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Sheldon Brown's Bicycle Glossary Ha-Hi

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Obsolete type of helmet, consisting of a network of stuffed leather straps.

Half-radial Spoking

This refers to a wheel which is radially spoked on one flange, semi-tangent on the other.

For an explanation of this design, see my wheelbuilding article.

Half-step Gearing

In the days of 4- and 5-speed freewheels, 8- and 10-speed bikes were commonly set up with chainwheels that were very close in size, for instance, 46/49, or 47/50. When used with typical freewheels of the era, the difference between the two front gears was about half as large as the difference between adjacent gears on the freewheel. (One reason for this was that early front derailers couldn't handle much more than a 3-tooth difference reliably!)

With half-step gearing, the larger shifts are made with the rear derailer, and the front is for fine tuning. This allows an 8- or 10-speed set up to have a reasonable range with fairly close spacing of the gears. One downside of half-step is that it uses all possible combinations, including those that run the chain at a fairly severe angle. This is not a big deal in an 8-speed rig, but is kind of marginal for 10-speeds. Another serious disadvantage is that every other shift in the normal sequence is a double shift (front and rear derailers simultaneously).

Half-step gearing is most suitable for riding in flat terrain, where shifting is rare. For bicycles with few speeds, it does allow finer gradations to get as close to the "ideal" gear for the particular wind conditions as possible.

Modern shift patterns use larger jumps on the chainwheels to select general ranges of gears, and fairly closely-spaced 7-or-more-speed clusters for the fine tuning. This greatly simplifies the shifting pattern, allowing constant adjustment to different grades in rolling terrain, with only occasional need for double shift.

See my Article on Gear Theory .


"Handle bars" on early bicycles were actually bars of solid steel. Solid handlebars became obsolete before the end of the 19th century; all modern handle "bars" are actually tubular, but the name persists.

Conventional handlebars are divided broadly into two styles: "drop" and "upright"

See also Hands Up! Adjusting Handlebar Height

Handlebar dimensions
Stem Clamp
Grip Area
22.2 mm7/8"22.2 mm7/8"Steel bars. Mainly BMX, older Mountain bike bars.
23.8 mm15/16"22.2 mm7/8"Obsolete British size for steel handlebars, common on older 3-speeds.
This size was also used for older British steel drop bars.
25 mm23.5 mmObsolete French size.
25.4 mm1"22.2 mm7/8"Standard I.S.O. size, used on the vast majority of newer bicycles with upright handlebars.
This size was formerly common for steel drop bars.
25.4 mm1"23.8 mm15/16"Standard I.S.O. size, used on most bicycles with drop handlebars.
Also used on older British aluminium upright handlebars.
25.8 mm23.8 mm15/16"Unofficial in-between size used by some Italian handlebar makers for handlebars designed to be usable in either ISO (25.4) or Italian (26.0) size stems.
26.0 mm23.8 mm15/16"Italian standard for drop bars, other bars made to fit Italian stems and some high-end aftermarket drop bars.
This is sometimes incorrectly called "road" size.
26.4 mm23.8 mm15/16"Older Cinelli and Cinelli copies. Cinelli changed over to 26.0 mm in 1998.
27 mm23.8 mm15/16"Titan (obsolete).
31.8 mm1 1/4"23.8 mm15/16"Road oversized.

Handlebar Grip

Handlebar Stem

See stem

Handlebar Tape

Cloth or plastic or leather tape that is wrapped around handlebars to provide better grip and some cushioning. Most commonly used on drop handlebars.

Sometimes incorrectly referred to as "handlebar ribbon." This mistake results from a translation error. (in French and Italian, there is no distinction between "ribbon" and "tape.")


This term has several bicycle applications:


A motorcycle term for a bike which has no rear suspension. Some cyclists find this term offensive when applied to bicycles.


Steel can be made to have different characteristics by various heat treating processes. These involve heating steel to various temperatures then cooling it down either rapidly or gradually. Depending on the specific heat treatment chosen, steel may be either very hard and brittle or soft and flexible.

