Sheldon Brown's Bicycle Glossary Ca-Ce

In many installations the housing doesn't run along the full length of the cable, but transmits the compressive part of the load to the frame by means of housing stops, fittings with holes small enough for the cable, but not small enough for the housing to pass through. Some cable stops feature adjusting barrels. This site features an extensive Article on Cable Installation.

Older derailer bikes used either brazed-on or clamp-on guides just above the bottom bracket, but newer bicycles have a guide under the bottom bracket.

The below-the-bottom-bracket option has the advantage of being cheaper, and, for some bikes with very small chainweels, it eliminates interference betwixt the rear derailer cable and the bottom of the front derailer cage. It also makes it slightly easier to clean the frame cosmetically.

The above-the-bottom-bracket system is superior in that the cable is shorter and the loop of housing at the rear derailer is not as tight, since the cable stop is atop the chainstay, rather than beneath it.

Poor lubrication of bottom-bracket cable guides is a common cause of autoshifting. Some bicycles use a cable guide on one side of the seat cluster for a rear cantilever brake cable, rather than use a short length of housing between two housing stops.

Most experienced cyclists pedal at cadences in the range of 70-90 RPM. This puts less strain on the joints, particularly the knees. Racing cyclists often use even higher cadences for bursts of accelleration.

1. A metal or plastic holder for the bearing balls in a ball bearing. Use of a cage keeps the balls from bumping into one another, and allows the use of fewer balls. In the case of traditional cup-and-cone bearings used on bicycles, the primary purpose of caged balls is to save labor. More formally known as a retainer.

2. A holder for carrying a water bottle.

3. The part of a derailer through which the chain passes. The front derailer cage is a simple guide, the rear derailer cage contains the jockey pulley and the tension pulley.

4. The outer part of a conventional pedal, the part that comes into contact with the rider's shoe.

5. The part of an internal gear hub which holds the planet pinions.

6. Slang term for an automobile; a "cager" is the driver of an automobile.

Most bicycle brakes use a similar mechanism to move the brake shoes inward toward the rim, so they are called caliper brakes. A caliper brake uses a single assembly to move both brake shoes together, unlike a cantilever brake which has a separate unit on each side of the rim.

A brake caliper attaches to the bicycle by a single bolt, through the center of the fork crown or the brake bridge on the seat stays.

Some internal gear hubs use cams to change the engagement of pawls, to select different gear ratios.

See also rollercam brake.

Campagnolo parts are so highly regarded that Campagnolo's proprietary dimensions have, in several cases, become adopted as de facto international standards. This is particularly so in the case of headsets.

The Campagnolo headset dimensions are 26.4 mm for the fork crown race and 30.2mm for fitting the frame races into the head tube. Other common systems, such as J.I.S., use a larger diameter (such as 27 mm) for the steerer, and a smallaer diameter (30 mm) for the head tube. These frame/fork dimensions can be easily machined to fit Campagnolo style headsets.

Campagnolo links:

• Campagnolo Catalogues
• Campy Only
• Tutto Campagnolo
• Vélo-Rétro Campagnolo Timeline page.

A recent variation on cantilever brakes is the V brake which dispenses with the transverse cable altogether.

For front derailers, when the derailer is mounted high enough to clear the largest chainwheel, there is a certain minimum size that you need for the smallest ring so that the chain won't be dragging over the bottom of the front cages. Different front derailers have different capacities depending on how tall their cages are. It is expressed in a number of teeth, which is the difference between the largest and smallest chainwheel. For instance, a 52/42/30 crank set would call for a front derailer with a minimum 22 tooth (52-30) capacity.

Front derailers are also designed to be used with a certain size for the largest chain ring. The curvature of the outer cage plate is matched to this size. If you use a different size big ring, capacity may be reduced. If the big ring is substantially smaller than the derailer is designed for, shifting precision will suffer. If the big ring is much smaller than the derailer is designed for, it may shift OK, but you are likely to have to "trim" the front derailer as you shift the rear derailer to the extremes.

For rear derailers, the capacity relates to the amount of chain slack the derailer can take up, and is equal to the front range (22 in the example above) plus the rear range. Thus, if you have a 52/42/30 crank set, and a 12-28 (16 tooth difference) cluster, the total capacity required would theoretically be 38 teeth (22 front difference + 16 rear difference).

Manufacturers specify this fairly conservatively. They must do so, because they have to assume that some of their derailers will be sold to incompetent cyclists, who will abuse their drive trains by using the smallest chainwheel with the smaller rear sprockets.

Competent riders can considerably exceed the official rated capacity, since they will not misuse the granny ring by running it with the smaller rear sprockets, so it doesn't matter if the chain hangs slack in those gears.

Rear derailers are also commonly designed for a particular maximum size rear sprocket. If you exceed this size, by too much, the jockey pulley may rub against the sprocket when using the lowest gear.

Rated maximum rear sprocket size, however, is also commonly much lower than what actually works. For instance, Shimano's models designated as "road" derailers are generally listed for a "maximum" sprocket of 27 teeth...because 27 teeth is the largest size that they make in a designated "road" cassette. However, in almost all cases, these derailers, even the short-cage models, will handle rear sprockets as large as 30 teeth in practice. (This somewhat depends on the design of the frame's derailer hanger, so once in a while you will find a particular installation where you can't use a 30, but I've never seen one where a 28 wouldn't work.

I'll also mention that many folks seem to be a bit mystified and intimidated by derailers. They're actually quite inexpensive and easy to replace, so it is foolish to allow the limitations of a particular derailer to keep you from having the gearing appropriate to your riding style/needs.

See the Wikipedia article on Screws for more details on this.

Bearings which are assembled in a modular unit, as opposed to cup-and-cone bearings, which may be disassembled down to the individual bearing balls for service.

Cartridge bearings are the only type of ball bearings used in most industrial products; bicycle technology is the major area where cup-and-cone bearings still survive, but they are in decline even in the bicycle industry. *******

A conventional cup-and-cone bottom bracket. The lock ring wrench is about to loosen the lockring, the pin wrench is engaging two of the holes in the adjustable cup

A cartridge bottom bracket. The splined tool is shown above the bottom bracket. The crank would need to be removed to actually use the tool.

If you're speaking generically about multiple rear sprocket sets, or in other situations where you don't know which type is on a particular bike, the safest generic term is "cluster" which can apply equally to freewheels and cassettes.

Cassette Joint Shimano internal gear hubs with more than three speeds connect the shift cable to the hub by the use of a "cassette joint", which is a pulley mechanism that fits around the axle, just outboard of the sprocket (but inboard of the bicycle's frame.) For details on this, see my Nexus Technical Page.

Cassette Joint

Cassette Joint

An exotic form of casting, called investment casting or "lost wax" casting permits casting of complicated shapes by using single-use plaster moulds that can be broken apart to free the cast part from the mould. This is an expensive process used mainly for high quality lugs and fork crowns.

See also Jeff del Papa's article on Forging, Casting & CNC Machining on this site.

In the case of measuring bicycle frames, all measurements are assumed to be center-to-center except for the seat tube length.

Seat tubes are sometimes measured from the center of the bottom bracket, but the upper end point may vary depending on the measurement system choesn. Center-to-center seat tube measuremnents measure to the intersection of the center of the top tube with the center of the seat tube.

See also the entry on "Frame Size. "