Glossary
100mm Front Spacing
The standard front hub flange spacing for most non-boost bikes.
110mm Boost Front Spacing
The wider front hub spacing introduced with the Boost standard for improved wheel stiffness.
135mm Rear Spacing
The traditional rear hub spacing used on most non-boost mountain bikes.
142mm Rear Spacing
A rear hub spacing standard using a 12mm thru-axle, common before Boost.
148mm Boost Rear Spacing
The Boost rear hub spacing standard offering improved chainline and wheel stiffness.
1x Drivetrain
A drivetrain with a single front chainring and wide-range rear cassette, eliminating the front derailleur.
ABP (Active Braking Pivot)
Trek's suspension design that places the main pivot concentric with the rear axle to isolate braking forces.
Air Spring
A suspension spring that uses compressed air instead of a metal coil, allowing easy adjustment via a pump.
Anti-Rise
A suspension property describing how much braking forces affect suspension movement.
Axle Path
The arc or curve the rear axle follows as the suspension compresses and extends through its travel.
B-Tension Screw
An adjustment screw on a rear derailleur that sets the distance between the guide pulley and cassette sprockets.
Bar (Pressure)
A metric unit of pressure equivalent to approximately 14.5 PSI, used in tire and suspension pressure measurement.
Bar Sweep
The rearward angle of a handlebar from the clamp area to the grip ends, affecting wrist comfort.
Barrel Adjuster
A threaded cylindrical adjuster on a cable stop or derailleur that allows fine-tuning of cable tension.
Berm
A banked corner on a trail that allows riders to maintain speed through turns.
Bike Park
A resort or facility with purpose-built downhill trails, often with chairlift access.
Boost Spacing
A wider hub spacing standard — 110mm front, 148mm rear — allowing wider tire clearance and stiffer wheel builds.
Bottom Bracket Drop
The vertical distance the bottom bracket sits below the axle centerline, affecting cornering clearance and stability.
Bottom Bracket Drop
The vertical distance the bottom bracket sits below the wheel axle centerline.
Bottom Bracket Height
The height of the bottom bracket above the ground, affecting pedal clearance and center of gravity.
Bottom Out
When suspension reaches the end of its travel under a large impact, often felt as a harsh clunk.
Bottom Out Resistance
A feature of air springs that progressively increases resistance near the end of travel to prevent harsh bottom outs.
Brake Bed In
The process of transferring pad material to the rotor surface to achieve optimal braking performance.
Brake Contamination
Oil or other substances on brake pads or rotors that reduces braking effectiveness.
Brake Fade
A reduction in braking power caused by heat buildup in the rotors and pads during sustained braking.
Brake Lever Reach
The distance from the handlebar to the brake lever blade, adjustable on most modern levers for different hand sizes.
Brake Modulation
The ability to finely control braking force between fully released and fully applied.
Brake Rotor
The metal disc attached to the wheel hub that brake pads clamp onto to slow the bike.
BSA (British Standard) Bottom Bracket
The most common threaded bottom bracket standard, with 1.37-inch threads and 68mm or 73mm shell width.
Bunny Hop
A technique for lifting both wheels off the ground simultaneously to clear obstacles.
Cable Housing
The outer sheath that guides brake and derailleur cables, protecting them from dirt and damage.
Cable Tension
The tightness of a shift or brake cable, affecting actuation and feel.
Cadence
The rate of pedaling measured in revolutions per minute (RPM).
Casing a Jump
Landing short of a jump's intended landing zone, typically hitting the knuckle of the jump.
Cassette
A cluster of sprockets on the rear hub that provides the range of gears on a bike.
Center of Curvature
The point describing the curvature of the axle path as suspension moves through its travel.
Centerlock
Shimano's rotor mounting standard using a splined interface and lockring, offering quick and precise installation.
Chain Stretch
Wear elongation of a bicycle chain over time, causing poor shifting and accelerated sprocket wear.
Chainline
The alignment between the chainring and rear sprockets, affecting shifting performance and chain wear.
Chainstay Length
The distance from the bottom bracket to the rear axle, affecting climbing traction and maneuverability.