This is a very complicated technology, with very ancient roots. For many applications, such as sprockets and bearings you want a very hard surface to the part, but the inside of the part should be treated to a lesser hardness so as to avoid excessive brittleness and breakage.

Hard Anodized

See: Anodized


The bearing assembly that connects the front fork to the frame, and permits the fork to turn for steering and balancing.

A conventional threaded headset consists of four races plus associated parts:

  1. The crown race, which is pressed on to the bottom of the steerer, just above the crown.
  2. The lower head race is pressed into the bottom of the head tube.
  3. The upper head race is pressed into the top of the head tube.
  4. The adjustable race attaches to the steerer.

    The adjustable race is secured by either a:

Threaded vs Threadless

There are two different systems for attaching and adjusting the adjustable race:

Threaded Headset

Note wrench flats on locknut and top threaded race.
Threaded Headset

Threadless Headset

Note pinch bolts on stem.
Threadless Headset

Headset sizing

The nominal size of a headset is based on the outside diameter of the steerer. This is a source of confusion, because the steerer is not visible on an assembled bicycle. In the case of a bicycle with a traditional expander/wedge type stem, the stem shaft will be 1/8" smaller than the steerer. Sometimes people measure the stem diameter and assume, incorrectly, that this is the size headset they have.

Threaded Headsets
Steerer O.D.
Stem diameter
Steerer I.D.
Crown race
Inside diameter
Frame Cup
Outside Diameter
Per inch
BMX/ O.P.C. bikes.833"
(21.15 mm)
26.4 mm32.7 mm24Used mainly on bicycles with one-piece cranks, also some early mountain bikes.
French 25 mm 22 mm26.5 mm,
27.0 mm
30.2 mm25.4
(1 mm)
Obsolete. French steerers usually have a flat filed on the back, rather than a grooved keyway as with other threaded systems.Interchangeability note:

These 5 sizes of forks
and headsets
all fit the same frames,

since the head tube
size is the same.

1" ISO Standard
(25.4 mm)
7/8"(22.2 mm)26.4 mm30.2 mm24This is the standard 1" size.
1" Italian (25.4 mm)7/8"(22.2 mm)26.5 mm,
27.0 mm
30.2 mm24Obsolete. Threads are cut at 55 degrees, but ISO or J.I.S. headsets can be used.
1" J.I.S.
(25.4 mm)
7/8"(22.2 mm)27.0 mm30.0 mm24Older or lower-quality bicycles from Asia
1" Raleigh
(25.4 mm)
7/8"(22.2 mm)26.4 mm30.2 mm26Proprietary size used on Raleighs made in Nottingham, England
(26 mm)
22 mm26.7 mm30.8 mm25.4
(1 mm)
Higher quality Austrian bikes use English/ISO
French Tandem 28 mm 22 mm 25.4
(1 mm)
Obsolete and rare.
1 1/8" (28.6 mm)1" (25.4 mm)30.0 mm34.0 mm26"Oversized" (This size is more often used for threadless systems.)
1 1/4" (31.8 mm)1 1/8" (28.6 mm)33.0 mm37.0 mm26Mainly used on tandems

Threadless Headsets
Size/Stem diameter
Steerer O.D.
Crown race
Inside diameter
Frame Cup
Outside Diameter
BMX/26.4 mm32.7 mmUsed mainly on bicycles with one-piece cranks.
1" ISO Standard (25.4 mm)26.4 mm30.2 mmThis is the standard 1" size.
1 1/8" (28.6 mm)30.0 mm34.0 mmMost newer mountain bikes use this size.
1 1/4" (31.8 mm)33.0 mm37.0 mmMainly used on tandems
1.5" (38.1 mm)39.8 mm49.6 mmProposed OnePointFive standard for downhill and freeride applications.

If you want to replace one headset with another, you must take into account the stack height of the new headset.

