Thursday, October 12, 2017

Installing a Derailleur for a Dummy Cyclist

shimano altus rear derailleur
Shimano Altus rear derailleur
If you ride a bicycle – not one of those "fixies" favored by man-bun-toting hipsters, though – you've probably noticed a contraption by the back wheel called a derailleur. For what it's worth, there's also a contraption near the pedals, also called a derailleur. Whether it's been trashed in a wreck or you're just upgrading the components, you might want to take on installing a new drivetrain, including a new derailleur. Heaven help you, however, if you think eHow.com's Tammie Painter managed to compile useful "Shimano Altus Derailleur Installation Instructions" in her crapalicious post (moved to SportsRec.com by Leaf Group).

Painter opened by informing us that
"Altus is a bicycle component group manufactured by Shimano. A component group includes nearly all parts of the bike except the frame, seat, wheels and forks."
A) we already know it's a Shimano product, Tammie! B) you're missing pedals, chain, stem, handlebars, seat post, cables, tires... and C) don't you think it important that the Altus group is an entry-level MTB groupset? We did...

Now, Painter managed to come up with a set of installation instructions somewhere, sort of: she perused the technical spec sheet for the entire groupset, which Shimano has since removed from their website. Based on this worksheet, which is intended for professional mechanics, i.e., people who know what they're doing (that definitely leaves out Painter) and is not installation instructions, she instructed her readers to
"Locate and remove the hangar bolt (the large bolt at the top) from the rear derailleur. Attach the rear derailleur to the bike frame in the hole near your cassette (rear gears). The arm of the derailleur with the jockey wheels hangs downward. Insert the bolt and tighten it until the derailleur is secure."
Tammie, Tammie, Tammie: A), it's not a "hangar" bolt, it's a hanger bolt – the derailleur hangs from it... B) you don't do this with the wheel in place, and C) what's the proper torque?

Never mind the questions... Painter then told her readers to install the chain and shift cables. Although she carefully instructed them to put an end cap on the cables, she completely ignored the cable housings, not to mention the routing of the cables. Oh, well, you'll figure that out, right?

One last deficiency, but it's a doozy. Those of us who've done any work at all on bikes with derailleurs know that every time you install a new chain or new cable on a bike with indexed shifters (such as the Altus), you have to adjust the high and low limit screws on both derailleurs or the damned thing won't shift. Did Painter say anything about that? No, most likely because our Dumbass of the Day didn't know anything about derailleurs.     
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DD - BICYCLES

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