Cleaning a Feature
Successfully riding through a trail feature or section without putting a foot down or crashing.
Cleat
A metal or plastic fitting on the bottom of a cycling shoe that engages with a clipless pedal.
Clincher Tire
The most common tire type, with a separate inner tube and hooked bead that clinches onto the rim.
Clipless Pedals
Pedals with a binding system that clips into cleats on the bottom of cycling shoes.
Clutch Derailleur
A rear derailleur with a friction mechanism on the cage pivot to reduce chain slap and drop.
Coil Spring
A metal helical spring used in suspension forks and rear shocks, known for linear feel and low maintenance.
Compression Damping
Resistance to suspension compressing, controlling how quickly the suspension moves inward under impact.
Compressionless Housing
Brake cable housing constructed to resist lengthwise compression for more consistent brake feel.
Crank Length
The distance from the crank bolt center to the pedal axle center, affecting leverage and pedaling arc.
Cross 3 Lacing
The most common spoke lacing pattern where each spoke crosses three others between hub and rim.
Cross Chaining
Using extreme gear combinations that put the chain at a severe angle, causing accelerated wear and noise.
Cross Country Racing
A racing format involving laps on mixed terrain emphasizing fitness, climbing, and technical skill.
Derailleur Hanger
A replaceable aluminum tab on the frame that the rear derailleur bolts to, designed to break before the frame.
DOT Fluid
Glycol-based hydraulic brake fluid used by SRAM, Formula, and others. Hygroscopic — absorbs moisture over time.
Doubletrack
A wider trail or dirt road with two wheel ruts, often an old fire road or jeep track.
Downhill Racing
Racing format where riders descend a steep course as fast as possible, typically using chairlifts for uplift.
Drop
A feature where the trail ends abruptly and the rider becomes airborne before landing on a lower surface.
Dropper Post
A seatpost with a remote-actuated mechanism allowing the rider to raise and lower seat height on the fly.
Dual Compound Tire
A tire with a harder center tread for rolling efficiency and softer edge knobs for cornering grip.
Dual Ply Tire
A tire with two layers of casing fabric for increased puncture and sidewall protection, common in DH racing.
DW-Link
Dave Weagle's co-rotating twin-link suspension design used by Pivot, Evil, and others.
Effective Seat Angle
The actual angle from bottom bracket to saddle position, accounting for setback.
Effective Top Tube
The horizontal distance from the head tube to the seat tube, used to compare frame sizes across different designs.
Endo
A crash or maneuver where the rider goes over the handlebars, also called a front flip.
Enduro Racing
A format where timed stages are ridden downhill and untimed transfers are pedaled between stages.
File Tread
A tire tread pattern with small closely-spaced knobs optimized for hard-packed and dry conditions.
Fixed Gear
A drivetrain with no freewheel mechanism — the rear cog is directly connected to the rear wheel so pedaling is always required.
Flat Pedals
Simple platform pedals with pins for grip, used without special shoes.
Flip Chip
A small reversible hardware insert in a suspension link that allows geometry adjustments like BB height and head angle.
Float
The rotational movement allowed by a clipless pedal before the cleat releases, reducing knee stress.
Flow Trail
A purpose-built trail with smooth berms, rollers, and jumps designed for momentum and fun.
Folding Tire
A tire with a Kevlar bead instead of wire, allowing it to be folded for storage and reducing weight.
Fork Offset
The perpendicular distance between the fork's steering axis and the front axle centerline.
Freehub
The ratcheting mechanism on the rear hub that the cassette mounts onto, allowing coasting.
Freehub Body
The splined outer shell of the freehub that the cassette slides onto.
Freewheel
An older rear sprocket cluster that includes its own ratcheting mechanism, threading directly onto the hub.
Front Center
The distance from the bottom bracket to the front axle.
Gap Jump
A jump with open space between the takeoff and landing, requiring commitment to clear safely.
Gear Ratio
The mathematical relationship between chainring teeth and rear cog teeth, determining pedaling effort and speed.
GPS Computer
A handlebar-mounted device that tracks speed, distance, elevation, and route using GPS satellites.
