Adjusting Cantilever Bicycle Brakes

( This information is from Sheldon Browns website.)

 

Bicycle Rim brakes divide into two basic types: cantilever and caliper.

Caliper brakes are self-contained mechanisms, attached to the bicycle's frame by a single bolt for each brake, front & rear. The arms reach downward from above the tire, and need to be long enough to get around the tire.

Cantilever brakes attach to the sides of a bicycle's frame/fork, separately on each side. They can only be used on bikes that are designed to use them, because they require special brazed-on fittings on the frame. These fittings are commonly called "studs" or "bosses." The brake for each wheel consists of two separate arms, each of which is individually attached to the frame or fork.

Cantilever brakes further divide into four sub-types, and I have reorganized this page into 4 separate pages, each dealing with one of the four sub-types. Click on the heading to go to the relevant page:

Direct Pull "V-Brakes ®" This is the type used on most bikes made since the mid 1990s. This is the only style of cantilever where the cable comes to the cantilever set from one side, rather than down the middle.
Center-pull (Traditional) Cantilevers These were used on almost all mountain bikes made before the mid 1990s, and are still popular on touring and cyclocross bicycles. See my separate article on adjusting this type of brake
U-Brakes These were fashionable for mountain bikes around 1987, typically mounted underneath the chain stays. U-brakes have had a bit of a revival in the last few years for use on freestyle bicycles (Functionally, U-brakes are very similar to the center-pull caliper brakes popular on sport bikes of the 1960s and '70s.)
Roller Cam Brakes The Roller Cam cantilever brake was a predecessor of the U-brake, and had a brief vogue in the mid 1980s. (Unit shown is a contemporary roller cam caliper brake.)

Cantilever Brake Compatibility/Interchangeability
Cantlever Type	Frame Pivot Studs	Levers	Cable Routing
Direct Pull V-Brake ®	Below the Rim	Long Pull Low Tension	Cable comes in from the side. Lower housing stop is part of the cantilever
Traditional Center Pull		Standard Short Pull High Tension	Cable runs down the bicycle's center line. Lower rear housing stop on frame, either special braze-on , or mounted to the seatpost bolt. Front housing stop on headset , fork or handlebar stem .
U-Brake Cantilever	Above the Rim
Roller-Cam Cantilever

Good Cable Installation For Good Braking And Shifting
Gear shift and brake cables often show the difference between a hastily assembled bike and one which has been assembled by a mechanic who cared what he or she was doing.
Especially now that new handlebar designs seem to come along every week, a good mechanic must understand the theory of routing cables. One can no longer rely on a couple of rote "rules of thumb" for routing cables correctly.

Although people pay a lot of attention to what kind of derailers and brakes are fitted to a particular bicycle, good cable installation practices are more important than most differences between different brake and shift systems. The most expensive brakes and derailers will work poorly if there is excessive friction or play in their control cables. Even cheap brakes and derailers can often be made to perform satisfactorily if care is used in installing the cables.

The great majority of service problems with brakes and gears are the result of cable friction, not deficiencies in the levers, calipers or derailers.

How Cables Work
Cables used on bicycles are in two parts. The inner wire is made of twisted strands of steel. The outer housing is also made of flexible steel, usually wound in a spiral. The inner wire runs down the middle of the housing. Both parts are equally important, neither can work without the other.
Isaac Newton said "For every action, there is an equal and opposite reaction." In the case of bicycle cables, this means that there cannot be a pull on an inner cable without an equal push on the housing.

To save weight, many bicycles substitute the bicycle frame for some sections of the housing. This is done by attaching "cable stops" to the frame or fork. A cable stop has a socket to receive an end of a cable housing, and a small hole or slot through which the inner cable can pass, but the housing can't. The "push" of the housing is transferred to the frame, so the inner wire can run bare until it gets to another cable stop facing the other way, where the "push" from the frame is transferred back to another length of housing.

This "bare cable" routing can be done anywhere that the cable runs in a straight line, and doesn't have to bend. Housing must be used from the handlebars to the frame, to accommodate the turning of the handlebars as the bicycle is steered. Lengths of housing are also commonly used when the direction of pull of the cable must be changed.

