Adventure Cycling Association

1x — Also known as “one-by,” 1x refers to a drivetrain with just one chainring, usually paired to a wide-range cassette.

Aluminum — Among the four most common materials used for bicycle frames, aluminum can make for a frame that’s lighter than steel and cheaper than carbon fiber.

Backroad — The best kind of road: has little to no traffic, passes through funky little towns, and usually offers the best views. 

Bidon — Fancy French word for water bottle. 

Bikecentennial — The nonprofit we now know as Adventure Cycling Association. Also a cross-country cycling event in 1976.

Bikepacking — Off-road bicycle touring, typically with knobby tires and soft bags. Learn more with "Getting Started with Bikepacking" and the rest of our "Bikepacking Basics" series.

Boost — Wider mountain bike hub spacing: 110mm in the front and 148mm in the rear. Don’t ask about Super Boost. 

Bottom bracket — The part of a bicycle frame where your crankset attaches. 

Braze-on — A bottle mount, rack mount, cable guide, pump peg, or other part attached to the bicycle frame via brazing, welding, gluing, or otherwise. 

Brifter — A combination shifter-brake lever, mostly found on dropbar bikes. 

Cadence — The pace at which you pedal, most often expressed in revolutions per minute (rpm). 

Carbon — A composite material made up of strands of carbon atoms bonded together into a matrix with epoxy and woven into fabric-like sheets, which are then placed into a mold. Strong, light, expensive — pick all three. 

Chamois — The squishy, diaper-like part of your cycling shorts. Not to be confused with an actual diaper. 

Chip seal — The single most hated form of road sealing. It results in a rough, energy-sapping surface.

Chromoly — A steel alloy made with the elements chromium and molybdenum. 

Clipless — Also known as “clip-in” pedals, clipless pedals are used with cycling shoes that have specific cleats bolted to the underside that lock into the pedal. They allow for better power transfer and sometimes make you fall over at intersections. 

Derailer — The dangly thing on the back of your bike that moves the chain up and down the cassette. 

Double — Also known as 2x, a double drivetrain has two chainrings. 

Doubletrack — Like singletrack, but doubled. 

Dynamo — Like the alternator in your car, a dynamo hub produces electricity as it spins to power a light, a battery charger, or a George Foreman grill. 

eBike — A bicycle with an electric motor.

Frameset — A bicycle frame and fork. 

Freewheel — The part of the rear hub that allows the bike to coast when you stop pedaling, using some kind of ratchet or clutch mechanism. 

Full suspension — A mountain bike with suspension front and rear.  

Gear inch — The distance traveled with one complete revolution of the cranks in a given gear when multiplied by "pi." This measurement takes into consideration wheel and tire size as well as chainring and cog tooth counts.

Gearbox — Several planetary gears housed in a single, sealed unit, much like an automotive transmission, and usually mounted at the bottom bracket.

Geometry — The various measurements that make up a given bicycle, such as head tube angle, chainstay length, and bottom bracket drop. 

GPS — Global Positioning System, a satellite-based radionavigation system.

Gravel — The Next Big Thing in the bike industry, gravel bikes are essentially endurance road bikes with room for big tires. Learn more in "The Basics of Gravel Riding."

Hardtail — A mountain bike with front suspension only. 

Headset — The bearings in the head tube of a bicycle frame in which the fork rotates.

Headwind — See: Kansas

Hemistour — The Alaska–Argentina bicycle expedition created by Bikecentennial cofounders June and Greg Siple and Lys and Dan Burden. Started in 1972 and completed in 1975.

Hike-a-bike — Carrying, pushing, or dragging your bike up a hill, usually while shouting expletives. 

Internal geared hub — A collection of gears housed in a sealed rear hub, such as the Rohloff or Shimano Alfine. 

Kit — Bicycling attire in British English. 

MIPS — Multi-Directional Impact Protection System, a helmet technology intended to reduce brain injury from rotational impacts. 

Offset — Fork offset (also known as fork rake) is the perpendicular distance from the steering axis to the center of the front wheel. 

Pannier — A bag that attaches to a bicycle rack. Usually found in pairs. 

Plus — Extra-large mountain bike tires, 2.8in. to 3.25in. wide. 

Press-fit — A bottom bracket design in which the bearing assembly is pressed, rather than threaded, into the frame.

Q-Factor — The distance between a bicycle’s crank arms. Also known as “tread.”

Quick-release — A cam-operated closing mechanism found in hub skewers and seatpost clamps that is hand-operated without the use of tools.

Rail trail — A paved, dirt, or gravel trail built on a disused railroad grade.

Reach — The horizontal measurement from the center of the bottom bracket forward to where the stem attaches to the steerer tube. See also: Stack

Recumbent — A bicycle (or tricycle; see: Tadpole) that puts the rider in a reclined position. 

Rigid — A mountain bike with no suspension. 

Sealant — A liquid (usually latex-based) used in tubeless tire and rim systems to seal punctures. 

Setback — The horizontal distance from the seatpost clamp to the seat tube axis. 

Sheldon Brown — He knew everything there is to know about bicycles and wrote the “Mechanical Advantage” column for Adventure Cyclist from 1997 until his untimely death in 2008. His website (sheldonbrown.com) is still the best place to go for technical bicycle questions. 

Singlespeed — A bicycle with only one gear, usually either too high or too low. 

Singletrack — A narrow, twisty dirt trail. 

Stack — The vertical measurement from the center of the bottom bracket to the where the stem attaches to the steerer tube. See also: Reach

Standover — The vertical distance from the top tube (usually just in front of the saddle) to the ground. 

Steel — An iron alloy, of which several types are used to make bicycle frame tubes. See: Chromoly

Tadpole — A recumbent trike with two wheels in front and one in the rear. 

Tailwind — What cyclists pray for most. 

Tandem — A bicycle built for two. 

Thru-axle — Originally developed for mountain bikes but increasingly found in gravel and road bikes, thru-axles attach a wheel hub to the frame or fork by threading into it. 

Titanium — Like carbon fiber, titanium is considered a wonder material for bicycles, with a price tag to back it up. 

TPI — Threads per inch, a measurement of a bicycle tire’s suppleness. Like sheets, more threads are softer.

Trail — The horizontal measurement of the distance between where the front tire makes contact with the ground and where an imaginary line along the steering axis would meet the ground.

Triple — A crank with three chainrings. 

Tubeless — A bicycle tire and rim system that forgoes inner tubes in favor of liquid sealant. 

Warmshowers — A nonprofit organization that connects bicycle travelers to hosts. Learn more from "Cycling and Warmshowers."