Grips
Rubber or foam coverings on the handlebar ends that provide comfort and control.
Handlebar Rise
The height difference between the bar clamp area and the ends of the handlebar.
Handlebar Width
The total width of the handlebar, affecting leverage, control, and fit.
Hardpack
Firm, compacted trail surface that offers fast rolling and predictable traction.
Head Tube Angle
The angle of the head tube relative to the ground, affecting steering speed and stability.
Headset
The bearing assembly at the head tube that allows the fork to rotate for steering.
Heart Rate Monitor
A device that measures beats per minute during exercise, used to gauge exertion and fitness.
Hero Dirt
Colloquial term for perfectly conditioned soil that provides ideal traction in all conditions.
HG Freehub
Shimano's standard freehub spline pattern, compatible with most Shimano and SRAM cassettes up to 11-speed.
High Pivot
A suspension design with the main pivot placed high on the front triangle, paired with an idler pulley.
High Speed Compression
Damping that controls suspension movement during fast, sharp impacts like rocks and roots.
High Speed Rebound
Damping that controls how quickly suspension returns after a large, fast impact.
Hookless Rim
A rim without a hooked bead seat, requiring tubeless-specific tires and lower maximum pressures.
Horst Link
A four-bar suspension design with a pivot on the chainstay below the axle, used by Specialized and others.
Housing End Cap
A ferrule that fits over the end of cable housing to prevent fraying and ensure smooth cable movement.
Hub Flange
The flat circular part of a hub with holes for spoke heads.
Hub Shell
The outer body of a hub that the spokes attach to.
Hydraulic Disc Brake
A disc brake system that uses hydraulic fluid to transfer lever force to the caliper, offering powerful and consistent braking.
Idler Pulley
A small pulley used in high-pivot suspension designs to maintain chain length as the suspension moves.
Inner Wire
The cable that runs through housing to actuate brakes or derailleurs.
Instant Center
The theoretical pivot point around which a suspension system rotates at any given point in its travel.
Integrated Headset
A headset where the bearings sit directly in the head tube without cups, requiring precise frame machining.
Internal Rim Width
The measurement between the inner walls of a rim, directly affecting tire profile and volume.
Knobbly
Informal term for a mountain bike tire with pronounced tread knobs for off-road traction.
KOM (King of the Mountain)
The fastest recorded time on a Strava segment, awarded to the top male rider.
Leverage Ratio
The mechanical relationship between wheel travel and shock travel at any given point in suspension travel.
Limit Screws
Adjustment screws on a derailleur that set the maximum inward and outward travel of the derailleur cage.
Line
The chosen path through a trail feature or section.
Lined Housing
Cable housing with a low-friction inner liner to reduce cable friction and improve shifting or braking feel.
Linkage Driven
A suspension design where a linkage system drives the shock rather than connecting directly to the swingarm.
Loam
Dark, loose, organic soil that provides excellent traction and is highly sought after by mountain bikers.
Lock-On Grips
Handlebar grips that clamp onto the bar with a collar, preventing rotation without adhesive.
Lockout
A feature that firms up or completely locks suspension to reduce bob during climbing or road riding.
Low Speed Compression
Damping that controls suspension movement during slow, sustained forces like pumping and body movement.
Low Speed Rebound
Damping that controls how quickly suspension returns during slower, more controlled movements.
Manual
Riding with the front wheel lifted without pedaling, balancing on the rear wheel.
Mechanical Disc Brake
A disc brake actuated by a cable rather than hydraulic fluid, simpler but less powerful than hydraulic systems.
Microspline
Shimano's freehub standard for 12-speed cassettes with a 10-tooth smallest cog.
Mineral Oil
A non-hygroscopic hydraulic brake fluid used by Shimano and others, requiring less frequent replacement than DOT fluid.
Narrow Wide Chainring
A chainring with alternating narrow and wide teeth that mesh tightly with chain plates to prevent chain drop.
Negative Spring
A small air chamber that counteracts the positive spring at the beginning of travel to improve small-bump sensitivity.
Open Tread
A tire tread with widely spaced knobs that self-clean in mud and loose conditions.
