Sheldon Brown's
Bicycle Glossary Ta - To
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This site contains several different articles about tandem bicycles.
| Size | Application | Metric drill | SAE drill |
|---|---|---|---|
| 3 mm | Adjusters in rear dropouts | ||
| 5 mm x .8 mm | Bottle cage mounts, fender eyelets, shift lever bosses. | 4.20 | #19 |
| 6 mm x 1mm | Cantilever bosses, some fender eyelets | 5 mm | #9 |
| 10 mm x 1mm | Derailer hangers | 9.0 mm | "T" |
| 1/2" x 20 L & R | Pedal threads for one-piece cranks | ||
| 9/16" x 20 L & R | Pedal threads for three-piece cranks | ||
| 1.375 x 24 tpi L & R | British/I.S.O. bottom brackets | ||
| 35 x 1mm L & R | French & Swiss bottom brackets | ||
| 36 x 1mm | Italian bottom brackets |
The corresponding nut-like tool for cutting external threads is called a die.
My Tool Tips series features an article on the use of taps.
To remove the sprocket from a threaded driver, the driver must be removed from the hub (otherwise it will just freewheel as you turn it counterclockwise.) As shown in the photo, one good way to secure it is to set it so that the legs are straddling a suitable steel bar, held in a vise. I use a pair of headset wrenches side-by-side, then unscrew the sprocket with a chain whip.
Threaded drivers are fairly rare, and are often sought after because they have the same thread as a standard freewheel hub. This makes it possible to create a hybrid gearing system by screwing a normal freewheel onto the driver. More details on this may be found in my article on my O.T.B. 63-speed bicycle.
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.
The table below is for threaded bottom-brackets. For the Ashtabula OPC and other unthreaded bottom brackets, see the unthreaded bottom-bracket cribsheet.
| Standard: | Threading | Adjustable (left) cup/cone direction |
Fixed (right) cup/cone direction |
Shell Width |
Applications/Notes |
|---|---|---|---|---|---|
| British I.S.O. |
1.370" X 24 tpi 1.375" X 24 tpi |
right | left | Standard 68 mm O.S. 73 mm |
The overwhelming majority of bicycles in current production. British and I.S.O. are interchangeable. |
| Shimano Hollowtech II, FSA MegaExo, RaceFace X-type | ISO | right | left | 90 mm, 95 mm including cups | External cups for cartridge bearings fit British/ISO threaded bottom brackets or unthreaded shell. 24 mm spindle, spacer to use 6805 bearings with 25mm I.D.. Bottom bracket shell must be faced so cups are parallel. |
| Campagnolo Ultra-torque | Italian or ISO | Spindle diameter 25mm. | |||
| Chater Lea | 1.450 x 26 TPI | right | left | Obsolete British size but available from Phil Wood & Co. | |
| French | 35 mm X 1mm (25.4 tpi) | right | right (wrong!) |
68 mm | Obsolete, used on older French bicycles. Prone to problems due to the right-threaded fixed cup, which tends to unscrew itself in use. |
| ISIS Overdrive I | 48 x 1.5 mm | right | left | 68mm 100 mm |
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| ISIS Overdrive II | 48 x 1.5 mm | right | left | 68mm 100 mm |
New proposed standard oversized system. |
| Italian | 36 mm X 24 tpi | right | right (wrong!) |
70 mm | Italian and some high-end French bicycles. Prone to problems due to the right-threaded fixed cup, which tends to unscrew itself in use. |
| Phil Wood American Isis (comments) | 50 mm | right | left | 1.5 mm thread pitch. | |
| Raleigh | 1 3/8" X 26 tpi | right | left | 71 mm 76 mm |
Older British-made Raleighs, 3 speeds and others from the Nottingham factory. |
| Swiss | 35 mm X 1mm (25.4 tpi) | right | left | 68 mm | Same thread as French, but fixed cup is left- threaded for reliability. |
| Bottom Bracket Shell Threading (Below) |
BritishI.S.O. 1.37/1.375" x 24 tpi CUPS R-L (34.8/34.9 x 1.06 mm) |
Italian 36 mm X 24 tpi CUPS R-R (1.417" x 1.06 mm) |
French 35 mm X 1mm CUPS R-R (1.378 x 25.4 tpi) |
Swiss 35 mm X 1mm CUPS R-L (1.378 x 25.4 tpi) |
Raleigh 1 3/8" X 26 tpi CUPS R-L (34.9 x 1.06 mm) |
|---|---|---|---|---|---|
| British/I.S.O. 1.37/1.375" x 24 tpi (34.8/34.9 x 1.06 mm) |
Made to Fit | 36 mm Cup diameter is too large, thread won't even start. | Cup diameter is slightly too large, usually won't start. Right (fixed) cup threaded in the opposite direction. |
Cup diameter is slightly too large, usually won't start. |
Diameter matches, but thread pitch does not.
