Our bike shop expert and incredibly talented wordsmith, Michael Tanner, is back to give us a rundown on basic bike parts and how to take care of your bike from handlebar to hub.
As a fan of both dad-speak and a good melodious absurdity, I won't judge you if you call that piece of aluminum attached to the middle of your handlebars a gooseneck rather than a stem. But if you want to present a more pro persona on the road, or save a little time in translation at the shop, it can't hurt to know what's what on your bike, and which parts you should really keep an eye on.
Up front: This is where the steering happens, obviously, and where if anything goes wrong it can go wrong in a calamitous, face-first sort of way, so it's worth inspecting carefully for bends, cracks and chips. Leading the way is the fork(1), starting at the slots, called dropouts(2, see below), where the wheel attaches. The fork legs converge at the steerer tube(3), which sits surreptitiously inside the head tube(4) of the bike's frame, and spins within it on the headset(5). Up top the aforementioned stem(6) and handlebar(6) rest, holding the brake levers(7) and the shifters(8) for the gears. Squeeze that left-hand brake while you're up there and rock the bike back and forth. If there's a clunking noise, the headset is loose, and you should come see us.
Framed: The body of the bike generally consists of the double-triangle, or diamond, that lends it its incredible structural strength, and makes one a legitimate romantic gift. The top tube(9) and seat tube(10) are exactly where the names imply -- you spend lots of time staring at the former so that's where inspirational stickers go, and the latter is where the bike's size is measured. The diagonal down tube(11) connects them and should be checked for damage after a collision. The stays(12) proceed from the seat tube to the rear dropouts(2), which hold the back wheel. Aficionados refer to the dubiously padded perch protruding from the top of the frame as the saddle(13), because we like to see ourselves as modern cowboys, ranging free—but "seat" works too.
The dirty bits: The drivetrain entails the chain(14) and the front sprockets, called chainrings(15), not to be confused with the rear ones, known as cogs(16). The pedals(17) rotate on the the cranks(18), which spin on the bottom bracket, the source of 60% of mysterious bike noises, and the apparent suspect in 95%. The chain needs frequent attention and lubrication, but conveniently will remind you by squeaking loudly or turning rust orange. The derailleurs(19), front and rear, are the little mechanisms that move the chain among the gears.
Stop it! Brakes (20) come in either the rim style in which rubber pads grip the rim of the wheel itself, as still found on most kids', hybrid and and road bikes, or disc versions, which are stopped by grabbing a small secondary disc, or rotor (not found on the pictured bike), attached to the hub(21), as on a motorcycle or car, and now found on most mountain bikes and increasingly on all other formats of cycle. If you're really bored—or want to be—ask two roadies about the relative merits of disc or rim brakes on racing bikes. Either way, since these are what keep you from launching off cliffs etc, give them a regular check for alignment, pad wear, and cable fray.
Round and round: Wheels are a constant source of nomenclatural confusion, so pay attention. The rims(22) are just the outside hoop of the wheel where the tire(23) sits, attached to the hub(21) by the spokes(24). Most bikes have quick-release skewers(25) that run through the axles and attach the hub to the bike's frame. The tire is the outer layer of rubber that surrounds the inner tube, which holds the air and is usually all that needs replacement in the event of a flat, but it's smart to check the tire itself for cuts, scrapes and flat spots for safety. Also, top off your air pressure at least once a week to keep things rolling fast and avoid pinch flats.
Ka-boing: Most mountain bikes are going to have some form of suspension, at least in the front. That would be provided by a suspension fork(26), whose lowers hold the wheel and slide on its stanchions(27). Out back the front triangle of the frame is connected to the rear triangle and wheel by a series of pivots and links, with the movement controlled by the shock(28). Old-school tough guys just use their knees.
Now just add the grimy black fingernails, and you’re halfway to convingly posing as an expert. To get the full mechanic’s manicure (machanicure?), stop by your local Basement for one of our bike maintenance classes.