Organic Brake Pads
Resin-compound brake pads that offer better initial bite and quieter operation but wear faster than sintered pads.
Pedal Bob
Unwanted suspension movement caused by pedaling forces, common in poorly tuned or designed suspension.
Pedal Platform
The surface area of a flat pedal that the foot rests on.
Platform Damping
A threshold of force required before suspension begins to move, reducing pedal bob without fully locking out.
Power Meter
A device that measures cycling power output in watts, used for training and performance analysis.
Preload
Initial tension applied to a spring to adjust the starting position and feel of suspension.
Press Fit Bottom Bracket
A bottom bracket that presses directly into the frame shell without threads, allowing larger bearing diameters.
Progression
The rate at which a suspension system becomes stiffer as it moves through its travel.
PSI (Pounds Per Square Inch)
A unit of pressure used to measure tire inflation and suspension air spring pressure.
Pump Track
A circuit of rollers and berms designed to be ridden without pedaling by pumping the terrain.
Q-Factor
The distance between the outer faces of the crank arms, affecting pedaling stance width.
Quick Release
A lever-operated skewer that passes through hollow axle hubs to secure wheels without tools.
Quick Release Skewer
A hollow skewer with a cam lever that clamps through a hub axle to secure the wheel.
Radial Lacing
A wheel lacing pattern where spokes go directly from hub to rim without crossing, used on low-stress front wheels.
Reach
The horizontal distance from the bottom bracket to the top of the head tube, a key sizing measurement.
Rebound
The speed at which suspension returns to its extended position after being compressed.
Rim Tape
Tape applied to the inner rim bed to seal spoke holes for tubeless setups.
Rim Width
The internal or external width of a wheel rim, affecting tire fit, shape, and performance.
Rock Garden
A trail section covered in rocks of varying sizes requiring technical line choice and bike control.
Rocker Link
A pivoting link that connects the rear triangle to the shock, used to tune leverage ratios.
Roller
A smooth rounded mound on a trail that can be pumped for speed or jumped.
Saddle Height
The distance from the center of the bottom bracket to the top of the saddle, a fundamental bike fit measurement.
Saddle Setback
The horizontal distance the saddle sits behind the bottom bracket center.
Saddle Tilt
The angle of the saddle relative to horizontal, affecting comfort and power transfer.
Sag
The amount a suspension compresses under the rider's weight when sitting in a neutral riding position.
Seat Tube Angle
The angle of the seat tube relative to the ground, affecting pedaling efficiency and weight distribution.
Seatpost Setback
The offset of a seatpost that places the saddle rails further behind the seatpost clamp center.
Send It
Colloquial term for committing fully to a jump or challenging feature.
Single Chainring
A drivetrain setup with only one chainring at the front, relying on a wide-range rear cassette for gearing.
Single Speed
A bike with only one gear ratio, using a freewheel or fixed cog with no derailleur.
Singletrack
A narrow trail wide enough for only one rider, the primary surface of mountain biking.
Sintered Brake Pads
Metal-compound brake pads that offer longer life and better wet-weather performance but require more rotor wear-in.
Six Bolt Rotor
The most common rotor mounting standard, using six small bolts to attach the rotor to the hub flange.
Slick Tire
A tire with minimal or no tread pattern, used on smooth surfaces for reduced rolling resistance.
Spoke Count
The number of spokes in a wheel, affecting weight, strength, and aerodynamics.
Spoke Lacing
The pattern in which spokes are arranged between hub and rim, affecting wheel stiffness and strength.
Spoke Nipple
A small nut that threads onto the spoke at the rim, used to adjust spoke tension.
Spoke Tension
The tightness of spokes in a wheel, critical for wheel strength, trueness, and longevity.
Spring Rate
The stiffness of a spring, measured as the force required to compress it by a given distance.
Stack
The vertical distance from the bottom bracket to the top of the head tube.
Standover Height
The height of the top tube at its midpoint, relevant for fit and clearance when stopping.
Steerer Tube
The upper portion of the fork that passes through the head tube and is clamped by the stem.
