Bolt circle

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5hole wheel.png
4hole wheel.png
Drawing of 5-hole (left) and 4-hole (right) pitch circles

A bolt circle diameter or pitch circle diameter (PCD), sometimes simply called bolt circle or pitch circle, is a common term for when a number of screw holes for bolts are evenly distributed with their centers along an imaginary circle with a given diameter.

Contents

An example of use is mounting of car rims, where the bolt circle is one of several factors that determine whether a set of rims will fit a car. For example, a bolt circle of 5×130 or 5-130 indicates that a rim is to be attached to the car via 5 screws evenly spaced along a circle with a diameter of 130 millimeters. [1] Other common uses for bolt circles are for indicating mounting for sim racing and real-world car steering wheels, or in the industry for mounting of servomotors or for specifying the bolt pattern of a flange. Attachment of chain rings for bicycle cranksets are also specified by a bolt circle. [2]

Examples

Racing wheels

On steering wheels for cars utilizing bolt circles, this usually measures 6×70 mm. [3] Some racing wheels attach to the car via a quick release hub, [4] and this hub then usually has a corresponding bolt circle of 6×70 mm. Example of other less used patterns include: 3×1.75 in (44.45 mm), 5×2.75 in (69.85 mm), 6×74 mm and 6×2.75 in (69.85 mm). [3]

Servomotors

Industrial servomotors and gearboxes, with standardised flange mountings for interchangeability. 3417 09 Servogetriebe.jpg
Industrial servomotors and gearboxes, with standardised flange mountings for interchangeability.

Servomotors in the industry are often mounted via a flange-like coupling to give the shortest possible leverage for high-torque uses. Industrial servomotors often use standardised mounting patterns, of which one example is a bolt circle of 4×130 mm diameter (approximately corresponds to a square pattern of 91.9 mm × 91.9 mm).

Car rims

A bolt circle with four wheel nuts on an Acura. Lug-nuts.jpg
A bolt circle with four wheel nuts on an Acura.

The mounting pattern of most car rims are described using bolt patterns, and this pattern is one of many factors which determine whether a rim will fit a given car. Here, the bolt circle indicates the number of wheel nuts and associated hub bolts (or alternatively just wheel bolts). [5] [6]

An example of a bolt circle is 5×100 which indicates 5 nuts placed on a circle with a diameter of 100 mm. Some of the most common bolt circle diameters on modern cars are 100 mm, 112 mm and 114.3 mm.[ citation needed ] The bolt circle of a car is one of several parameters that must be checked before buying new rims to make sure they will fit the car (along with wheel offset, hub diameter, and finally the diameter and width of the rim and tire). Over the years, over 30 different bolt circles patterns have been used by car manufacturers, [7] most of which are not compatible with each other.

See also

Related Research Articles

A flange is a protruded ridge, lip or rim, either external or internal, that serves to increase strength ; for easy attachment/transfer of contact force with another object ; or for stabilizing and guiding the movements of a machine or its parts. Flanges are often attached using bolts in the pattern of a bolt circle.

<span class="mw-page-title-main">Spoke</span> Part of a wheel extending radially from the hub to the rim

A spoke is one of some number of rods radiating from the center of a wheel, connecting the hub with the round traction surface.

<span class="mw-page-title-main">Bicycle wheel</span> Wheel designed for a bicycle

A bicycle wheel is a wheel, most commonly a wire wheel, designed for a bicycle. A pair is often called a wheelset, especially in the context of ready built "off the shelf" performance-oriented wheels.

<span class="mw-page-title-main">Crankset</span> Bicycle part

The crankset or chainset is the component of a bicycle drivetrain that converts the reciprocating motion of the rider's legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. It consists of one or more sprockets, also called chainrings or chainwheels attached to the cranks, arms, or crankarms to which the pedals attach. It is connected to the rider by the pedals, to the bicycle frame by the bottom bracket, and to the rear sprocket, cassette or freewheel via the chain.

<span class="mw-page-title-main">Hubcap</span> Decorative disk on an automobile wheel that covers at least a central portion of the wheel

A hubcap or hub cap is a decorative disk on an automobile wheel that covers at minimum the central portion of the wheel, called the hub. An automobile hubcap is used to cover the wheel hub and the wheel fasteners to reduce the accumulation of dirt and moisture. It also has the function of decorating the car.

<span class="mw-page-title-main">Steering wheel</span> Type of steering control in vehicles and vessels (ships and boats)

A steering wheel is a type of steering control in vehicles.

<span class="mw-page-title-main">Wheel sizing</span> Measuring a wheel rim diameter to find the wheels size

The wheel size for a motor vehicle or similar wheel has a number of parameters.

