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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
| Aheadset | The trade name of a newer design of heaset, which uses an unthreaded steered tube. The stem clamps on externally (see expander wedge). |
| Allen Key | Hexagonal wrench, available in various sizes, that fit into the head of an Allen Bolt. Most bikes use Allen Bolts |
| Anodising | Treatment proces that colors of hardens the surface of aluminum. |
| Back-cut | The vertical part of the bench cut that's blended into the backslope |
| Backslope | Slope on the uphill side of the trail. This should be a gradual change from the tread, slowing runoff by preventing a waterfall effect. |
| Bar Ends | Bolt-on extensions to your handlebars, that give you extra, more powerful positions to climb or cruise with. |
| Bearings | The round balls that rotate on bearing surfaces inside your hubs and bottom brackets. |
| Bench cut | A semi-flat trail tread created by digging down to mineral soil in the hillside. Care must be taken to preserve some outslope while making a ridable and walkable path. |
| Berm | The ridge that develops along the downhill edge of a trail. It's caused by tread compaction and soil displacement during trail use. A berm traps water on the trail. |
| Bolt Circle Diameter (BCD) | The diameter of the circle drawn through the center of the chainring bolts. Improtant to know when ordering replacements. |
| Boss | A frame fitting that's welded directly to the frame tubes. |
| Bottom Bracket | The bearing that the cranks spin on, held in the bottom bracket shell. |
| Bridge | Allows trail users to pass over ravines, bogs, creeks, rivers and similar obstacles. |
| Bunny Hop | Lifting the bike clear off the ground by pulling up on the bars and pedals. |
| Butting | A metal component that has the wall thickness or section increased in a step that is said to be butted. |
| Cadence | The rate (in rev/sec)that you pedal at |
| Cantilivers | The brakes that are typically fitted to all mountain bikes. They run on pivots welded to the forks or rear stays. |
| Cartridge Bearings | A sealed bearing unit that pops into a shell, containing the bearing surfaces, ball bearings, grease and dirt seals. |
| Chain Suck | When the chain ring refuses to let go of the chain, the chain gets sucked between the chainset and chainstay, usually causing damage. |
| Chainrings | The cogs (usually 3) fitted to the crankset. They increase in size from the inner to outer. |
| Chainstays | The frame tubes that run from the bottom bracket shell to the rear dropout. |
| Chromoly | A high strength steel alloy used in bicycle frame construction |
| Cleat | A hardened metal plate that clips into a clipless pedal's mechanism, locking the shoe to it. |
| Climbing turn | A turn that transitions from one leg to the next as the trail ascends (or descends) a hill. |
| Clinometer | Instrument used to measure the slope of ground. Also known as an inclinometer or clino. |
| Cogs | The cogs are at the rear of the bike and driven by the chain |
| Contour trail | Pathway that gently traverses a hill or sideslope, following natural contour lines as illustrated by a topo map. Allows water to sheet across the trail, thus minimizing impact to the tread. |
| Control points | Places of interest that trail users will be attracted to (desirable) or should avoid (inappropriate). Mark control points and use them to determine the placement of a new trail. |
| Crank | The metal arms that run from the pedal to the bottom bracket axle. |
| Crank Extractor | Specialist tool for removing crank arms. |
| Crib wall | A retaining wall that raises the trail significantly. Often used to stabilize the trail tread and prevent it from collapsing down the fall line. Can be built with rock or wood. |
| Damping | A speed sensitive system which uses oil to control the movement of a suspension system |
| De-berming | Removing the berm, or ridge of dirt that forms along a trail's downhill edge. Restores the tread's outslope, allowing water to sheet off. (See "outslope" and "berm.") Directional use trail - A trail intended for travel in one direction |
| Derailleur | The mechanism that pushes the chain across the cogs or chainwheels, when a shift lever is moved |
| Directional use trail | A trail intended for travel in one direction only. May be reversed periodically. |
| Disc Brake | A braking system that works on a disc mounted to the hub, rather than working on the rim. |
| Dish | The amount a wheel is offset on the hub. A rear wheel is dished to give room for the cogs. |
| Double Butted | A tube that has greater wall thickness at both ends than in the middle section |
| Down Tube | The frame tube that runs from the bottom of the head tube to the bottom bracket |