Types of Cable Housing
Conventional Spiral Housing
At first glance, many people assume that cable housing is made of plastic. Actually, it is steel, and the plastic is a covering to protect it from moisture, and to keep it from scratching the paint of the bicycle.
Traditional cable housing is a tightly-wrapped spiral of steel wire, sort of like a small-diameter Slinky. It has no particular strength in tension (pulling) but it cannot be compressed because the coils of wire are tight against one another.

Through the 1970's, the inner wire ran right through the steel spiral housing, usually using grease for lubrication. Modern housing, however has a plastic liner which surrounds the inner wire. This considerably reduces the friction. Some high-end cable systems, such as the Gore-Tex "Ride-On" cables, extend this liner even along the areas where there is no housing. These systems also have a special friction-reducing coating on the inner wires.

Compressionless "Index-compatible" Housing
With the advent of indexed shifting combined with handlebar mounted shift levers, it developed that conventional housing was a source of imprecise shifting. This is because the effective length of the housing changes as it is bent. This is not a problem with brakes: Although sometimes it will be noted that rear brakes may drag slightly when the handlebars are turned all the way to one side, you can't turn the bars that far when the bike is actually in motion.
This small variation in housing length was too much for reliable indexed shifting, however, so Shimano introduced "S.I.S." housing, now widely copied by other manufacturers. This type of housing does not consist of a single spiral-wound wire, but a bundle of wires running pretty much straight along parallel to the housing. They are held in place by the fact that they are sandwiched between the plastic housing liner and the plastic outer covering.

"Compressionless" housing doesn't change length significantly as it is flexed, so the indexed shifter is able to communicate the correct setting to the derailer, even as the handlebars are turned, and the loops of cable housing bounce up and down due to bumps.

Warning: Since compressionless housing relies on plastic to hold it together, it is not as strong as conventional spiral housing, and should never be used for brakes! The loads applied to brake cables can easily cause compressionless housing to rupture and burst, causing a complete and sudden loss of brake function.

Good Cable Installation For Good Braking And Shifting

Gear shift and brake cables often show the difference between a hastily assembled bike and one which has been assembled by a mechanic who cared what he or she was doing.

Especially now that new handlebar designs seem to come along every week, a good mechanic must understand the theory of routing cables. One can no longer rely on a couple of rote "rules of thumb" for routing cables correctly.

Although people pay a lot of attention to what kind of derailers and brakes are fitted to a particular bicycle, good cable installation practices are more important than most differences between different brake and shift systems. The most expensive brakes and derailers will work poorly if there is excessive friction or play in their control cables. Even cheap brakes and derailers can often be made to perform satisfactorily if care is used in installing the cables.

The great majority of service problems with brakes and gears are the result of cable friction, not deficiencies in the levers, calipers or derailers.

How Cables Work

Types of Cable Housing

Conventional Spiral Housing

Compressionless "Index-compatible" Housing

Cutting Housing and Preparing the Ends

• Spiral Housing

  Conventional spiral housing can be cut with a good diagonal cutter or a shear cutter made for bicycle cables. When you cut the housing, sometimes the cut will be a clean one, but other times, the last loop on the spiral may get crushed down, partially blocking the passage that the inner cable must slide through. Usually, you can make a second cut and trim off the bent half-loop.

  Even when the housing is cut cleanly, the end is not square and perpendicular, due to the pitch of the spiral. Careful mechanics will grind or file the end of the housing so that it is flat and flush. The best tool for this is a grinding wheel, but it can be done with a flat file. Lay the file on the workbench and hold the end of the cable vertical as you stroke it along the file.

  When you cut the housing, the end of the plastic liner also gets cut, and often gets squashed flat. You can use a scriber or a sharp awl to open it up and round it out. If you use a grinding wheel to dress the end of the housing, have your scriber right at hand so that you can open up the plastic liner immediately after grinding. The heat from the grinding will partially melt the liner. By sticking the scriber in before the liner cools off, you can not only round out the end, but the shape of the scriber will actually flare the end a bit for a smoother transition.

  

  Raw Cut End		Finished End

• Compressionless Housing

  It is very difficult to cut compressionless housing without the proper tools. There are special shear-type cable cutters made for the purpose, which have notched blades that encircle the housing so as not to crush it too badly while cutting it.

  Some people who don't have access to one of these cutters use a hand-held grinder (such as a Dremel tool) with a thin abrasive "cut-off wheel."

