As time went on, the Bicycle Glossary has grown, and many of the pages became inconveniently large.
I have split the larger pages into smaller ones, but I realize that there may be external links pointing to the older pages. For this reason, I have maintained copies of the older pages at the same location.
This is one of the older pages, and the newer pages that were derived from it are liable to be more complete and up to date, so please follow the links below to the current version. Sorry for any inconvenience.
If one of my own pages had a link that took you to this page, it would be helpful if you would send me an email with the URL of the page that had the bad link, so I can update it.
Sheldon Brown
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- Highly regarded French maker of bicycle parts. Best known for their crank sets. T.A. was the pioneer in triple chainwheel crank sets. T.A. also makes bottle cages and special orthopedic pedals for cyclists with legs of different lengths.
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- A tricycle with two wheels in front, one behind.
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- A bicycle or other vehicle which accommodates two or more riders, one in front of the other. Tandems for three riders are called "triplets", for four: "quadruplets" or "quads", etc.
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- A tap is a tool for cutting female threads. It takes the form of a bolt with flutes cut in the threads, and usually has a taper at the end that is intended to start the thread. There are only a few standard sizes used on bicycles:
The corresponding nut-like tool for cutting male threads is called a die.
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- A series of handlebar stems made by Nitto. Technomic stems are very high-quality aluminum stems, in the traditional "7" shape popular for road bicycles. The special feature of the Technomic stem is that the vertical part of the stem is taller than usual. This is a great aid for fitting bicycles to riders who need a higher handlebar position than would otherwise be possible with a particular frame.
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- An instrument for measuring spoke tension.
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- The lower pulley on a rear derailer. So called because its main function is to adjust the tension on the chain as different-sized sprockets are selected.
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- A line of bicycles designed specifically to meet the fitting needs of smaller women.
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- For normal, generic nuts and bolts, there are two threading systems in common use, S.A.E. (U.S.Standard) and Metric (I.S.O.). S.A.E. threads are designated by a diameter and a number of threads per inch (TPI). For example, the common 1/4 - 20 means a bolt 1/4 inch in diameter, with 20 threads per inch. Metric bolts are sized by the diameter and the distance between adjacent threads, for example 6 x 1 refers to a bolt 6 mm in diameter with threads 1mm apart. (This is the size used for brake mounting bolts and brake shoe hardware.) Similarly, 5 x .8 means a bolt 5 mm in diameter, with threads .8 mm apart. (This size is used for fender and bottle-cage fittings, shift lever bosses, and most cable anchor bolts.) A third system, known as Whitworth, was used in Britain up until the 1960's when they converted to metric.
Bicycle parts come in even more different thread systems than common nuts and bolts. There are different standards for headsets and bottom brackets for American/BMX/OPC, British, French, Italian, Raleigh and Swiss bicycles.
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- Tungsten Inert Gas welding. A form of welding by the use of an electric arc. The area being heated is bathed in an inert gas (argon?) to prevent oxidation.
T.I.G. welding is commonly used to build lugless bicycle frames. Most current bicycle frame production is done by T.I.G. welding.
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- Most bicycle crank sets are of the three-piece type, the three pieces being the left crank, the axle, and the right crank with chainwheel(s). Three piece crank sets either use cotters or tapered cotterless attachment. There are also two-piece crank sets and one-piece crank sets.
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- Threads Per Inch, the pitch of a threaded fastener.
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- see Synch chain.
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- A race in which competitors start one-at-a-time, usually at 30 second or one-minute intervals. The winner is the cyclist who completes the course in the shortest time. Since drafting is not allowed in an individual time trial, there are no team tactics; it is just the cyclist agians the clock, hence the sobriquet "the race of truth."
The cycling leg of a triathlon is a form of time trial.
There are also team time trials, usually involving teams of 4 or more, taking turns leading and drafting each other. Team time trials require great precision in rotating position within the team.
Time trials are held both on the road and on the track.
Bicycles made for time-trial use are designed to be as aerodynamic as possible, even at the expense of degrading handling characteristics and rider comfort. Since riders are on their own, there is no need for fancy maneuvering as there is in a peloton.
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- People usually think that tires are made of rubber. This is understandable, because rubber is all that you can see.
A tire is actually made up of three parts:
- The beads
are two hoops of strong steel wire (or, sometimes Kevlar ®.)
- The cords
, cloth forming the body of the tire, woven between the two beads. Most modern tires use nylon cords.
- The rubber
, which covers all the other parts. The rubber on the part that contacts the road is thicker, and is called the tread.
A bicycle tire is not airtight by itself, so it uses an inner tube, which is basically a doughnut-shaped rubber balloon. The inner tube has a valve to allow you to blow it up.
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- A frame/fork mounted device designed to brush sharp debris from the tread of tires before it can penetrate through to the inner tube. Tire savers usually attach to the brake center bolt, and are commonly made from recycled spokes.
Toe In
- When a brake shoe hits a moving rim, the pull of the rim causes the brake arm to flex a bit. If your brake shoes hit a stationary rim perfectly straight and squarely, the flex of the brake arm will cause the rear edge of the brake shoe to do the brunt of the work. The front edge of the shoe may not even be engaging the rim under hard braking.
