 Xspeak: Snow Mountain Biking
by Jimi Killen, Winter X Games Snow Mountain Biking researcher
Here is a glossary of Snow Mountain Biking terms:
AFTERMARKET: A component or product that's not included or intended as original equipment.
AIR/OIL: A type of shock absorber that uses air for the spring and oil for damping.
ALUMINUM: Very common material. A bicycle frame material that is abundant and inexpensive. Its main drawback is that aluminum is not terribly strong so frames made from aluminum require tubes of substantial diameter. The advantage of aluminum is it allows for creative frame designs. Most downhill bikes are aluminum.
ANODIZATION: A process that hardens and seals metal against corrosion. It can also be used to dye metal colors such as blue, red or black.
BAR-ENDS: Attachments that mount on the ends of a handlebar. Bar-ends allow more leverage when climbing and more hand positions when cruising.
BLACK BOX SYSTEM: Referring to a black computer box that is mounted on the bicycle. The black box acquires data through various sensors to be downloaded then analyzed, determining proper bike tuning and adjustments.
BOTTOM BRACKET: The bottom bracket is where the downtube, seat tube and chainstays come together. A spindle passes through the bottom bracket, and the cranks attach to the spindle.
BOTTOM BRACKET HEIGHT: The distance between the ground and the center of the bottom bracket spindle. Taller bottom brackets offer more obstacle clearance but tend to be less stable than lower bottom brackets.
BUTTING: A process where the diameter or thickness is increased. Frame tubing that is butted has its wall thickness or diameter increased.
CANTILEVER BRAKES: Traditional bike brakes, one mounted on the frame or fork on either side of the wheel. Pulled together, and against the rim, by a common cable tightened by squeezing brake lever on handlebar.
CARBON FIBER: A material comprised of carbon and epoxy-impregnated fabric. Carbon fiber is the most light-weight frame material, with the highest strength-to-weight ratio. Since downhill riders aren't typically concerned with weight, not a popular downhill frame material.
CHAINSTAY: The tubes that connect the rear dropouts to the bottom bracket.
CHROME-MOLY STEEL: A steel alloy that contains chromium and molybdenum. A super strong frame material that's easy to work with, but heavy.
CLIPLESS PEDALS: "Clipless" is a term created in response to old-fashioned toe clips. However, clipless pedals involve a cleat on the bottom of a rider's shoe that "clips in" to a spring-loaded pedal. This allows the rider to push down AND pull up on the pedals. Riders release from clipless pedals by rotating their heel to the side.
CNC: Computer Numeric Controlled: A method of computer-controlled machining that can quickly produce intricately machined parts and components. This allows small parts manufacturers to produce unique products at relatively low cost. A great boon for downhilling.
COMPRESSION: What happens when the shock absorbs impact. See Rebound.
CRANKS: The "arms" that come out from the spindle and attach to the pedals. The "drive side" crank includes the chain rings.
DAMPING: Controlling the speed that a shock rebounds.
DATA ACQUISITION SYSTEM: This "black box" bike mounted computerized system records data received from sensors positioned on the bicycle. The data recorded determines proper suspension and brake tuning, via a data download.
DISC BRAKE: Modeled after motorcycle brakes. Brake pads squeeze down on a disc that is mounted to one side of the front and back wheels of the bike. Greater braking power than traditional cantilever brakes. Most popular braking system for downhillers.
DOWNHILL RIM: Downhill racing specific rim. The rim is no less than two inches in width, has a heavy construction, and does not have a braking surface (due to disck brake).
DOWN TUBE: The tube that goes from the fork to the crank.
DRIVETRAIN: Same as the drive train on your car. What makes the bike go: the cranks, chain rings, chain, rear cassette (cogs), and derailleurs.
DROPOUT: The part of the frame and fork that the wheels are bolted into.
DRUM BRAKE: Modeled after car brakes. Brake pads push out against the drum, which is mounted on one side of the front and back wheels. Greater braking power than traditional cantilever brakes and disc brakes, but heavier and more complex. Very effective braking system, but not as popular as the others due to complexity and expense. Heavier than any other braking system. Mainly popular among downhillers.
ELASTOMER: A type of "spring" used in suspension systems, usually molded rubber or polyurethane.
