Gage
Gain ratio
For more detail on gain ratios, see my article on the subject.
You can calculate gain ratios., gear inches or meters development. with my Online Gear Calculator or with your slide rule
Gas Pipe
Gauge
- A measurement of thickness, particularly of wire. The major use of gauges in bicycle technology is for spokes. There are several different national systems of gauge sizes, and this has been a great cause of confusion. A particular problem is that French gauge numbers are smaller for thinner wires, while the U.S./British gauge numbers are larger for thinner wires. The crossover point is right in the popular range of sizes used for bicycle spokes:
U.S./British 14 gauge is the same as French 13 gauge
Newer I.S.O. practice is to ignore gauge numbers, and refer to spokes by their diameter in millimeters, usually rounded to the nearest tenth of a millimeter.:
U.S./British 13 gauge is the same as French 15 gaugeU.S./British 13 gauge is 2.3 mm
The gauge system is basically obsolete as explained in this excerpt from "Machinery's Handbook" 21st edition, 1980 p463:
U.S./British 14 gauge is 2.0 mm
U.S./British 15 gauge is 1.8 mm
U.S./British 16 gauge is 1.6 mm
U.S./British 17 gauge is 1.4 mm
WIRE AND SHEET METAL GAGES
The U.S. system, S.W.G. and Birmingham gages are all the same for 15 gage, 0.72" (1.8288 mm.)The thickness of sheet metals and the diameters of wires conform to various gaging systems. These gage sizes are indicated by numbers and the following tables give the decimal equivalents of the different gage numbers.Much confusion has resulted from the use of gage numbers and in ordering materials it is preferable to give the exact dimensions in decimal fractions of an inch... [millimeters preferred nowadays-SB ]
...the decimal method of indicating wire diameters ...has the advantage of being self-explanatory, whereas arbtrary gage numbers are not. The decimal system of indicating gage sizes is now being used quite generaly, and gage numbers are gradually being discarded. Unfortunately there is is considerable vaiation in the use fo different gages. For example a gage commonly used for copper, brass and other non-ferrous metals may at times be used for steel, and vice versa...
The wire gage system used by practically all the steel producers in the United States is known by the name Steel Wire Gage or to distinguish if from the Standard Wire Gage (S.W.G.) used in Great Britain it is called he United States Stee Wire Gage. It is the same as te Washburn and Moen, American Steel and Wire Company, and Roebling Wire Gages. The name has the official sanction o fthe Bureau of Standards at Washington, but is not legally effective. The only gage which has been recognized in Acts of Congress is the Birmingham Gage...the Birmingham Gage is, however, nearly obsolete both in the United States and in Great Britain, where it originated...
In Great Britain one wire gage has been legalized. This is called the Standard Wire Gage (S.W.G.), formerly called Imperial Wire Gage.
Below is a small excerpt from the table referred to:
Gage
NumberU.S. Steel Wire Gage British S.W.G. Birmingham Gage 12 .1055" 2.6797 mm .1040" 2.6416 mm .1090" 2.7686 mm 13 .0915" 2.3241 mm .0920" 2.3368 mm .0950" 2.413 mm 14 .0800" 2.032 mm .0800" 2.032 mm .0830" 2.10 mm 15 .072" 1.8288 mm .072" 1.8288 mm .072" 1.8288 mm 16 .0625" 1.5875 mm .0640" 1.6256 mm .0650" 1.651 mm 17 .0540" 1.3716 mm .0560" 1.4224 mm .0580" 1.4732 mm - A measuring instrument, most commonly in bicycle contexts, a device for measuring the air pressure in a tire.
Gear
The gear of a bicycle depends on the ratio between the sizes of the front and rear sprockets, and the size of the drive wheel. If the bicycle is equipped with planetary gears, they also affect the gear. There are several ways of designating gears numerically. See gain ratios, gear inches, and development.
For information on using your bicycle's gears, see my article: Everything You Wanted to Know About Shifting Your Bicycle's Gears, But Were Afraid to Ask
Gear Inches
See also gain ratios and development.
You can calculate gear inches, gain ratios, or meters development. with my Online Gear Calculator or with your slide rule
Gear Case
Chain replacement with a gear case:
- You will need to remove the disc that covers the chainwheel. Pry it with a flat-blade screwdriver, as with the lid of a paint can.
- Remove the pieces at the back by undoing the obvious screws.
That's as far apart as it needs to come for chain replacement.
It's very helpful if you have a proper work stand that lets you tilt the bike up and down, but if you don't, a strong friend can handle the bike for you.