Good practice in installing brake shoes is to "toe them in", so that the front part of the shoe hits the rim first. As the brake arm flexes under real braking, it will permit the whole surface of the brake shoe to engage the rim.
Toeing in of brake shoes can also reduce the annoying squeal some brakes make when in use.
Most newer brake shoes have special washers with curved surfaces to allow you to adjust the angle of the shoe to the rim. Older brakes relied on brute force, typically bending the brake arm with an adjustable wrench.
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- (of drop bars)******
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- A style of front derailer operated by a cable coming down from above, as opposed to a traditional "bottom-pull" unit, operated by a cable coming up from below. Top pull derailers are mainly used on mountain bikes, because they permit the designer to avoid running the gear cables by the bottom bracket, where they are exposed to spray from the front wheel.
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- The frame tube that runs horizontally from the top of the head tube to the seat cluster. Up until the 1980's, most high quality bicycles were built with the top tube exactly horizontal. Newer frame designs commonly have sloping top tubes, higher at the front. This is particularly common in smaller frame sizes.
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- A force applied in the form of a twist, rather than a straight push or pull. "Torsion" is used to indicate that the force involved it a rotary force. "Torque" is a measurement of torsional force.
Torque is the linear force times the radius at which it is applied. For example, a 10 pound force applied two feet from the axis produces the same torque as a 2 pound force applied ten feet from the axis.
A "torque wrench" is a type of wrench with a built-in spring-loaded indicator that gives a numerical readout of the amount of torque being applied through it.
The standard units for measuring torque are pound-feet or Newton-meters. Note that the force unit goes first, so as not to be confused with power measurements. A common error is to refer to "foot-pounds" instead of pound-feet of torque. This is not strictly correct, since the foot-pound is a unit of power, not torque.
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- "Touring" is a slippery word, and means different things to different people. This can cause mis-communication, so the word should be used with caution.
To non-cyclists, or casual cyclists, "touring" may mean riding 8 miles on a rented cruiser at a beach resort, or a fund-raising "thon" ride, or any type of riding where the principal objective is leisurely enjoyment of scenery and fresh air.
In the sense more generally accepted in cycling circles, however, a "tour" is a multi-day ride, which is not a competition or a timed event.
See also touring bicycle.
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- A type of under-the-saddle bag popular in the British Isles. They attach to special loops at the rear of the saddle, and also have a strap which wraps around the seatpost.
Traditional British touring bags are roughly cylindrical (oriented crossways-no attempt is mad to make them aerodynamic). They come in a range of sizes, usually with a large main compartment and a small pocket at each end. They also feature metal rings on top of the flap to which the rider can strap a rolled-up rain cape, in case the rain stops.
Major brands are Brooks, Carradice, and Karrimor. The better quality bags are made of heavy black canvas, with grey "chrome" leather straps and corner re-inforcements.
This type of bag is not ideal for cyclists who like to stand up and thrash their bicycle from side to side while climbing, because they sway back-and-forth under this type of treatment. For the cyclist with a smooth riding style, they offer a good option for carrying a sizeable load on a bicycle which lacks pannier racks.
This type of bag is currently enjoying a resurgence of popularity.
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A touring bicycle is designed for comfort, durability, efficiency and, in most cases, load-carrying capacity. Touring bicycles fall into two major groupings:
- Loaded-touring bicycles, the classic "touring" bicycle is intended for self-supported travel, including camping and, in some cases, cooking equipment. A loaded-touring bicycle has:
A well-equipped loaded-touring bicycle will usually have:
- Drop handlebars
- Full fenders.
- Front pannier rack (usually low-rider style.)
- Rear pannier rack.
- Lighting system (usually generator-powered.)
- 3 or 4 bottle cages, for water and cooking fuel.
Increasingly, loaded touring is being done on modified mountain bikes, which share many characteristics with loaded tourers.
- Light-touring, or "credit-card" touring bicycles are intended for inn-to-inn tours, randonnés, or organized tours with sag-wagon service, in which the rider will carry perhaps a large touring bag or handlebar bag. A light-touring bicycle may be a modified road-racing bicycle, or a bicycle made for the purpose. It will usually have:
- Conservative road-racing geometry.
- A triple chainwheel crankset.
- A close- or medium-ratio cluster.
- Medium (25-28 mm) width tires.
- Clip-on aerobars.
- Clipless pedals.
- "Sport-touring" bicycles are not, strictly speaking, touring bicycles at all. This is a term normally used to refer to the general-purpose "ten-speeds" (later 12-speeds) of the '70's and early '80's. These bikes were marketed as general purpose machines, and millions were sold. Millions of them are now rusting away in the back of the garages of middle America. These bicycles are characterized by:
- 630 mm (27 inch) wheels.
- Drop handlebars
- Double chainwheels, usually 52/42 or 52/39.
- 5 speed freewheels, usually 14-28 teeth.
Since these bicycles were most often sold to people for whom drop handlebars were unsuited, many of them added features to try to make the bicycle more appealing to the casual cyclist, without losing the "racer" look:
Note: the term "sport touring" is sometimes used to refer to a "light-touring" bike by cyclists too young to remember the 10-speed era.