Will bind after only a few threads are engaged. |
| Italian 36 mm X 24 tpi (1.417" x 1.06 mm) |
British/I.S.O. cups fall through | Made to Fit | Italian shells are larger diameter, all other size cups fall right through, threads will not engage. | ||
| French 35 mm X 1mm (1.378 x 25.4 tpi) |
35 mm = 1.378". Shell is slightly larger, thread pitch slightly finer. Left side may seem to fit, but will be loose. |
36 mm Cup diameter is too large, thread won't even start. | Made to Fit | Left (adjustable) side is interchangeable. Right (fixed) side is threaded in the opposite direction, won't fit. |
35 mm = 1.378". Shell is slightly larger, thread pitch slightly coarser. Left side may seem to fit, but will be loose. |
| Swiss 35 mm X 1mm (1.378 x 25.4 tpi) |
35 mm = 1.378". Shell is slightly larger, thread pitch slightly finer. May seem to fit, but will be loose. | 36 mm Cup diameter is too large, thread won't even start. | Left (adjustable) side is interchangeable. Right (fixed) side is threaded in the opposite direction, won't fit. |
Made to Fit | 35 mm = 1.378". Shell is slightly larger, thread pitch slightly coarser. May seem to fit, but will be loose. |
| Raleigh 1 3/8" X 26 tpi (34.9 x 0.977 mm) |
Diameter matches, but thread pitch does not.
Will bind after only a few threads are engaged. |
36 mm Cup diameter is too large, thread won't even start. | Cup diameter is slightly too large, usually won't start. Right (fixed) cup threaded in the opposite direction. |
Cup diameter is slightly too large, usually won't start. | Made to Fit |
| Type | Inch | Metric |
|---|---|---|
| Italian | 1.378" x 24 tpi | 35 x 1.058 mm |
| ISO | 1.375" x 24 tpi | 34.92 x 1.058 mm |
| British | 1.370" x 24 tpi | 34.80 x 1.058 mm |
| French | 1.366" x 25.4 tpi | 34.7 x 1 mm |
| Metric BMX | 1.181" x 25.4 tpi | 30 x 1 mm |
French and Metric BMX freewheels thread don't work with anything else.ISO, English and Italian are all semi-interchangeable, but it you shouldn't go back and forth between different types of freewheels on the same hub repeatedly.