- Set the bike vertical with the front end downward, drop one end of the chain into the upper section of the chaincase until you can thread the end of the chain onto the chainring.
- Once the end of the chain has engaged the chainring, pivot the bike vertically so that it's facing straight up. Turn the cranks forward to feed the end of the chain through the lower run of the chain case until the end appears at the rear opening.
- Join the chain, either with the master link or with a chain tool an put it all back together.
Gel
Gel has been rather over hyped as a cure-all for saddle related discomfort.
Generator
Unfortunately, the output of a generator is dependant on the bicycle's speed. They produce no light when stopped, little at low speeds. Fast riding can cause the voltage to rise to the point that bulbs burn out prematurely.
The widespread availability of re-chargeable batteries has considerably reduced the desirability of generator powered systems. The vast majority of bicycle generator systems only put out 3 watts; a very few put out 6 watts (when running at optimal speed.) Since rechargeable systems commonly put out 15 watts or more, at all speeds, they are generaly preferable for most applications.
- "Bottle" generators, the most common type, are shaped like a bottle, with a small wheel at the "cap" which rubs against the side-wall of the tire.
- "Bottom-bracket" generators mount below the chainstays, and have a spring-loaded roller which presses against the tread of the tire. Bottom bracket and bottle generators frequently slip and fail when ridden in wet conditions.
- Hub generators are built into one of the wheel hubs. They usually consist of a stationary armature (coil) attached to the axle, with a revolving multi-pole ring-shaped magnet surrounding the armature. The best-known of these is the no longer avaialble Sturmey-Archer Dynohub.
Hub generators were unavailable for several years, but they are undergoing something of a renaissance in this century, with models from Busch & Müller, Shimano (Nexus ) and Sturmey-Archer.
Hub generators are more expensive than other types, but they are more efficient, more reliable and silent.
Ghost Shifting
Gizzmo ®
Gloves
Traditional cycling gloves are fingerless, with leather palms, often double layered with a foam sandwich under the heel of the hand. The backs were traditionally a crocheted mesh, though Lycra ® is more common of late.
Goofy Footed
If you coast with your right foot forward, that's sometimes called "goofy footed" and can contribute to loosening up or damaging the crank, since it applies stress in the opposite direction than the stresses of normal pedaling.
This term comes from the world of surfing, where left-foot forward is the norm.
Goose Neck
Granny Gear
Note that this term is not a general term for the lowest gear of a bicycle, but specifically refers to just the smallest chainwheel on a crankset with more than two chainwheels.
Grease
There are a great many different greases on the market with different special features, mainly for automotive applications. For bicycle use, almost any grease is adequate, since the loads and temperatures are generally low.
An exception is coaster brakes, which need a heat-resistant grease.
Greaseguard ®
GripShift ®
Group
A group would normally include (as a minimum) the following:
- Hubs
- Bottom bracket
- Derailers
- Shifters
- Brakes
If the manufacture offers them, a group could also include:
- Pedals
- Headset
- Seat post
Grouppo
Goupset, Group Set
Gruppo
Gum
Gusset
Gyro ®
In addition, the Gyro has a ball-bearing built into it, so it has very little friction while turning.
Gyro adjustment:
Every part in a brake system has a certain amount of "travel" available. For instance, the lever can go from its rest position (which is often adjustable for hand size by a small screw) as you squeeze it to the point where the lever bumps into the handlebar grip.The caliper has a limited amount of travel too, limited by the brake shoes hitting the rim on the inward side, and by whatever stops the arms from springing out when the brake is released.
On any braking system, the outward (rest position) travel should be limited by the lever bumping against its stop, but the inward travel should be limited only by the brake shoes hitting the rim. You should be able to squeeze the lever as hard as you can without having the lever bump into the grip, because once the lever bottoms out no more braking power is transmitted to the brake shoes, no matter how much harder you squeeze.
The Gyro has a limited amount of travel available to it also, and it is important to ensure that the Gyro itself is not the limiting factor in either inward or outward travel.
Start by hooking up the upper cable between the lever and the Gyro. Operate the lever with one hand whilst pulling downward on the Gyro assembly. The adjusting barrels on the Gyro (and on the lever, if there is one) should be set so that the lever just barely stops the Gyro from bottoming out against the headset when you release the lever.
Make sure that the adjusting barrels on both sides are set the same way, so that the Gyro is horizontal. Otherwise, the braking action may vary as you turn the handlebars.
Once the upper cable is set, connect the lower cable to the brake in the usual manner.