  It is not necessary to grind the ends of compressionless housing, because, if you cut it with an appropriate tool, it comes out flat. It is still usually necessary to open up the end of the plastic liner with a scriber or awl.

  The final loop at the rear derailer is short and has a nearly 180 degree bend. "Compressionless" housing is normally used for this. I've taken to bending the piece of housing to the approximate shape it will be used in before cutting it.

  If you cut the housing straight, all of the longitudinal wires come out the same length, so when you bend it, the end of the housing acquires a slanted face, since the wires on the inside of the bend have a longer way to go around the curve. It is my belief that cutting the housing while it is bent makes a smoother, more reliable connection at the end of the housing.

• Ferrules

  Ferrules are small metal caps, usually nickel-plated brass, which fit over the end of a piece of cable housing. They help keep the housing aligned with the cable stop it fits into. Whenever possible, you should fit a ferrule on each end of a cut piece of housing. Some housing stops/adjusting barrels are too small to fit a ferrule into, so you don't always need to use one. Such stops will generally be a snug enough fit that they will act as a ferrule.

The use of ferrules is particularly important with compressionless housing, because the thin longitudinal wires of the housing can poke out through the hole in a cable stop, around the inner wire. This is a common reason for indexed shifting to go out of adjustment. Make sure that the ferrule fits tightly around the inner wire, or you may still have this problem!

Cable Routing

The Four Commandments of Cable Routing:

1. The handlebars must be able to turn as far as they can in both directions without being limited by a cable pulling taut. Instead, the turning limit must be set by the handlebar bumping into the top tube or by the brake arm or reflector bracket bumping into the down tube.
2. No wrong-direction bends (For example: as the rear brake cable leaves the top tube and makes the bend down toward the caliper, it should make a smooth transition from parallel to the top tube to parallel to the seat stays. If the cable bends up from the top tube before bending down toward the seat stays, it is probably too long. If the cable curves out past the caliper, then bends back at an angle more vertical than the seat stays, it is certainly too long.
3. The bends that cannot be avoided should be made as wide (gradual) as possible,
4. Cable housings should be as short as they can be without violating the above rules.

Brake Cable Routing

• Drop Handlebars
  • Traditional brake levers (with exposed cables.)
    • The traditional way to run exposed cables is so that they loop up and over the back of the handlebars. This provides the smoothest, most gradual curves in most cases, and minimizes interference with a handlebar bag.
    • In the case of bicycles with cyclecomputers or stem shifters, it is usually preferable to run the cables under the bars so that they won't encumber access to the computer or shifters.
    • Under-the-bar routing is also desirable for bicycles with unusually tall or short-reach stems, so that the rear cable won't have to make a sharp bend at the top tube.
    • Don't mix systems: either run both brake cables over the bars or both under. This is for æsthetic reasons, not mechanical ones.
  • "Æro" brake levers (cables run under the handlebar tape.)
    • The usual set-up involves running the cables along the inside of the upper part of the handlebar, tightly secured to the bar with tape. It is important that the housing be tightly wrapped against the handlebar, or the braking may be spongy.

      To ensure firm contact of the housing against the stop inside the brake lever, the cables should be fully connected and put under tension before they are taped down. One good way to do this is to use a toe strap to hold the brake lever tightly applied while securing the section of housing that runs along the handlebar. It is good practice to use electrical tape or other adhesive tape to secure the cable housing against the handlebar. If you do so, it is easier to apply the normal handlebar tape afterwards, or to replace the handlebar tape at a later date.

    • The rear brake cable can go on either side of the head tube. When the handlebars are turned as far as they can go in one direction, they will pull the cable tight. In the other direction, they will create more slack in the housing. In the case of bicycles with sidepull brakes, the upper arm of the front brake limits the handlebar turning scope in one direction, as the brake arm comes into contact with the down tube.

      The rear brake cable should go on the side of the stem opposite of the front brake cable...this way you will not have to allow so much extra slack in the rear cable, since the handlebars can't turn as far in the direction that will tighten the rear cable

• Upright Handlebars
  • Normally, both cables run under the handlebars.
  • If the handlebar stem is drilled through to act as a cable stop, the front brake will need to loop over the bar.
  • The rear brake cable should cross over around the stem, unless there is an off-center cable stop on the side of the top tube nearest the rear brake lever.