See also my article on Headsets

See also Hands Up! Adjusting Handlebar Height

Head Tube

The front tube of the frame, through which the steerer passes. The length of the head tube gives a quick visual indication of frame size, because it varies more, proportionally, with frame size than any of the other tubes.

Helicomatic ®


The Maillard Helicomatic hub was an early version of a cassette freehub. They came with a cute little pocket-size tool that incorporated a spline wrench for the cassette lockring, a spoke wrench, and a bottle opener. The Helicomatic was a nice idea on paper, but poorly executed. These hubs are losers.

Both hub flanges were 1mm farther to the left than those of a normal hub, causing increased dish in the rear wheel, and persistent spoke breaage problems. Many loyal Helicomatic fans tout the ease with which the cassette may be removed for spoke replacement as a great virtue, but if the hub were better designed, it wouldn't break so many spokes!

These hubs were prone to bearing problems as well. Due to clearance requirements, they couldn't fit the normal 9 1/4" bearing balls, so they used 13 5/32 balls on the right side. These didn't hold up well. The cones tended to wear rapidly, and replacement cones are no longer available to fit these hubs.

Hellenic Stays

A frame design in which the seat stays don't go to the seat cluster, but rather cross outside of the seat tube a few inches below the seat cluster, then go on to be attached to the top tube a few inches forward of the seat tube.

Hellenic stays were introduced by (and named for) the British frame builder Fred Hellens in 1923, and have been used off-and-on since by frame builders who wish to make their frames visually distinctive. It is of no practical value, and often causes un-necessary complication to brake cable routing, luggage rack attachment and installation of frame pumps. It is also slightly heavier than normal frame construction.

Recent users of this design include GT, Huffy and Nashbar.



Dan Henry Arrow

Dan Henry was a very influential cyclist in the '50s and '60s. He is most famous for the "Dan Henry Arrow" an arrow painted on the roadway with a stencil or a spray can, as a way of giving directions for organized rides. Many recreational bike clubs use Dan Henry Arrows to mark their recommended routes.

He also did a lot of pioneering work on suspension designs for bicycles, and deveoped a bicycle seat that was based on an upside-down dropped handlebar with furniture webbing wrapped between the two straight sections.

He was also known for roller demonstrations where he would perform a strip-tease while riding on the rollers. A very cool guy.


High flange (hub)

High (Gear)

A high gear is one in which the pedals move slowly compared to the speed of the wheels. High gears are achieved by using large chainwheels and small rear sprockets.

High gears are for going fast, when the terrain permits. The rider must push much harder on the pedals in a high gear, so high gears are not suitable for lower-speed riding, due to the great strain that hard, slow pedaling puts on the joints.

High Flange Hubs

See "flange."


See "Low-normal."

High Riser

Wheelie bike.

High tensile, high tension, Hi-Ten

A fancy-sounding name for the ordinary tubing used to build cheap bicycle frames.

High Wheeler

The second-oldest style of bicycle, the successor to the "bone shaker," and the predecessor of the modern "safety" bicycle."

Before the use of chain drive, bicycles had direct drive. The cranks were directly attached to the hub of the drive wheel. The larger the wheel, the farther the bicycle would move with each turn of the pedals. The diameter of the drive wheel determined the gear of the bicycle. The larger the wheel, the higher the gear.

With a chain-driven "safety" bicycle, you can have any gear you want by selecting appropriate sprockets. With a high-wheel bicycle, the limiting factor is how long your legs are, because you can only pedal a wheel that is small enough for your legs to straddle and reach the pedals throughout the pedal revolution.

The safety bike was first introduced on a commercial scale in 1885, and by 1893 high-wheelers were out of production.


A spring device which attaches to the seatpost and to a quick-release seatpost bolt. It allows the rider to adjust the saddle height while riding. This was a fashionable option in the early days of mountain biking, but is no longer popular.

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Since May 4, 1996

Copyright © 1996, 2008 Sheldon Brown

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