel on the wheel for the initial untightening (the hardest part).
Fixed-gear Cogs
Some rookies may confuse fixed-gear cogs with a single-speed freewheel.
The two are very different.
A single-speed freewheel has a ratcheting mechanism which disconnects the freewheel from the hub when pedaling backward or coasting.
Hence a single-speed freewheel does not need a lockring to hold it tight to the hub.
Pedaling keeps the freewheel secure, and when the rider backpedals, the cog is disconnected from the hub, and there’s no chance for the freewheel to untighten.
A fixed-gear cog does not have a ratcheting mechanism. There is not option to coast. Each attempt to backpedal (or simply stop via the pedals) transfers a lot of force to the cog, the hub, and the wheel.
Since there isn’t a freewheel mechanism to reduce the strain on the cog, there’s a real chance for the cog to untighten.
Fixed-gear cogs come with a lockring which prevents the cog from unscrewing.
The lockring is reverse threaded and tightens counterclockwise so that it cannot untighten during backpedaling.
Pedaling forward tightens the cog, but backward pedaling untightens it. When the lockring is there, the cog has no room to move and thus cannot unscrew even during backpedaling.
Until next time,
Rookie
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