Square taper cranks, also known as cotterless cranks, are a type of crank arm configuration that are relatively common on beginner and other affordable unicycles.

The square taper crank has a cross-sectionally square profile at the hub axle-interface. This streamlines manufacturing as well as installation.

Here are a few things you need to know.

Why Cotterless Cranks Are Common

The main reason cotterless cranks are so common is because they are more affordable to manufacture and require less machining and potentially more basic tooling than alternatives (which will be covered below).

The cost-savings go into the rest of the price of the unicycles that are outfitted with square taper cranks.

Of course, installation is pretty straightforward too, which is another reason that cotterless cranks are common on beginner unicycles.

A Caveat When Installing or Riding a Model with Square Taper Cranks

One thing you need to keep in mind when you are riding a unicycle that has square taper cranks is that you must never ride with the crank arms loose, even a little.

The square cross-section of a cotterless crank is what provides a strong friction fit in the bearing. However, that places a great deal of pressure on the corners.

If the cranks are loose, the corners will not be snug in their fittings and the force of cranking the arms can and will quickly deform the hub-axle interface by rounding off the square corners.

Just a crank or two with loose cotterless crank arms can permanently damage the cranks, and will likely require substantial repair or replacement.

A Stronger Alternative to Square Taper Cranks

The average unicycle owner has more than one. In fact, the average owner usually has somewhere around three.

After they graduate from their first unicycle, they often become interested in other disciplines that require more specialized equipment, like racing, commuting, mountain unicycling (muni riding) or trail riding.

Oftentimes, unicycles made for these more rigorous applications are made with a different style of crank arms called ISIS cranks.

ISIS cranks are a type of splined crank that has a hub-axle interface that, in cross section, looks more like a star.

This configuration increases the surface area between the crank arm and the hub-axle interface, and results in a much stronger fit.

While they must be installed on the proper side, they are also a lot more durable than square taper cranks, and so they are used on higher-end unicycles.

Where to Get Unicycle Parts

Whether you are here for a replacement pair of square taper cranks, or are interested in getting a second, third or even fourth unicycle with stronger, splined ISIS cranks, there’s one place to do it: the aptly-named Unicycle.com.

It’s in the name. They are the authority on all things unicycles and unicycling, as well as odd bikes (they sell penny farthing bikes, for instance).

Whether you’re here for a new ride or just need unicycle parts, check their website first.

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