Wheelbuilding

Wheelbuilding

Wheelbuilding is the art and science of assembling a wheel (generally a bicycle wheel, although such wheels are also used on wheelchairs, motorcycles, and some cars, and known as wire wheels) from its component rim, spokes, nipples and hub.

Goals

A good wheelwright will ensure that the wheel is "true" in two ways: "lateral" (sideways wobble) and "radial" (roundness). Ideally spokes have similar tension (although the two sides will be different if a wheel is dished [dished: the uneven bracing angle of spokes on some multi speed wheels] ) with tension high enough to give a rigid wheel and retain some tension under all loads but not so high as to lead to failure of spokes or the rim. Spokes should have no residual twist (windup) from tightening the nipples. The spokes may be "stress relieved", i.e. subjected to a greater tension during building than they are ever likely to encounter in use - usually by squeezing pairs of spokes together very hard. This is said to yield the spokes (and/or the hub) into a permanent shape where they bend around the hub flanges and each other.

poking

Spoking patterns may be or semi-tangential. For a normal wheel size and spoke count, only the latter is suitable for a wheel that has to transmit torque from the hub to the rim, as with rear wheels or hub brakes. This rule is occasionally broken where a very large number of spokes is used or the wheel is unusually small in diameter, either of which reduce the amount of bending stress on each radial spoke to an acceptable degree; some BMX bicycles and low-riders use radial spoking for both wheels. Rear wheels may also incorporate radial spoking on the non-drive side and semi-tangential spoking on the drive side. The most common spoking pattern is "three-cross" where each spoke crosses three others on the same flange of the hub before meeting the rim. The last cross is normally "interlaced" by wrapping the spoke around the one from the other side of the flange. Radial-spoked wheels, where the spokes do not cross each other, saves roughly the weight of two spokes (because the spokes are shorter) compared to a three-cross wheel but run the risk of tearing hub flanges apart, unless the hub is specifically designed for this pattern. Two-cross is sometimes used for hubs with large-diameter flanges (such as generator/dynamo hubs or large flange hubs), as it gives a more perpendicular spoke/rim angle, and four-cross is standard for spoke counts of 40 and above.

Bicycle wheels

Most conventional bicycle wheels now use 32 or 36 spokes front and rear, although the asymmetry of the rear wheel (to allow for the cluster of sprockets), and the additional weight it carries, means it benefits from having more spokes than the front. Commonly used models vary from 18 spokes for racing bikes to 36 for cross-country touring bikes to 48 spokes on tandems and heavily abused BMX bikes. The minimum number of spokes allowed for competition is 12. [UCI Competition Rules - [http://www.uci.ch/english/about/wheels.htm] ] Some low-rider bicycles use as many as 144 brightly chromed spokes per wheel, although these are not meant for serious riding. Common rim diameters are 700c (sometimes 650c) for road/racing bikes, 27" or even 28" on older road bikes, 26" for most mountain bikes and 20" on BMXs and trials bikes. More recently a 24" wheel has found favour as a MTB/BMX cross for dirt jumping and street riding. 29" wheels are also gaining popularity for mountain bike trail riding.

Wheels can be built by machine instead of by hand. However, machine-built wheels are rarely as satisfactory as handbuilt wheels, partly because it is uneconomic to allow the machine to spend long enough on each wheel for a perfect result but also because most machines leave spokes with some residual twist. Machine-built wheels can be identified by their lacing pattern (if it is not radial), as the spokes are laced the same on each side, rather than mirrored as on hand-built wheels. More modern "factory built" wheels such as Mavic's Ksyrium series are of quite different construction from that of a conventional wheel, trading a deeper and stronger rim for fewer spokes. They are popular, being aerodynamic and quite light (in the more expensive models) but not as durable, readily repairable or maintainable as a conventional wheel.

Stainless steel is the most common material for spokes, although most mass-produced budget wheels use galvanized steel spokes. Other materials such as titanium, aluminum are often used to reduce weight. Some wheels are designed around carbon fiber spokes, which are often completely integrated with the hub and rim and bladed in shape. Non-steel spokes are normally reserved for racing bikes and other specialist applications where weight, aerodynamics and performance are valued over durability and cost. DT Swiss and Sapim (Belgium) are two of the most popular spoke brands used in hand built wheels.

Rims were traditionally made of steel but currently aluminum is by far most common and best choice due to its light weight, high durability and stiffness. Composite materials such as carbon fiber are sometimes used, typically for racing competitions such as time trial, triathlon and track cycling, although carbon fiber is becoming more common for recreational uses such as road cycling or mountain biking due to its light weight. Mavic (France), DT Swiss and Sun are popular makers of high quality bicycle rims.

The canonical text on building conventional bicycle wheels is "The Bicycle Wheel" by Jobst Brandt, published by Avocet.