  This cable is too long:

  

  This cable is correct:

  

  This cable is too short:

  
• Right Front or Left Front? The usual system is to have the rear brake controlled by the lever on the side of the bicycle that corresponds to the side of the road that it will be driven on, i.e., right in most of the world; left in the British Isles, Japan, and other places where they drive on the left.

  Nobody knows exactly why this is. My theory is that it is based on the reasonable idea that you should be able to have your primary braking hand on the handlebars while making a turn signal with the appropriate hand -- coupled with the erroneous idea that the rear brake is the primary brake.

  I prefer to set my own bicycles up with the front brake controlled by the right lever. This allows me to signal and stop at the same time, and also lets me use my stronger, more skillful hand for the more critical front brake. (I rarely use my rear brake.)

  Since this is the opposite of the prevailing national standard, I would never set up a bicycle this way for a customer without a specific request to do so. I have an article on Braking and Turning which addresses these issues in more detail.

Cable Adjustment

Shifter cables

Brake cables

Reach Adjustment

Gear Cable Routing

Over or Under the Bottom Bracket?

• Over Up until the mid-1980's, the usual way to run gear cables was above the bottom bracket, either using short pieces of cable housing, or, more commonly, simple guides, either brazed on to the bottom bracket shell, or clamped to the frame. From the guide, the rear cable would run along the top of the right chain stay to a cable stop at the rear of the stay, for the final loop to the rear derailer.

  This worked quite well, until mountain bikes came on the scene and made granny gears a standard item. The problem was that the extended cage of a wide-range front derailer would interfere with the rear gear cable.

• Under The popular solution to this problem was to run the cable under the bottom bracket shell, and move the chainstay cable stop to the underside of the chainstay. This had the added advantage of being cheaper--a simple plastic block bolted or riveted to the underside of the bottom bracket shell took the place of a brazed-on or clamped-on set of guides. Most multi-speed bicycles are now made this way.

  Unfortunately, this routing tends to degrade shifting somewhat. Locating the chainstay cable stop down below creates a sharper curve for the final loop of housing, and also exposes the entrance to that loop to crud splashed up by the front wheel. The bottom-bracket guide, whether over or under the bottom bracket, is also exposed to sprayed mud and crud from the front wheel...a particular problem for off-road cyclists.

• Top routing The third option, increasingly popular for mountain bikes, involves bypassing the bottom bracket altogether, and running both gear cables along the top tube. The rear cable runs down along the seat stay, and the front runs down the back of the seat tube.

  When this style first arose, in the early '90's, the front derailer was a problem, since existing front derailers were intended to be operated by a cable pulled from below. Early top-routing schemes used brazed-on pulleys on the back of the seat tube, a rather mono-buttocked solution, in my opinion. This problem has been solved by the ready availability of "top-pull" front derailers.

Autoshifting

"Criss-Cross" Cables

The SRAM Bassworm and Nightcrawler

Lubrication

Cable Lubrication

Hardware Lubrication

Take The Trouble To Do It Right

 

Which Size Tire Fits Which Size Rim?

Bicycle tires come in a bewildering variety of sizes. To make matters worse, in the early days of cycling, every country that manufactured bicycles developed its own system of marking the sizes. These different national sizing schemes created a situation in which the same size tire would be known by different numbers in different countries. Even worse, different-sized tires that were not interchangeable with one another were often marked with the same numbers!

Traditional Sizing Systems

The traditional sizing systems are based on a measurement of the outside diameter of a tire. This would usually be measured in inches (26", 27", etc.) or millimeters (650, 700, etc.).

Unfortunately, evolution of tires and rims has made these measurements lose contact with reality. Here's how it works: Let's start with the 26 x 2.125 size that became popular on heavyweight "balloon tire" bikes in the late '30's and still remains common on "beach cruiser" bikes. This size tire is very close to 26 inches in actual diameter. Some riders, however were dissatisfied with these tires, and wanted something a bit lighter and faster. The industry responded by making "middleweight" tires, marked 26 x 1.75 to fit the same rims. Although they are still called "26 inch", these tires are actually 25 5/8", not 26". This same rim size was adopted by the early pioneers of west-coast "klunkers", and became the standard for mountain bikes. Due to the appetite of the market, you can get tires as narrow as 25 mm to fit these rims, so you wind up with a "26 inch" tire that is more like 24 7/8" in actual diameter!