Stem Length
The distance from the steerer tube clamp center to the handlebar clamp center, affecting handling and fit.
Stem Rise
The angle of a stem relative to horizontal, affecting handlebar height.
Stiction
Static friction in suspension seals that prevents smooth small-bump response, especially when cold.
Strava
A popular GPS activity tracking app used by cyclists and runners to record rides and compare segments.
Superboost
An even wider rear hub spacing of 157mm, used on some enduro and DH bikes for additional chainline clearance.
Switch Infinity
Yeti's unique suspension design using a sliding link that changes pivot location through the travel.
Switchback
A sharp hairpin turn on a trail, often on steep terrain, requiring slow speed and precise technique.
T47 Bottom Bracket
A threaded bottom bracket standard with a larger 47mm inner diameter, combining threaded reliability with press-fit bearing sizes.
Table Top
A jump with a flat top surface between the lip and landing, safer than gaps because it can be ridden flat.
Tapered Steerer
A steerer tube that is 1.5 inches at the lower bearing and 1.125 inches at the stem clamp for increased stiffness.
Technical Trail
A trail with challenging features like rocks, roots, steep sections, and tight turns requiring skill to navigate.
Threaded Bottom Bracket
A bottom bracket that threads into the frame shell, known for ease of installation and reduced creaking.
Threaded Headset
An older headset standard where the fork steerer tube has threads for adjustment, common on older bikes.
Threadless Headset
The modern standard headset where a stem clamps onto a smooth steerer tube and a top cap adjusts bearing preload.
Thru-Axle
A solid axle that threads through the fork or frame dropout and into the hub, replacing quick release skewers.
Tire Bead
The edge of a tire that seats against the rim, holding the tire in place. Can be wire or folding (Kevlar).
Tire Casing
The fabric structure of a tire, rated by threads per inch (TPI). Higher TPI = lighter and more supple.
Tire Compound
The rubber formulation of a tire tread, balancing grip, durability, and rolling resistance.
Tire Insert
A foam or rubber insert inside a tubeless tire that protects the rim from impacts and prevents burping.
Tire Pressure
The amount of air in a tire measured in PSI or bar, affecting rolling resistance, traction, and puncture resistance.
Tokens
Small plastic inserts placed inside an air spring to reduce volume and increase progression.
TPI (Threads Per Inch)
A measurement of tire casing density. Higher TPI casings are lighter, more supple, and more puncture resistant.
Trail
A geometry measurement describing the horizontal distance between the front axle and the steering axis contact point.
Trail Riding
General recreational mountain biking on natural or purpose-built trails.
Travel
The total distance a suspension system can compress, measured in millimeters.
Tread Pattern
The arrangement of knobs and voids on a tire surface, designed for specific terrain and conditions.
Tubeless
A wheel and tire setup without an inner tube, using a sealed rim and tubeless-ready tire with sealant.
Tubeless Sealant
Latex-based liquid inside a tubeless tire that automatically seals small punctures.
Tubular Tire
A tire with an inner tube sewn inside the casing, glued to a special rim. Used in road racing.
Two Finger Braking
The modern technique of using only the index and middle fingers on brake levers for better control.
Uplift
Shuttle service or chairlift that carries riders and bikes to the top of a descent.
Upsweep
The upward angle of a handlebar from clamp to grip ends, affecting wrist and shoulder position.
VPP (Virtual Pivot Point)
Santa Cruz's twin-link suspension design where counter-rotating links create a virtual pivot point.
Wheel Dish
The centering of a wheel rim relative to the hub flanges, necessary for proper alignment in the frame.
Wheel True
The process of adjusting spoke tension to eliminate lateral and radial wobbles in a wheel.
Wheelbase
The distance between the front and rear axles, affecting stability and handling.
Wheelie
Riding with the front wheel lifted while pedaling to maintain the position.
Wire Bead Tire
A tire with a steel wire bead, heavier and less expensive than folding tires but not foldable.
XD Driver
SRAM's freehub standard that allows 10-tooth smallest cogs, required for Eagle 12-speed cassettes.
Zero Stack Headset
A headset design where bearing cups sit inside the head tube with only the bearing race visible.