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
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.
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.
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.
If you wish to determine the date of manufacture of a Campagnolo part, see the 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).
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.
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.
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. |
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.
Chain size is specified by pitch and width. The pitch is the distance between rollers (1/2" on all modern bicycle chain). The width is the internal width where the sprocket teeth fit in. Bicycle chain comes in two basic widths:
Chains for derailer applications also come in various external widths. Newer clusters which have more sprockets use chain with thinner side plates and flush rivets.
For more information on chains, see my article on Chain Maintenance.
In the case of derailer geared bicycles, the chainline is not perfect in most gears. The worse the chainline, the worse the mechanical efficienty of the drive train.
"Correct" chainline for a derailer system is a matter of opinion, and depends on the intended use of the bicycle. There are two "simple" answers to the question of what constitutes proper chainline:
Chainline is measured from the centerline of the frame to the center of the chain.You can measure the front chainline directly with a simple ruler. Simply hold the ruler against the seat tube or down tube and measure the distance to the middle of the chainring teeth. In the case of triple chainwheel sets, measure to the middle chainring. In the case of doubles, measure to the halfway point between the two rings.
To measure rear chainline, the easiest way is to measure the distance from the inside of the rear fork end (or the outside of the axle locknut) to the middle of the sprocket. Double this, subtract it from the over-lock-nut dimension of the hub (or the frame spacing , which should be the same), then divide the result in half, and you have the rear chainline.
| Application | Dimension | Notes |
|---|---|---|
| Road Double | 43.5 | Shimano spec, measured to the midpoint between the rings. with typical 5 mm chainring spacing, this puts the inner at 41 mm, the outer at 46 mm. |
| Road Triple | 45 | Shimano spec, measured to the middle ring. |
| MTB Triple | 47.5-50 mm | Shimano spec, measured to the middle ring. 47.5 preferred, but for frames with oversized seat tubes, the longer dimension may be needed, because the fat tube places the derailer mechanism farther to the right. |
| Track/Coaster Brake Traditional One-Speed Most internal gear hubs | 40.5-42 mm | Older bikes with 110 spacing would be on the smaller end of this range Newer bikes with 120 mm spacing normally use 42 mm |
| Singlespeed MTB | 52 mm | Wider chainline need for chainstay clearance on MTBs. This is close to the chainline of the outer ring of a typical MTB triple |
| Rohloff Speedhub | 54 mm (58 mm w/13 tooth) | |
| Singlespeed MTB Alternate | 47.5 mm | White Industries ENO hubs use this chainline, which lines up with the middle position of a typical MTB triple. It's also fairly close to the outer position of a typical "road" double. |
I have measured a selection of track sprockets, single freewheels and hubs with respect to chainline (units are millimeters.) The "Chainline" column is the distance from them mounting shoulder to the center line of the sprocket teeth.To figure the actual chainline for a given combination, add the number from the "chainline" column of the sprocket or freewheel to the corrresponding "chainline" column of the hub chosen.
(If you can provide dimensions for additional models, please
send the info to me!)
| Fixed (Track) Sprockets | |||||
|---|---|---|---|---|---|
| Model/Type | Nominal Width | Chainline
(From Shoulder) | Measured width | Total thickness | Thread Thickness |
| Campagnolo | 3/32" | 7.0 | 2.0 | 8.0 | 7.8 |
| Campagnolo | 1/8" | 6.5 | 3.0 | 8.0 | 7.2 |
| E.A.I. | 3/32" | 7.13 | 2.2 | 8.23 | 8.05 |
| E.A.I. | 1/8" | 6.73 | 3.02 | 8.24 | 8.05 |
| Miche Quick Change Splined | 3/32" | 5.85/5.15 | 1.9 | 7.72 | 7.3 |
| Miche Quick Change Splined | 1/8" | 5.85/5.15 | 3.0 | 7.72 | 7.3 |
| Phil Wood | 3/32" | 5.86 | 2.3 | 7.01 | 7.01 |
| Phil Wood | 1/8" | 6.05 | 3.02 | 7.56 | 7.06 |
| Shimano Dura-Ace | 3/32" | 6.49 | 2.11 | 7.55 | 7.55 |
| Shimano Dura-Ace | 1/8" | 7.05 | 3.05 | 8.58 | 7.7 |
| Sugino Gigas | 1/8" | 7.0 | 3.0 | 8.5 | 7.5 |
| Sun Tour Superbe | 3/32" | 6.22 | 2.26 | 7.35 | 7.35 |
| Sun Tour Superbe | 1/8" | 6.93 | 3.05 | 8.46 | 7.5 |
| Surly | 3/32 | 5.28 | 2.05 | 6.31 | 6.31 |
| Surly | 1/8" | 5.07 | 2.7 | 6.42 | 6.42 |
| Single Speed Freewheels | ||||
|---|---|---|---|---|
| Model/Type | Nominal Width | Chainline
(From Shoulder) | Measured width | Total thickness |
| ACS | 3/32" | 7.96 | 2.16 | 9.04 |
| Shimano | 3/32" | 7.89 | 2.08 | 8.92 |
| Shimano | 1/8" | 8.67 | 3.0 | 10.17 |
| Tristar | 1/8" | 7.71 | 2.96 | 9.19 |
| White Industries | 3/32" | 8.73 | 2.17 | 9.82 |
| Single Speed and Fixed Gear Hubs | |||||||
|---|---|---|---|---|---|---|---|
| Model/Type | Track/MTB | OLD Spacing | Adjustable?* | Chainline
Center to Shoulder | Left Side | Right Side | Drillings |
| Campagnolo small flange 2002 | Track | 120 | Yes | 36 | Plain | Fixed | 28, 32, 36 |