A second number or letter code would indicate the width of the tire. (26 x 1.75, 27 x 1 1/4...650B, 700C...)

Does Point Seven Five Equal Three Quarters?

Note that the inch-based designations sometimes express the width in a decimal (26 x 1.75) and sometimes as a common fraction (26 x 1 3/4). This is the most common cause of mismatches. Although these size designations are mathematically equal, they refer to different size tires, which are NOT interchangeable. It is dangerous to generalize when talking about tire sizing, but I would confidently state the following:

Brown's Law Of Tire Sizing:

If two tires are marked with sizes that are mathematically equal,
but one is expressed as a decimal and the other as a fraction,
these two tires will not be interchangeable.

Dishonesty in Sizing

Competitive pressures have often led to inaccuracy in width measurement. Here's how it works: Suppose you are in the market for a high performance 700 x 25 tire; you might reasonably investigate catalogues and advertisements to try to find the lightest 700-25 available. If the Pepsi Tire Company and the Coke Tire Company had tires of equal quality and technology, but the Pepsi 700-25 was actually a 700-24 marked as a 25, the Pepsi tire would be lighter than the accurately-marked Coke 700-25. This would put them at a competitive advantage. In self defense, Coke would retaliate by marketing an even lighter 700-23 labeled as a 700-25.

This scenario prevailed throughout the '70's and '80's. The situation got so out-of-hand that cooler heads have prevailed, and there is a strong (but not universal) trend toward accurate width measurements.

B.S.D.

The ISO (E.T.R.T.O.) System:

ISO, the International Organization for Standardization has developed a universal tire sizing system that eliminates this confusion. (This system was formerly known as the "E.T.R.T.O." system, developed by the European Tyre and Rim Technical Organisation.)
The ISO system uses two numbers; the first is the width of the tire or rim in millimeters (The actual tire width will vary a bit depending on the width of the rim. The rim width is the inner width measured between the flanges as shown in the diagram.)

The second ISO number is the critical one, it is the diameter of the bead seat of the rim, in mm ("B.S.D."). Generally, if this number matches, the tire involved will fit onto the rim; if it doesn't match, the tire won't fit.

For example, a 700 x 20 C road tire would be a 20-622; a 700 x 38 hybrid tire would be a 38-622. The width difference between these sizes would make them less-than ideal replacements for one another, but any rim that could fit one of them would work after a fashion with the other.

A general guideline is that the tire width should be between 1.45/2.0 x the inner rim width.

If you flatten out a tire and measure the total width from bead to bead, it should be approximately 2.5 x the ISO width.

If your tire is too narrow for the rim there's an increased risk of tire/rim damage from road hazards.

If its too wide for the rim, there's an increase risk of sidewall wear, and a greater risk of loss of control in the event of a sudden flat.

The following is a partial listing of traditional tire sizes that are sometimes seen in the U.S., with their ISO bead seat equivalents.

Fractional sizes:

Fractional ISO Applications
29 inch 622 mm This is a marketing term for wide 622 mm ("700c") tires.
28 x 1 1/2 635 mm English, Dutch, Chinese, Indian Rod-brake roadsters
(Also marked F10, F25, 700 B)
622 mm (F.13)Rare Canadian designation for the (F.13)
28 x 1 5/8 x 1 1/4 Northern European designation for the 622 mm (700 C) size
27 x anything 630 mm Older road bikes
26 x 1 (650 C) 571 mm Triathlon, time trial, small road bikes
26 x 1 1/4 597 mm Older British sport & club bikes
26 x 1 3/8 (S-6) 597 mm Schwinn "lightweights"
26 x 1 3/8 (E.A.3) 590 mm Most 3-speeds, department-store or juvenile 10 speeds
26 x 1 1/2 (650B) 584 mm French utility, tandem and loaded-touring bikes,
a very few Raleigh (U.S.) & Schwinn mountain bikes.
26 x 1 3/4 (S-7) 571 mm Schwinn cruisers
24 x 1 520 mm High performance wheels for smaller riders; Terry front
24 x 1 1/8 520 mm or
540 mm! Caveat emptor!
24 x 1 1/4 547 mm British or Schwinn Juvenile
24 x 1 3/8 (S-5) 547 mm Schwinn Juvenile lightweights
24 x 1 3/8 (E-5) 540 mm British Juvenile, most wheelchairs
20 x 1 1/8
20 x 1 1/4
20 x 1 3/8 451 mm Juvenile lightweights, BMX for light riders, some recumbents
20 x 1 3/4 419 mm Schwinn juvenile
17 x 1 1/4 369 mm Alex Moulton
16 x 1 3/8 349 mm Older Moulton, Brompton & other folders, Recumbent front, juvenile
16 x 1 3/8 337 mm Mystery tire
16 x 1 3/8 335 mm Polish juvenile
16 x 1 3/4 317 mm Schwinn Juvenile
12 1/2 x anything 203 mm Juvenile, scooters
10 x 2 152 mm Wheelchair
8 x 1 1/4 137 mm Wheelchair
Traditionally, fractional sizes are made for straight-sided rims.
High-performance sizes (571 mm /26 x 1 & 630 mm /27") have evolved toward hook-edged rims.