| Drainage | Removal of water from the trail |
| Dropout | The plate welded to the frame or forks, where the wheels locate into the frame |
| Elastomers | Synthetic rubbers that have elastic properties. Used in suspension forks as a spring and damping medium |
| Endo | The maneuver of flying over the handlebars, thus being forcibly ejected from the bike (Short for End over End) |
| Erosion | The natural process of wearing down and moving rock and soil by wind and water. Trail erosion can be accelerated by a combination of users, water and gravity. |
| Expander Wedge | Used to jam the traditional stem inside the steerer tube of the for (see Aheadset) |
| Fall line | Direction that water flows down a hill. The path of least resistance. |
| Fillslope | The portion of a trail that's constructed from excavated material. Fillslope can be unstable so should not be used to build trail tread. Full bench construction is preferred. |
| Flange | The part of the hub the spokes thread through |
| Flow | The rhythm or "feel" of a trail. Two basic types include "open and flowing" and "tight and technical." |
| Forks | The part of the bike that holds the front wheel, and turns to allow steering. |
| Freewheel | Cunningly designed hub that allows the wheel to keep going when you stop pedaling |
| Freewheeling | When the bike continues forward motion yet the rider is not pedaling (Same as Coasting) |
| Front Derailleur | The gear mechanism that shifts the chain across the chainwheels |
| Full bench | Tread construction method of excavating down and into the hillside. Puts the entire tread width on mineral soil, maximizing sustainability. (See "bench cut.") |
| Gear Ratio | A method of determining the gearing of the bike, measured in effective wheel diameter. |
| Grade | Trail steepness. (See "percent of grade.") |
| Grade dip | Undulation in the tread that traps water and diverts it off the trail. Makes trails more interesting and fun to use. |
| Grade reversal | Brief change in trail grade direction, such as routing a downhill section back up the hillside for a short distance. Used to divert water off the trail. |
| Granny Ring | The smallest chainring |
| Gripshift | A type of gear changing system that uses the grip as a shifter. |
| Groupset | The core of a bike’s components. Gears, brakes, hubs, bearings, cranks, and headset. |
| Half rule (50 percent rule) | If the trail grade exceeds 50 percent of the hillside slope, gravity will pull water down the trail instead of across it. This is known as "exceeding the fall of the hill." Hybrid - A trail design that blends "open and flowing" and "tight |
| Handlebar | The part of the bike that your grips, shifters, and levers mount to. Also used for steering the the bike. |
| Headset | The bearings in which the fork steerer tube rotates, contained in the heatube. |
| Hub | The unit that holds the bearings, and supports the spokes at the center of the wheel. |
| Hybrid Trail | A trail design that blends "open and flowing" and "tight and technical" features. |
| Hyperglide | Brand name of Shimano rear gear cogs which have profiled teeth and special shift ramps for easier shifting under load. |
| IMBA | International Mountain Bicycling Association, P.O. Box 7578, Boulder, CO, USA 80306; (303) 545-9011; www.imba.com. Leading resource for mountain bike-oriented trail design, construction, maintenance and management information, and mountain biking in general. |
| Indexing | Gears which click from position to position, making selecting the right one easy. |
| Jockey Wheels | The two small wheels which gude the chain in the rear derailleur. |
| Knick | Shaved-down section of trail, about 10 feet in diameter, with an exaggerated outslope. Like a rolling grade dip, a knick is used to shed water off a trail. |
| Knobbies | Aggressive tires for true off road use. |
| Lacing | The process or type of spoking pattern used on wheels. |
| Land manager | Any person responsible for decisions regarding the use of public or private lands. |
| Lube | Anything from oil to heavy duty grease. Dry lubes evaporate leaving a dry film. Wet lubes remain wet to the touch and protect better in wet conditions. Dry lubes are good for dusty conditions because they don’t pick up dirt. |
| Mineral soil | Dirt that's below the top layer of leaves, roots and other organic material. When making a bench cut, always dig down to mineral soil if possible. |
| Multiple-use trails | Those used for more than one type of activity, such as for cycling, hiking and horseback riding. |
| Nipple | Small brass or alloy threade adjuster that fixes the spokes to the rim |
| Nylock | A nut with a nylon insert which the bolt thread cuts into, designed to stop the nut from working loose |
| Open and flowing | A trail design marked by sweeping turns, higher speeds and longer sight lines. |