FORK CROWN: The part of the fork that connects the steer tube to the fork blades. On suspension forks, the crown can often be changed to accommodate different size steer tubes. Downhill bikes often have more than one "crown" (double and triple clamp designs), in order to make the front end of the bike stiffer.
FULL-SUSPENSION: A bike that is suspended front and rear. Front and rear shock absorption.
GRIP SHIFT: The popular twist-grip gear shifting system.
HARDTAIL: A style of mountain bike that combines a rigid frame with front suspension.
HEAD ANGLE: The angle at which the head tube is set relative to the ground. Steeper head angles are generally quicker-handling, whereas shallower angles are slower-handling.
HEAD TUBE: The tube that houses the headset.
HEADSET: The bearings and cups that hold the fork in the frame. This allows you to steer.
HYSTERESIS: The friction that slows rebound on elastomer-based suspension systems.
KNOBBIES: Tires with high-profile treads, as found on most off-road specific tires.
LEATHERS: Race suits popular with most downhillers. A term made popular by motorcycle racers. The old style suits were actually made of leather creating a second skin. The new leathers, more motocross specific, are made of comfortable materials designed to protect and breathe.
LONG TRAVEL: Refers to the shock or suspension travel length. Front or rear suspension that is over six inches in travel length can be referred to as long travel.
MANITOU: A popular brand of suspension forks.
MUD TIRES: Double wide tires used for riding in mud, sand, and snow conditions. Wider tires allow a rider to run lower tire pressure, thus providing more surface area and higher traction. Becoming popular for use in downhilling.
PLATFORM PEDALS: The pedals you grew up with. No clipless system and no toe clips. Used especially in Dual Slalom racing.
PROGRESSIVE SPRING: Suspension systems that get stiffer as travel increases.
QUICK-RELEASE: A cam device that allows a rider to adjust saddle height or remove wheels by flipping a "quick-release" lever.
RAPIDFIRE: Shimano trigger-style shifter levers.
REBOUND: When a shock and wheel return to their original position after compression.
RIGID: A style of bike that uses no suspension systems. The original mountain bikes were of the rigid variety. Probably no downhill racers will be using rigid bikes.
SEALED BEARING: A bearing system that uses a physical seal to keep out water and debris.
SEAT ANGLE: The angle formed between the seat tube and the ground. Steeper angles are better for sprinting and out of the saddle climbing, whereas slack seat angles are better for high speed downhill riding, thus creating more predictable handling characteristics.
SEAT POST: Post that the seat is attached to, to be inserted into the seat tube.
SEATSTAY: The tubes that connect the rear dropouts to the seat tube.
SEAT TUBE: Bicycle frame tube that is the center of construction. The tube into which that the seat post is inserted.
SEMI-SLICKS: Tires with low-profile tread. In between slicks and knobbies.
SHORT TRAVEL: Refers to the shock or suspension travel length. Front or rear suspension that is under six inches in travel length can be referred to as short travel.
SLICKS: Tires with no tread. Great for training or road riding.
SLIDER: The part of a suspension fork that moves during compression.
SPRING: A material or materials used to absorb shock. Air, elastomers and metal springs are commonly used as springs in suspension systems.
STANCHION: The upper tube on a suspension fork. Larger stanchion tubes are generally stronger and more rigid laterally.
STEERER TUBE: The tube that connects the fork to the handlebar stem.
STICTION: Short for static friction. The friction felt when a shock compresses and rebounds.
STRAIGHT GAUGE: Items that don't change in diameter or thickness. Straight-gauge tubes and spokes are often used for increased strength or to reduce cost.
STUDDED TIRES: Just like a studded snow tire for your car, i.e. metal studs sticking up through the rubber.
SUSPENSION HUB: A hub whose axle or body diameter has been increased. These hubs' increased size improves rigidity on suspension forks and frames.
TITANIUM: The fourth most common metal in the world. Strong and light, titanium is used for everything from frames to spokes. The drawback is that it's expensive and difficult to work with. Not great for downhilling.
TOP TUBE: The tube that connects the head tube to the seat tube. Most mountain bikes feature sloping top tubes for more stand-over clearance.
TRAVEL: The distance the shock or wheel moves during compression.
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