Decimal sizes:

Decimal ISO Applications
29 inch 622 mm This is a marketing term for wide 622 mm ("700c") tires.
28 x decimal 622 mm Some German tire companies use this non-standard designation for 622 mm ("700c") tires.
26 x 1.00 through 2.3 559 mm Most Mountain bikes, cruisers, etc. except:
26 x 1.25 (rare) 599 mm Very old U.S. lightweights
26 x 1.375 599 mm Very old U.S. lightweights
24 x 1.5-24 x 2.125 507 mm Juvenile mountain bikes, cruisers
22 x 1.75, 22 x 2.125 457 mm Juvenile
20 x 1.5-20 x 2.125 406 mm Most BMX, juvenile, folders, trailers, some recumbents
18 x 1.5 355 mm Birdy folding bikes
18 x 1.75-18 x 2.125 355 mm Juvenile
16 x 1.75-16 x 2.125 305 mm Juvenile, folders, trailers, some recumbents

 

French sizes:

In the French system, the first number is the nominal diameter in mm, followed by a letter code for the width: "A" is narrow, "D" is wide. The letter codes no longer correspond to the tire width, since narrow tires are often made for rim sizes that originally took wide tires; for example, 700 C was originally a wide size, but now is available in very narrow widths, with actual diameters as small as 660 mm.

French Size ISO Applications
700 A 642 mm Obsolete
700 B 635 mm Rod-brake roadsters.
700 C 622 mm Road bikes, hybrids, "29 inch" MTBs.
(28 x 1 1/2 F.13 Canada)
700 D 587 mm Oddball size formerly used on some GT models.
650 A 590 mm French version of 26 x 1 3/8; Italian high-performance bikes for smaller riders
650 B 584 mm French utility bikes, tandems, and loaded-touring bikes; some older Raleigh and Schwinn mountain bikes
650 C 571 mm Triathlon, time trial, high performance road bikes for smaller riders
600 A 540 mm European Juvenile road bikes, most wheelchairs
550 A 490 mm European Juvenile road bikes
500 A 440 mm European Juvenile, folding
450 A 390 mm European Juvenile
400 A 340 mm European Juvenile

 

ISO Cross Reference:

ISO Bead Seat Diameter Traditional Designations
635 mm 28 x 1 1/2, 700 B
630 mm 27 x anything
622 mm 700 C, 28 x (two fractions), 29 inch
(28 x 1 1/2 F.13 Canada)
599 mm 26 x 1.25, x 1.375
597 mm 26 x 1 1/4, 26 x 1 3/8 (S-6)
590 mm 26 x 1 3/8 (E.A.3), 650 A
587 mm 700 D
584 mm 650B, 26 x 1 1/2
571 mm 26 x 1, 26 x 1 3/4, 650 C
559 mm 26 x 1.00- x 2.125
547 mm 24 x 1 1/4, 24 x 1 3/8 (S-5)
540 mm 24 x 1 1/8, 24 x 1 3/8 (E.5), 600 A
520 mm 24 x 1, 24 x 1 1/8
507 mm 24 x 1.5- x 2.125
490 mm 550 A
457 mm 22 x 1.75; x 2.125
451 mm 20 x 1 1/8; x 1 1/4; x 1 3/8
440 mm 500 A
419 mm 20 x 1 3/4
406 mm 20 x 1.5- x 2.125
390 mm 450 A
369 mm 17 x 1 1/4
355 mm 18 x 1.5- x 2.125
349 mm 16 x 1 3/8
340 mm 400 A
337 mm 16 x 1 3/8
317 mm 16 x 1 3/4
305 mm 16 x 1.75- x 2.125
203 mm 12 1/2 X anything.
152 mm 10 x 2
137 mm 8 x 1 1/4