Motorcycle wheels

Motorcycle wheels or wire wheels typically use 36 or 40 spokes, of much heavier gauge than those on a bicycle. They are never "interlaced" in the manner described above, nor are "radial" builds recommended (except on wheels without brakes, which are not themselves a good idea). Adequate spoke tension is very important with motorcycle wheels, because of the greater torque applied to the wheel by an engine or disc brake. Loose spokes on a wheel fatigue rapidly and break, usually at the bend where they attach to the hub. When this happens, the wheel must be rebuilt using all new spokes, because even unbroken spokes in such a wheel are fatigued, and will usually break when tightened during the truing operation.

poke length

The correct length of spokes required can be calculated using rim diameter, hub flange diameter, hub width, lacing pattern, and number of spokes. See [cite web | url=http://www.sheldonbrown.com/wheelbuild.html | title=Wheelbuilding | |last=Brown |first=Sheldon |authorlink=Sheldon Brown (bicycle mechanic) |publisher=Sheldon Brown | accessdate=2006-07-28] and. [cite web | url=http://www.geocities.com/spokeanwheel/index.html | title=Spoke Length Formula with Wheel Lacing and Building Information | author=Robert Torre | publisher=self-published | accessdate=2006-07-28] These calculations can be done either by hand (the old fashioned way - with a pen, paper and calculator) or by using a computer. There are many programs available and they range in complexity from simple Excel spreadsheets to stand alone desktop applications and web based calculators. An alternative method is to refer to a table which has the spoke lengths for a number of common hub and rim combinations.

Other conventions

A good wheelbuilder will ensure that the valve hole lies between two nearly parallel spokes to ease attachment of a pump head. This does not affect the structural integrity of the wheel, but it is unusual for this rule not to be observed.

It is also a convention, if the hub has a maker's label on its barrel, for the label to face (and be readable through) the valve hole. The rim labels should be readable from the right-hand side of the bicycle, as this is the side from which it is normally photographed. As the hub labels should face in the same direction front and rear (generally so they are readable from the seat), this means that even an undished, symmetrical front wheel has to be laced to the rim the "proper" way round, if perfection is the aim.

References

*The Bicycle Wheel by Jobst Brandt [http://www.avocet.com/wheelbook/wheelbook.html]
*The Art of Wheelbuilding by Gerd Schraner [http://www.dtswiss.com/Products/Proline/Buch-English.aspx]

ee also

*Bicycle mechanic
*Bicycle wheel
*Wire wheels


Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • Spoke — A spoke is one of some number of rods radiating from the center of a wheel (the hub where the axle connects), connecting the hub with the round traction surface. The term originally referred to portions of a log which had been split lengthwise… …   Wikipedia

  • Bicycle wheel — For the Marcel Duchamp installation, see Bicycle Wheel. The front wheel from a racing bicycle made using a Mavic rim …   Wikipedia

  • Wire wheels — Wire wheels, (wire spoked wheels), invented by James Starley, are still used on many motorcycles and most bicycles. Such wheels have a hub connected to a rim by wire spokes. Although these wires are generally stiffer than a typical braided wire… …   Wikipedia

  • Bottom bracket — A square taper cartridge bottom bracket. The bottom bracket on a bicycle connects the crankset to the bicycle and allows the crankset to rotate freely. It contains a spindle that the crankset attaches to, and the bearings that allow the spindle… …   Wikipedia

  • Sovereign Hill — is an Open air museum in Ballarat, Victoria, Australia, that depicts Ballarat s first ten years after the discovery of gold there in 1851. It was officially opened on 29 November 1970.Set in the Australian 1850s, the complex is located on a 25… …   Wikipedia

  • Wheelwright — A wheelwright (or wainwright) is a person who builds or repairs wheels. Making and balancing a wheel is skilled work.This occupational name eventually became the English surname Wheelwright .Historically, these tradesmen made wheels for carts and …   Wikipedia

  • Sturmey-Archer — are a manufacturing company originally from Nottingham, England. They primarily produce bicycle hub gears but have also produced motorcycle hubs. The company was founded in 1902 by Henry Sturmey and James Archer under the guidance of Frank Bowden …   Wikipedia

  • Holland Mechanics — is the world leader in wheelbuilding. The first wheel lacing machine was developed around 1963 by an external engineering company for Raleigh UK. The machine was tested but never put into action. After the labor union realized how many people… …   Wikipedia

  • Bicycle mechanic — A bicycle mechanic is a mechanic who can perform a wide range of repairs on bicycles. A person who works in a cycling store is usually only considered a bike mechanic if that person has experience repairing bikes. Bike mechanics can be employed… …   Wikipedia

  • Lace (disambiguation) — Lace is a lightweight fabric patterned with open holes.Lace may refer to:* Shoelace, a thin cord fitted to shoes to keep the shoes in placeIn Music: * Lace (band), a Canadian country music trio ** Lace (album), the Canadian country music trio s… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”