Threaded Headsets/Steerers
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||||||
|---|---|---|---|---|---|---|
| Standard | Frame Cup Outside Diameter |
Crown race Inside diameter |
Steerer O.D in mm | Threads Per inch |
Stem diameter, Steerer I.D. |
Notes |
| 1" J.I.S. |
30.0 mm | 27.0 mm | 25.4 mm | 24 | 22.2 mm (7/8") | Older or lower-quality bicycles from Asia. Can be milled to ISO standard. ISO and other 30.2 mm O.D.cups are a very tight fit into the head tube; best mill it to avoid damage. |
| 1" Raleigh |
30.0 mm | 27.0 mm | 25.4 mm | 26 | 22.2 mm (7/8") | Proprietary size used on Raleighs made in Nottingham, England. ISO and other 30.2 mm O.D, frame cups are a very tight fit into the head tube; best mill to avoid damage. |
| 1" ISO Standard |
30.2 mm | 26.4 mm |
25.4 mm |
24 | 22.2 mm (7/8") | This is the standard 1" size. |
| 1" Professional/ Campagnolo |
30.2 mm | 26.4 mm |
25.4 mm | 24 | 22.2 mm (7/8") | Obsolete. Threads are cut at 55 degrees, but an ISO headset can be used. |
| 1" Italian | 30.2 mm | 26.5 mm, 27.0 mm |
25.4 mm | 24 | 22.2 mm (7/8") | Obsolete. Threads are cut at 55 degrees, but an ISO or J.I.S. top headset can be used. Fork can be milled to ISO. |
| French | 30.2 mm | 26.5 mm, 27.0 mm |
25.0 mm | 25.4 (1 mm) |
22.0 mm | Obsolete. French steerers usually have a flat filed on the back, rather than a grooved keyway as with other threaded systems. The bottom headset parts wear faster; you can replace them with ISO parts and use the old top headset. |
| East German (DDR) | 30.6 mm | 26.8 mm (1 1/8") |
26 mm | 26 | 22.0 mm | Very similar to or the same as Austrian. 0.2 mm discrepancy may result from measuring the I.D. of the head tube (press fit). See page on German site. |
| Austrian |
30.8 mm | 26.7 mm | 26 mm | 25.4 (1 mm) |
22.0 mm | These are found on bicycles sold by Sears, made by Steyr in Austria. Higher quality Austrian bikes use English/ISO. |
| BMX/ O.P.C. bikes | 32.6 mm (varies) |
26.4 mm (varies) | 25.4 mm | 24 | 21.15 mm (.833") |
Used mainly on bicycles with one-piece cranks, also some early mountain bikes. |
| French Tandem | Let us know, if you do! | 28 mm | Let us now, if you do! | 25.4 (1 mm) |
22.0 mm | Obsolete and rare. |
| 1 1/8" | 34.0 mm | 30.0 mm | 28.6 mm | 26 | 25.4 mm (1") | "Oversized" (This size is more often used for threadless systems.) |
| Moulton | 30.2 mm top, 36.4 bottom |
33.0 mm | 25.4 mm | 24 | 22.2 mm (7/8") |
Moulton Mark III and earlier. Top headset is standard ISO. |
| 1 1/4" | 37.0 mm | 33.0 mm | 31.8 mm | 26 | 28.6 mm (1 1/8") | Mainly used on tandems |
Metric threads are specified by diameter followed by the thread pitch (distance between threads)
For example, the common "M5" thread used for water bottle mounts, cable anchor bolts, fender/rack eyelets, shifter mounts etc. bicycles is more specifically described as "5.0 x 0.8" which specifies a 5 mm diameter, with threads 0.8 mm apart.
Similarly, the common "M6" thread used for brake mounting bolts, threadless stems, many seatpost bolts and so forth is actually "M6.0 x 1.0" That's 6 mm diameter, threads 1 mm apart.
Normal coarse metric threads are commonly designated with the letter "M" followed by the diameter, with the thread pitch understood. For example:
See the Headset entry for details and adjustment instructions.
The original style of shifter used on mountain bikes, up until the early '90s.
When the Shimano Rapidfire ® and Sun Tour X-Press ® shifters hit the market, confusion resulted, because these, too were operated by the thumbs. This confusion persists, so it is a good idea to avoid the term "thumb shifter." The newer term for these is "top-mount" shifters, as opposed to "below-the-bar" shifters, such as Rapidfire.
T.I.G. welding is commonly used to build lugless bicycle frames. Most current bicycle frame production is done by T.I.G. welding.
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.
A tire is actually made up of three parts:
This site includes an extensive article on Tires and also an article explaining the different Tire Sizing systems.
One or two tire levers are usually enough to get all but the most recalcitrant tire beads over the rim, but in extreme cases you may need three. When the third is in place, the middle one can be removed and re-inserted farther over. Tire levers are usually sold in sets of three, since you never need more than three.