Most of this information was compiled by John Allen for Sutherland's Handbook For Bicycle Mechanics, the bible of bicycle technology. Sutherland's has a more detailed, more thorough version of this chart.

Got an unmarked rim but no tire? Click Here for how to measure Rim Size.

Width Considerations

Although you can use practically any tire/rim combination that shares the same bead seat diameter, it is unwise to use widely disparate sizes.
If you use a very narrow tire on a wide rim, you risk pinch flats and rim damage from road hazards.

If you use a very wide tire on a narrow rim, you risk sidewall or rim failure. This combination causes very sloppy handling at low speeds. Unfortunately, current mountain-bike fashion pushes the edge of this. In the interest of weight saving, most current mountain bikes have excessively narrow rims. Such narrow rims work very poorly with wide tires, unless the tires are overinflated...but that defeats the purpose of wide tires, and puts undue stress on the rim sidewalls.

Georg Boeger has kindly provided a chart showing recommended width combinations:

Which tire fits safely on which rim?
[all dimensions in millimeters]
Tire width
Rim width
(interior) 18 20 23 25 28 32 35 37 40 44 47 50 54 57
13 X X X X
15 X X X X
17 X X X X X
19 X X X X X X
21 X X X X X X
23 X X X X
25 X X X X X

Note: This chart may err a bit on the side of caution. Many cyclists exceed the recommended widths with no problem.

Wilderness Trail Bikes' Global Measuring System

From the WTB Website:

GMS Global Measuring System The current industry standard for specifying the actual inflated size of a bicycle tire does not account for subtle variation in tread and casing size. To address this problem and provide you with more information for comparing tires, WTB has introduced the Global Measuring System (GMS) for tire measurement.
The GMS uses a two-number system: the first number is the width of the casing, and the second number is the width of the tread, both in millimeters. These measurements are taken on a rim which is 20 mm wide at the bead-capturing point, with a tire inflated to 60psi and maintained for 24 hours.

In addition to being able to accurately size a tire, knowing the actual casing size and tread width provides an indication of air volume, tread characteristics and tread contact area; all of which provide you with a more concise idea of what ride characteristics to expect from each of WTB's tires.

 

Tubular Tires ("Sew-ups")

Tubular tires are 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 existed in 6 different sizes, but only two of them are readily available these days.

Full-sized tubulars fit rims of the same diameter as 622 mm (700c) clinchers. This size is sometimes referred to as "28 inch" or "700". It is also, confusingly, sometimes referred to as "27 inch." The "27 inch" designation is inaccurate and obsolete, but you'll sometimes run into it in older printed material.
In clincher tires, there is a real difference between "700c" and "27 inch" sizes, but for tubulars this is a false distinction. Whenever you see mention of "27 inch tubulars" the writer is actually referring to standard full-sized tubulars, as used on most racing bikes.

"26 inch" or "650" tubulars are smaller, mainly used on time-trial or motorpacing track bikes.
"24 inch", "22 inch" "20 inch" and "18 inch" tubulars are sizes formerly used for children's racing bikes, but pretty much extinct these days.
Tubulars are also sometimes called "sew-ups" or "tubs" (British usage.)
If you want to sound like an ignorant yahoo, call them "tubies" or "tubeless tires."

 

Learning to Use The Front Brake

When to Use The Rear Brake

When to Use Both Brakes Together

Which Brake Which Side?

 

Leaning in Turns

A letter to Bike Culture:

 

 

Second Life Bikes

21 Main Street

Asbury Park, NJ  07712

No car parking in front on Main Street.

Hours:  Tuesday-Saturday   10am-5:30pm

Donations, repairs, browsers, visitors and volunteers are all welcome during those times.

732-776-6878

Email contact:  kerri@secondlifebikes.org