| Campagnolo C-Record Large flange | Track | 120 | Yes | 35.9 | Plain | Fixed | 28, 32, 36 |
| Gold Tec | Track | 120, 130, 135 | Yes | 39.5 | Fixed | Fixed | 32, 36 |
| Miche | Track | 120 | Yes | 36.3 | Plain | Fixed | 28, 32, 36 |
| On-One Full Monty | MTB | 135 | No | 43.3 | Plain | Free | 32, 36 |
| Phil Wood Track | Track | 120, 126, 130 | No | 36.75 | Plain/Fixed/Free | Fixed | 28, 32, 36 |
| Phil Wood K.I.S.S. Off | MTB | 135 | No | 45.35 | Plain/Free | Fixed/Free | 32, 36 |
| Shimano Dura-Ace 7700 | Track | 120 | Yes | 35.3 | Fixed | 28, 32, 36 | |
| Shimano Dura-Ace 7700 Small Flange | Track | 120 | Yes | 35.3 | Fixed | 28, 32, 36 | |
| Shimano Dura-Ace 7600 Large Flange | Track | 120 | Yes | 35.4 | Fixed | 28, 32, 36 | |
| Sovos | Track | 112 | Yes | 33.5 | Free | Fixed | 36 |
| Spot | MTB | 135 | No | 47.25 | Plain | Free | 28, 32, 36 |
| Surly Track | Track | 120 | Yes | 36.22 | Free | Fixed | 32 |
| Surly 1 x 1 | MTB | 135 | Yes | 46.5 | Free | Fixed/Free | Drillings |
| Suzue Basic | Track | 117-120 | Yes | 34.74 | Free | Fixed | 28, 32, 36 |
| Suzue Promax (cartridge) | Track | 120 | Yes | 35.0 | Free | Fixed | 28, 32, 36 |
| Suzue Promax NJS | Track | 120 | Yes | 35.0 | Fixed | Fixed | 28, 32, 36 |
| Van Dessell | MTB | 135 | No | 45.9 | Free | Fixed | 32 |
| White Industries ENO | Track/MTB | 126, 130, 135 | No | 39.1 | Free | Fixed | 28, 32, 36 |
Thanks to John Dacey and Marten Gerritsen for some of these data.
"Adjustable" means that the hubs use conventional threaded axles, so you can increase the OLD spacing by removing the locknuts and adding spacer washers. If you add equal thicknesses to both sides, the chainline is unaffected, since it's measured from the middle outward. If you add more spacers to one side, you can change the chainline, but if you do this with a double-sided hub, you will render it unusable on one side or the other, since you'll be increasing the chainline on one side while decreasing it on the other.
For information on interchangeability, see: Bolt Circle Diameter.
This jams the crankset. Since you probably wouldn't have been shifting to the granny if you weren't already climbing, the sudden lock-up of the drive train deprives you of what little momentum you had, and you are very likely to stall and fall.
Chain suck is commonly caused by bent chainring teeth, dirty chains, or, occasionally, burrs on the teeth of new chainwheels.
Jonathan Levy has an extensive Web site about Chain Suck
For information on interchangeability, see: Bolt Circle Diameter.
Tire/shoe
Ground/pedal*****
Up until the late '70's, cleats were leather or aluminum, and were nailed onto the bottom of the shoe with many tiny nails. The usual procedure was to have the cyclist ride for a while without the cleats, until the pedal would make a mark on the sole of the shoe. This mark would then be used as a guide to locate where the cleat should be nailed on.
In the '70's, adjustable plastic cleats were introduced, and immediately rendered the nail-on system obsolete...unfortunately, they also precipitated a rash of knee injuries, because riders would adjust them by pure guesswork, and this often caused un-natural stresses on their knees. The invention of the Fit-Kit R.A.D. made it possible to adjust this type of cleat even more accurately than the old sole-impression system.
Modern clipless pedals have solved these problems, and, in my opinion, nobody should still be using classic cleats. Now that there is an alternative, they are just not worth the risk.
A clincher tire has a separate inner tube, which is basically a rubber balloon. This fits inside the tire, and the tire is mounted on the rim by lifting the beads over the edge of the rim. The middle of the rim makes a sort of valley, and while the tire is being installed, most of the bead can fit into this valley. This gives enought slack to allow the bead to be pushed or pulled over the edge of the rim, even though outside diameter of the rim is larger than the inside diameter of the bead.
Strictly speaking, the term "clincher" is slightly incorrect, as it applied to an obsolete style of tire which had ribs in the edges of the tire which fitted into grooves on the rim, where the tire was folded under the tube. The air pressure in the tube pressed the rib into the groove, and "clinched" the tire in place. People who are fussy about this prefer the term "wire-on."
Other types of tires include airless tires, single-tubes (both obsolete) and tubulars.
"Clipless" or "Step-in" pedals use a mechanism similar to a ski binding. In fact the first successful system was made by a ski binding manufacturer, Look. Clipless pedals use a cleat which is bolted to the bottom of the shoe. When the rider steps on the pedal with the cleat, the cleat locks into the pedals mechanism, and is held firmly in place. Some systems hold the foot at a fixed angle, others allow various amounts of "float", or angular rotation of the foot on the pedal.
With most clipless pedal systems, the foot is disengaged by twisting the heel outward. Some of the earlier systems, such as the pioneering Cinelli model, required the rider to reach down and operate a release mechanism by hand. This style is sometimes jocularly referred to as "death cleats."
| Threaded Freewheel | Threaded Hub | Cassette Hub | Cassette Cluster |
|---|
| Accessories | Bicycles | Parts | Specials | Tools |
|---|
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