| Outslope | Trail tread that's canted very slightly in the same direction as the hill's slope. Allows water to sheet across rather than be trapped. |
| Percent of grade | Preferred method of measuring slope or a hill's steepness. For example, a grade of 10 percent means there is a rise or fall of 10 vertical feet per 100 linear feet. |
| Presta | The thin valve, used more commonly on racing bikes, and choice for some offroad riders. |
| Quick Release | (QR) A mechanism that allows quick and easy tightening usually of the wheel hub/axle assembly and the seatpost clamp. |
| Rapidfire | A type of shifter, made by Shimano, which operates with two levers, wither moving the cahin to a larger or smaller cogs. |
| Rear Derailleur | The gear mechanism that moves the cahin across the rear cogs |
| Re-route | A new section of trail that replaces an existing section. Re-routing is often the best remedy for a poorly designed trail that requires frequent maintenance. |
| Rim | The metal hoop of the wheel, and that the tire runs on. |
| Rolling grade dip | A non-obtrusive feature that diverts water off the trail by altering the grade. It's essentially a man-made grade reversal. |
| Saddle | The seat of the bike |
| Schrader | A type of valve used on cars and some mountain bikes. |
| Seat Post | The tube that supports the Saddle |
| Seat Stays | The frame tubes that run from where the seat post enters the frame to the rear dropouts. |
| Sheet flow | A dispersed flow of water. It minimizes erosion by preventing water from achieving high velocity and carrying away topsoil. |
| Shifters | The levers on the handle bars that allow you to change gears |
| Shimano | The Japanese component manufacturer which has almost total market dominance on production bikes. Makes good reliable equipment |
| Sill | Stone or timber supports that keep bridge stringers from contacting the ground. |
| Singletrack | A trail so narrow that users must generally travel in single file. |
| Single-use trails | Designed for only one type of user. This can be a problem if other users begin traveling the trail. |
| Slider | The moving part of a suspension fork leg |
| Slope | The natural (or man-made) pitch of the land, as shown on contour maps. Generally refers to the hill, not the trail. The trail "slope" is called "grade." |
| Social trails | Paths created by people who wander away from set trails |
| Spinning | Smooth Pedaling motion at high RPM’s |
| Spoke Key | Tool which turns spoke nipples and adjusts spoke tnsion. A wheel wrecker in the wrong hands. |
| Spokes | The thin metal cables that run from the hub to the rim |
| Stanchion | The fixed part of a suspension fork leg. |
| Steerer Tube | The tube that runs inside the head tube. Located inside the headset and supports the front fork. |
| Stem | The assembly that connects the handlebars to the Steerer Tube of the front forks |
| Stringer | A structural component of a bridge. It spans from bank to bank and supports the decking. |
| Sustainable trails | What every designer and construction crew should strive for: low-maintenance trails that have minimal impact on natural systems. |
| Switchback | A sustainable turn on a hillside. The trail is routed onto a level deck where it makes a transition to the opposite direction. |
| Texturing | Placing natural features (rocks, logs, etc.) back into the tread to increase its technical nature. Helps limit speed, and thereby reduces user conflict. |
| Tight and technical | A trail design that includes tight turns, natural technical features and mandates slower speed. |
| Tire Iron | Small plastic/vinyl tool used to remove tires during inner tube repairs |
| Top Tube | The horizontal frame tube that runs from the top of the head tube to the top of the seat tube. |
| Topographic (topo) map | Charts elevation changes and shows features such as knolls, ravines, rivers and contours. |
| Trail corridor | The area around and above the tread. Remove fast-growing impediments, but leave grasses and trees. |
| Tread creep | Describes a contour trail sagging or sliding down the hill. Causes include bushes or trees protruding into the trail from above, exposure of roots from an uphill tree, an improper bench cut or poor trail flow. |
| Truing | The process of straightening a wheel by adjusting the tension of the spokes |
| Turnpike | Trailbuilding technique that uses a combination of gravel, soil or other filler material to make the tread higher than the surrounding water table. Useful in low-lying areas with poor drainage. |
| Wang Chung | When a rider smacks their crotch against the crossbar, stem, handle bars, etc, causing a extreme pain. |
| Wheelbase | The distance between the front and rear axles |
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