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- See Shimano Models
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- An oval track, also known as a "velodrome" for bicycle racing. Track bicycles have steep angles, fixed gears, and no brakes. Common track events include match sprints, pursuits, motor-paced events and miss-and-out races.
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- British term for fingerless cycling gloves.
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- An axle nut with a built-in washer loosely rivetted to it. The washer is permanently attached, but can rotate with respect to the nut. Used on high quality solid-axle hubs. Cheaper solid-axle hubs use serrated flange nuts, or plain nuts with serrated washers.
| Track Nuts | | Serrated Flange Nuts
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- The act of balancing motionless on a bicycle. This is done most easily on a fixed-gear bicycle. The rider turns the front wheel to about a 45 degree angle and balances with the cranks horizontal. If the bicycle starts to lean in the direction the front wheel faces, a slight forward movement of the cranks will bring the tires back under the rider's center of gravity. If the bicycle leans the other way, rolling backward will correct the lean.
It is possible to do a track stand on a freewheel-equipped bicycle it the front wheel is pointed up a sloping section of road.
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- The frictional force that keeps a tire from skidding. A tire with good traction will be less likely to skid.
The traction of a tire is affected by:
- The composition of the rubber of the tire
Softer rubber gives better traction, but wears out sooner.
- The nature of the road or other surface
Paved or unpaved, wet or dry, hard or soft, smooth or bumpy.
- The tire pressure
- If the tire is too soft, it can "sqirm" and deform itself so that it will not track properly when making turns.
- If the tire is too hard, it will bounce excessively on rough surfaces, bounding from bump to bump, spending too much time airborne.
- The shape and depth of the tire tread
This is mainly a concern in the case of tires for off-road use, where a knobby tire can get a bite of a soft or irregular surface.
For pavement riding, smooth tires get as good traction as those with tread, sometimes better. Aggressive knobby tread tires corner very poorly on pavement, because the tall knobs bend sideways under stress.
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- Trail is the distance from the contact point of the front wheel with the riding surface to the intersection of the steering axis (head tube) with the surface. The trail is a function of the head angle, the fork rake, and the tire diameter. Trail has a major effect on the handling of a bicycle. More trail increases the bicycle's tendency to steer straight ahead. A bicycle with a largish trail dimension will be very stable, and easy to ride "no hands". A bicycle with a smaller trail dimension will be more manuverable and responsive.
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- The horizontal cable linking the two arms of a cantilever or center-pull brake. Also called a "straddle" or "crossover" cable.
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- Short for rat traps.
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- In a bicycle suspension, the travel is the total distance that the wheel can move up and down, with respect to the frame.
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- The contoured surface of a tire, used to improve traction in loose or rough surfaces. Knobby or grooved tread designs have no real value for use on paved surfaces, and extreme tread patterns increase drag, noise and reduce cornering traction due to squirm. Despite appearances, slick tires perform best on hard surfaces.
- The lateral distance between the pedal attachment points on a crankset. For most cyclists, the narrower the tread the better. When we walk, our footprints fall almost in a straight line under the center-of-gravity of our bodies. When we cycle, the "tread" forces our feet to be exerting their force farther apart than they are designed to do. Some theorists blame this for knee and hip problems experienced by some cyclists, but the jury is still out on this.
A wider "tread" also creates a greater sideways force when pedaling out of the saddle, so the rider must exert more upper-body strength when riding "en danceuse".
A wider "tread" decreases pedal-ground clearance when the bicycle is banked over into a tight turn.
("Tread" in this sense is sometimes referred to as "Q-factor.")
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- A three-part race, usually consisting of a swim, a cycling stage, and a run.
The cycling section of a triathlon is run as if it were a time trial. Drafting is forbidden, so there can be no team tactics or other assistance between contestants.
The popularity of triathlons has brought many new participants to cycling, and because these participants are highly motivated but not in touch with many of the hidebound traditions of cycle racing, triathletes have introduced many fresh designs to cycling, most notably the æro handlebar.
Because of the lack of team tactics, and the tendency to use fairly flat courses for the cycling leg of triathlons, all sorts of ærodynamic parts and accessories have become popular among triathletes. This is helped by the fact that triathlons are not governed by the U.C.I. and there are very few restrictions on allowable equipment.
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- A crankset with three chainrings.
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- Double butted, but with different thickness butts on each end.
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- A tandem for three riders.
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- A type of tire mainly used for racing. A tubular tire has no beads; instead, the two edges of the carcass are sewn together (hence the term "sew-up") with the inner tube inside. Tubulars fit only on special rims, where they are held on by cement.
Tubulars use Presta valves. You should never use valve caps or other screwed-on valve accessories with tubulars.
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- Sarcastic slang term for extension levers.
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- A moderately rare style of crankset in which the axle and right crank/chainwheel are a single part, and the left crank attaches to the axle either with a cotter or by tightening a pinch bolt that holds the crank to a splined axle. These are usually found on low-quality bicycles and exercise machines of European manufacture. Most crank sets are three-piece, there are also one-piece crank sets.
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- British spelling of tire
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