Since most newer tire levers are made of plastic, the term "tire iron" is a bit anachronistic.
See my Article on Frame Materials.
The only time it can happen is when the handlebars are turned quite far to the side, as only happens at very low speeds.
Many, many people ride bicycles with fairly severe overlap with no practical problems, sometimes having to make a slight adjustment to their pedaling habits at very slow speeds.
On smaller-size bikes with full-sized wheels, it is usually impossible to eliminate overlap without causing adverse fit/handling issues.
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.
Brake shoes that are longer to the rear of the post will press more evenly on the rim. 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. That is not a good idea with aluminum brakes-- it can initiate cracking, which leads to failure.
A peculiarity of Top-Swing ® derailers is that the limit stop adjustment screws are reversed, so that the outer screw limits inward travel, and vice versa.
Top-Swing ® derailers clamp on to the seat tube lower down than bottom-swing units. (Shimano E-type derailers don't even attach to the seat tube, but are held on by the bottom bracket mounting ring.) Some frames made for use with top-swing derailers will not permit the installation of conventional bottom-swing derailers, because there's a bottle braze on in the way. Some suspension frames also require a top-swing front derailer for clearance reasons.
Top-Swing ® or bottom-swing derailers can be (and are) made in either top-pull or bottom-pull versions. (This has to do with the direction from which the cable approaches.)
The length of the top tube is probably the most important dimension in providing a comfortable fit. See my article on Frame Sizing.
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.
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 energy/work 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 energy/work, not torque.
This is primarily an automotive tool, especially useful for applications involving crushable gaskets which must be tightened evenly.
Torque wrenches are never needed for bicycle work, although they can be a useful training aid for inexperienced mechanics who haven't learned the feel of a properly-tightened fastener.
[I find this mostly to be true, but many bicycle components now are accompanied with spec sheets with lists of torque settings. There are three reasons for this:
This paragraph added by John Allen]
Also see the more extended discussion about torquing threaded parts.
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.
Traditional British touring bags are roughly cylindrical (oriented crossways-no attempt is made to make them aerodynamic) though they add little drag, because they are behind the cyclist. 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, Karrimor and Zimbale. The better-quality bags are made of heavy black canvas, with gray"chrome" leather straps and corner reinforcements. In the USA, Dill Pickle Gear makes nice touring bags to order.
Most Brooks saddles have strong, steel bag loops. It may be necessary to rotate the springs of a sprung saddle so the straps will feed through easily past the coils. Loops can eventually cut through the straps, though some have smooth metal inserts. Brooks sells the eyelets, replacement part BYB 323, which will fit bag loops with a long, narrow (not triangular) slot.
A saddle without eyelets. The sharp edges of the bag loops
can cut bag straps.
A saddle retrofitted with eyelets.
Rotating the springs can make it easier to insert bag straps
on a saddle with springs.
Filing the loops smooth can help. Carry a pair of extra toe straps to use as replacement straps, just in case.
Pop quiz: what's wrong with this picture?
Answer: the straps are threaded onto the springs, rather than through the bag loops -- but also, for the greatest stability, the buckles should be inside the bag, allowing it to be snugged up against the bag loops.
Straps inside bag.
Bag snugged up against loops.
Still, these bags are not ideal for cyclists who like to stand up and thrash their bicycles from side to side while climbing, due to sway. For the cyclist with a smooth riding style, these bags offer a good option for carrying a sizeable load on a bicycle which lacks pannier racks -- or to provide extra capacity.
This type of bag is currently enjoying a resurgence of popularity.
In case you might possibly have other questions about the picture, a further explanation is available.
A touring bicycle is designed for comfort, durability, efficiency and, in most cases, load-carrying capacity. Touring bicycles fall into two major groupings:
A well-equipped loaded-touring bicycle will usually have:
Increasingly, loaded touring is being done on modified mountain bikes, which share many characteristics with loaded tourers.
Some riders prefer to use trailers instead of panniers to carry their camping equipment.
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:
Last Updated: by Harriet Fell