Sprockets for Dummies

Sprockets on a bicycle 

When it comes to sharing information – the buzzphrase in the '90s was "technology transfer" – we've found that it helps if the sharer knows more about the topic at hand than the sharee. Unfortunately, the balance of knowledge is too often equal or even reversed when penny-grubbing freelancers get involved. For an example, we need look no further than today's DotD nominee, WiseGEEK.com writer Maggie Worth. Her contribution to the stupidification of the internet arrives in the form of the post, "What Is a Sprocket Wheel?" (now at AboutMechanics.com... with editing assistance from Jenn Walker).

We suspect that Worth ran straight to the dictionary entry for "sprocket" and, in part, reworded it to get her introduction:

"A sprocket wheel is a wheel or disc, usually thin, that contains a series of teeth around its outer perimeter. These teeth are created to engage the links of a chain. Turning the wheel causes the chain to advance, usually activating either another sprocket wheel or some other type of mechanism. Such wheels are used frequently in manufacturing, but are also found in common consumer items, most notably bicycles."

Yeah, that works OK, although Wikipedia goes into a bit more depth and mentions that sprockets engage with belts or tapes as well; anything with indentations that match the teeth on the disc.

That shortcoming's not why we flagged Maggie (and Jenn) for this entry, however. No, we flagged it because of the monumentally stupid paragraph they published describing the use of sprockets on bicycles:

"Most bicycles have two such wheels. One sprocket wheel is attached to the front wheel of the bike, while the other is attached to the rear wheel, with a chain connecting the two wheels. The links of the chain are made to engage with the teeth on both wheels so that when one turns, the other also turns. The pedals are connected to one of the wheels."

Wait, what? There's a "sprocket wheel... attached to the front wheel of the bike"? Is this moron kidding? Has she looked at a bicycle since she got her driver's license? No, Maggie, there are no sprockets on the front wheel of a bicycle!¹ The pedals and chainwheels (the "front sprockets") are mounted on a shaft that runs through the bottom bracket of the bike.

Worth has more to say that is equally stupid:

"When the rider turns the pedals, the first sprocket wheel turns... [which] makes the front wheel of the bicycle turn..." "If the chain disengages with the teeth of either of the sprocket wheels, the entire mechanism ceases to work. While the pedals will still turn one wheel, the other will stop and the bike will not move forward." We also laughed uncontrollably at the image accompanying Worth's opus (reproduced above), which included the caption "Bicycles commonly have two sprocket wheels." Our Dumbass of the Day can't even count: in that photograph (which, by the way, is printed backwards: bicycle derailleurs are on the right side of the frame, not the left), the bicycle has seven sprockets in the cluster plus at least one chainwheel. Only so-called "fixie" bicycles have two sprockets. Sheesh.

¹ Yes, some recumbent bicycles do have front-wheel drive, but in that case there are no sprockets on the rear wheels. Our flabbergasted expression stands.

copyright © 2018-2022 scmrak

SE - BICYCLES