<span class="mw-page-title-main">Wheelbuilding</span> Process of assembling wire wheels

Wheelbuilding is the process of assembling wire wheels. The components of a wire wheel are the rim, spokes, nipples, and hub.

<span class="mw-page-title-main">Cogset</span> Set of sprockets attached to the rear wheel hub of a bicycle

On a bicycle, the cassette or cluster is the set of multiple sprockets that attaches to the hub on the rear wheel. A cogset works with a rear derailleur to provide multiple gear ratios to the rider. Cassettes come in two varieties, freewheels or cassettes, of which cassettes are a newer development. Although cassettes and freewheels perform the same function and look almost the same when installed, they have important mechanical differences and are not interchangeable.

<span class="mw-page-title-main">Rim (wheel)</span> Outer part of a wheel on which the tire is mounted

The rim is the "outer edge of a wheel, holding the tire". It makes up the outer circular design of the wheel on which the inside edge of the tire is mounted on vehicles such as automobiles. For example, on a bicycle wheel the rim is a large hoop attached to the outer ends of the spokes of the wheel that holds the tire and tube. In cross-section, the rim is deep in the center and shallow at the outer edges, thus forming a "U" shape that supports the bead of the tire casing.

<span class="mw-page-title-main">Lug nut</span> Fastener, specifically a nut, used to secure a wheel on a vehicle

A lug nut or wheel nut is a fastener, specifically a nut, used to secure a wheel on a vehicle. Typically, lug nuts are found on automobiles, trucks (lorries), and other large vehicles using rubber tires.

<span class="mw-page-title-main">Wire wheel</span> Wheels whose rims connect to their hubs by wire spokes

Wire wheels, wire-spoked wheels, tension-spoked wheels, or "suspension" wheels are wheels whose rims connect to their hubs by wire spokes. Although these wires are considerably stiffer than a similar diameter wire rope, they function mechanically the same as tensioned flexible wires, keeping the rim true while supporting applied loads. The term suspension wheel should not be confused with vehicle suspension.

The ISO metric screw thread is the most commonly used type of general-purpose screw thread worldwide. They were one of the first international standards agreed when the International Organization for Standardization (ISO) was set up in 1947.

<span class="mw-page-title-main">Wheel stud</span>

Wheel studs are the threaded fasteners that hold on the wheels of many automobiles. They are semi-permanently mounted directly to the vehicle hub, usually through the brake drum or brake disk. Lug nuts are fastened onto the wheel stud to secure the wheel. When a wheel is removed for tire changes etc., the stud remains in the hub.

<span class="mw-page-title-main">Railway tire</span>

The steel wheel of a steam locomotive and other older types of rolling stock were usually fitted with a steel tire or tyre to provide a replaceable wearing element on a costly wheel.

<span class="mw-page-title-main">Screw</span> Type of fastener characterized by a thread wrapped around a cylinder core

A screw is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to the head. The most common uses of screws are to hold objects together and there are many forms for a variety of materials. Screws might be inserted into holes in assembled parts or a screw may form its own thread. The difference between a screw and a bolt is that the latter is designed to be tightened or released by torquing a nut.

<span class="mw-page-title-main">Tetrix Robotics Kit</span>

TETRIX Robotics consists of two robotic kits by Pitsco Education. The two sets are the TETRIX MAX building system and the TETRIX PRIME building system. They are intended to be used as educational robotics and for competitions such as the FIRST Tech Challenge.

A centerlock wheel is a type of automobile wheel in which the wheel is fastened to the axle using a single, central nut, instead of the more common ring of 4 or 5 lug nuts or bolts.

A direct-drive simulator steering wheel is a simulator steering wheel with a direct-drive mechanism between the drive and output, i.e. without gearing, and is used similarly as with other simulator steering wheels for providing torque feedback so that the driver, through movement in the steering wheel, gets an interface for sensing what is happening to the car in the simulator. It is an example of human–computer interaction in driving simulators, racing simulators, and racing video games, and is an example of haptic technology

References

  1. "Wheel Tech: Bolt Pattern".
  2. Wolf Tooth Tech Help - Measure Bike Chainring BCD Bolt Circle Diameter – Wolf Tooth Components
  3. 1 2 Steering Wheel Bolt Patterns Explained
  4. Quick release hub steering wheel | Raptor Steering Wheels
  5. "Bolt Circle Diameter (B.C.D.)" . Retrieved 3 December 2010.
  6. "P.C.D." Retrieved 4 December 2010.
  7. Boltsirkel.no