Home » Bike Maintenance » Glossary: the language of bikes – page 3

Glossary: the language of bikes – page 3

  • Pivot: (1) This bearing on a suspension frame allows one part of the frame to move against another; (2) this is also a rod or a bearing around which part of a component rotates.
  • Post mount: Brake callipers are mounted with bolts that point along the frame, rather than across. These are less common than the alternative, the International Standard mount, but easier to adjust.
  • Preload: This initial adjustment made to suspension springs to tune forks or shock to your weight is usually made by tweaking the preload adjustment knob, or by adding or removing air from air springs.
  • Presta valve: Also known as high pressure valves, these are more reliable than Schraeder valves, which are designed for lower pressure car and motorbike tyres. Their only disadvantage is that they cannot be inflated on gas-station forecourts.
  • Puncture-resistant tyres: These contain a strip of tough, pliable material under the tyre tread, preventing almost all of the glass and shards on the road from getting through to your tube.
  • Rapid-rise (low-normal): In this rear derailleur, the cable pulls the chain from larger to smaller sprockets, then, when cable tension is released, the spring pulls the chain back from smaller to larger sprocket.
  • Rear derailleur: This mechanism is attached to the frame on the right-hand side of the rear wheel. It moves the chain from one sprocket to the next, changing the gear ratio, when you move the shifter on your handlebars. It makes odd grinding noises when not adjusted properly.
  • Rebound damping: Rebound damping controls the speed at which the fork or shock re-extends after being compressed.
  • Reservoir: This reserve pool of hydraulic damping fluid is housed in a chamber at the brake lever. Having this reservoir of cool fluid a distance away from the hot rotor and calliper helps to minimize fluid expansion under heavy braking.
  • Reverse thread: The spiral of the thread runs the opposite way to normal: clockwise for undoing; anticlockwise for tightening.
  • Rotor: Bolted to the hub, this is the braking surface of a disc brake.
  • Sag: This is the amount of travel you use sitting normally on your bike. Setting up suspension with sag gives a reserve of travel above the neutral position.
  • S chraeder valve: This is a fat, car-type valve. The inventor, Franz Schraeder, is buried in a magical spot at the Cirque de Gavarne in the French Pyrenees.
  • S eal: A seal prevents dirt, mud and dust from creeping into the parts of hubs, suspension units, headsets, bottom brackets and any other components where the preferred lubricant is grease rather than mud.
  • Seatpost clamp: These plates and bolts connect the seatpost firmly to your saddle.
  • Seatstays: A part of your frame, these connect the middle of your back wheel to the junction where your seatpost is attached.
  • Shim: This thin piece of metal is used to make two parts fit together precisely. The washers between IS (International Standard) callipers and the frame are shims because they hold the calliper precisely in position.
  • Shimano joining pin: Once split, Shimano chains must only be joined with the correct joining pin. Attempting to rejoin the chain using the original rivet will damage the chain plates.
  • Singlespeed (1×1): This state of peace is obtained through selfliberation from the complexities of modern life by throwing away your gears.
  • Snakebite flat: See pinch puncture.
  • Socket: Shaped like a cup, this spanner holds the bolt securely on all the flats.
  • Splines: These ridges across a tool or component are designed to mesh with a matching part so that the two parts turn together.
  • Split link: This chain link can be split and rejoined by hand without damaging the adjacent links.
  • Sprocket: This toothed ring meshes with the chain to rotate the rear wheel. The cassette consists of a row of differentsized sprockets.
  • Stanchions: This upper part of the suspension forks slides into the lower legs and contains all the suspension extras, including springs, damping rods and oil.
  • Standard tube: For those who don‘t need tubelessness, this normal inner tube is designed to fit into a normal tyre.
  • Star-fanged nut (star nut, star-fangled nut): This nut is pressed into the top of the steerer tube. The top cap bolt threads into it, pushing down on the stem and pulling up on the steerer tube.
  • Stationary pad: In disc brakes with one piston, the piston pushes a pad against the rotor, which in turn pushes the rotor against the stationary pad, trapping the rotor between moving and stationary pads.
  • Steerer tube: This single tube extends from the top of the forks through the frame and has the stem bolted on the top.
  • Stem: The component that connects your handlebar to the top of your forks.
  • STi: A combined brake-lever and gear-shifter.
  • Stiff link: The plates of the chain are squashed too closely together to pass smoothly over the sprockets, and they jump across teeth rather than mesh with the valleys between teeth.
  • Straddle wire: This connects the two units of a cantilever brake via a straddle hanger on the brake cable.
  • Stress relief: You can achieve this by squeezing the spokes to settle them into place as you build a wheel.
  • Swingarm: This is the rear of a suspension frame, to which the back wheel attaches.
  • Tension jockey: The lower of the two jockey wheels on the rear derailleur is sprung so it constantly pushes backwards, taking up slack in the chain created by the different teeth size combinations of sprockets and chainrings.
  • Toe-clips: These survive today only in ghost form as the clip in clipless pedals. An unfortunate loss is the accompanying toe-strap, which was occasionally a priceless emergency item. (See ziptie.)
  • Toe-in: To prevent squeaking, rim brakes are set up so the front of the brake block touches momentarily earlier than the back.
  • Top cap: This disc, on the top of your stem, is bolted into the starfanged nut in the steerer tube. Provided the stem bolts are loose, adjusting the top cap pushes the stem down the steerer tube, tightening the headset bearings. Always retighten the stem afterward!
  • Trailerbike: These have a single wheel and clamp to the back of an ordinary bike, turning it into a mini-tandem. The trailerbike part has its own pedals and sometimes gears, too.
  • Travel: Travel is the total amount of movement in the fork or shock. The longer the travel, the heavier and beefier the fork or shock must be.
  • Triggershifters: This gear shifter features a pair of levers: one pulling, the other releasing, the cable.
  • Truing wheels: The process of adjusting the tension in each spoke prevents the rim from wobbling from side to side when the wheel spins.
  • Tubeless: In this weight-saving tyre design, the bead of the tyre locks into the rim, creating an airtight seal that needs no inner tube.
  • Twistshifters: These gear shifters work by twisting the handlebar grip. Turning one way pulls through cable, while turning the other way releases cable.
  • Tyre boot: Stuck onto the inside of a tyre, this patch prevents the inner tube from bulging out of big gashes.
  • URT: Unified Rear Triangle. In this suspension frame design, bottom bracket, chainset and front derailleur are located together on the swingarm (rear end of the bike), so the movement of the swingarm never affects the length of the chain.
  • UST: Universal Standard for Tubeless. This is an agreed standard for the exact shape of rims and tyre beads. UST tyres and rims made by different manufacturers lock together neatly for an airtight seal.
  • V-brake: In these rim brakes, two vertical (hence ‘V‘) units connected by the brake cable, hold the blocks.
  • Virtual pivot: In suspension, this is when the swingarm is made of a series of linkages that combine to rotate around a position. Rather than a physical location on the frame, this position may be a point around which the frame would rotate if it was a simple swingarm.
  • Wheel jig: This frame for holding a wheel during truing has adjustable indicators that can be set close to the rim to allow you to estimate how round and straight the rim is.
  • Ziptie: The tool for whenever you need to connect one thing to another thing.

Source : BIKE MAINTENANCE TIPS, TRICKS & TECHNIQUES

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