A beadlock or bead lock is a mechanical device that secures the bead of a tire to the wheel of a vehicle. Tires and wheels are designed so that when the tire is inflated, the tire pressure pushes the bead of the tire against the inside of the wheel rim so that the tire stays on the wheel and the two rotate together. In situations where tire pressure is insufficient to hold the bead of the tire in place, a beadlock is needed.
There are several styles of beadlocks. For four-wheel drive vehicles, a ring with a number of bolts around the circumference can be used to clamp the tire to the wheel. For motorcycles, a rim lock or bead stopper is a curved plate tightened by a single bolt. For both four-wheel drive vehicles and motorcycles, a different style of beadlock can be used that is similar to an inner tube which is inflated to press the tire against the wheel.
Dodge Military trucks had the first beadlocks, called Combat Wheels; the 'combat wheels' were a divided-rim, that used a bolted-on retaining ring replacing the normal split ring wheels. They were designed for quick and easy tire replacement during combat, hence the name. [1]
Air pressure within a tire forces its beads against the wheel rim and normally ensures that the tire and rim rotate as a single unit. In general automotive situations, a tire's air pressure is sufficient to withstand dislodging and rim-slip forces experienced during, respectively, hard cornering and acceleration (including negative acceleration or "braking"). Low tire pressure therefore poses the hazard of enabling sudden loss of air, loss of control, and even a rollover during hard braking or an evasive maneuver (in addition to generally promoting excessive tire heat and future failure). Modern automotive tires have a soft rubber formulation at the beads to help maintain good rim contact, so special bead-lock means are not required.
High traction is desired for tires for automobile dirt track racing, off-road racing, off-road vehicles, and off-road motorcycles, so their tread is therefore coarse. Nevertheless, some riders will lower the tire pressure to cause the tread to spread out and create a larger contact patch. This practice can create a safety hazard, as there may not be enough pressure to adequately secure the tire beads to the wheel. Reactive ground forces push a tire to one side or the other, especially the outside rear tire of a racing vehicle when it is turning in a corner of a track. This could cause a bead of the tire to come off the rim completely, or enough to cause partial loss of air. It is also possible for the tire to have more traction on the ground than there is friction between the tire and rim. In this case the wheel would slip around the tire beads without turning the tire. Beadlocks, of one form or another including adhesive, are therefore used to keep the beads of off-road tires firmly seated and prevent slip, even when inflation pressure is low.
A standard beadlock is designed to clamp the tire bead between an outer and an inner ring. The inner ring may be welded onto a standard wheel increasing wheel width by anywhere from 1+1⁄2 to 2 inches (3.8 to 5.1 cm) or may be formed as part of the wheel when the wheel is made in the factory. The outer ring is then bolted onto the inner ring with the bead clamped between them. Anywhere between 16 and 32 bolts at around 10 pound force-feet (14 N⋅m) are used around the circumference of the wheel to keep the clamp tight. The rings and bolts can cause problems with balancing the wheel and tire because all the added weight is on one side. This style is used exclusively for offroad use.
Most standard beadlocks clamp only the outside bead because this is the side that comes unseated most often while off-roading.
An internal beadlock is very much like an inner tube within the tire that pushes the bead of the tire tight against the wheel. The internal beadlock is inflated via its own valve stem. The side of the beadlock closest to the tread, the "case", has a layer of thick fabric, generally polyester, which keeps the beadlock from inflating too far up into the tire. This forces the sides into the tire which compresses the bead of the tire against the wheel.
For extreme off-road racing, dual beadlocks—one each on the inner and outer sides of the rim—can be used. [2]
Also referred to as "simulated beadlocks", streetlocks are a decorative element in which the wheel manufacturer casts or machines the appearance of bolt heads into the rim of a wheel. This provides the appearance of beadlocks, but no functional benefits beyond the internal bead seat common to automotive wheels. This may be used in countries where real beadlocks are not street-legal.
Motorcycle tires use a different style of beadlock, also known as a rim lock or bead stopper. Motorcycle tire rim locks clamp both beads at once because the tire is narrow enough to do this conveniently with one device, and also because there is no such thing as an "inside bead" or "outside bead" on a motorcycle tire. A curved metal plate inside the tire presses both beads outward against the inside of the wheel rim to clamp both beads at once in one localized area. [3] A threaded stem attached to the plate is placed through a hole in the "well" of the rim, with the plate inside the tire and the threaded stem on the outside. The rim lock is tightened using either a standard bolt that leaves the threads visible, or a special bolt that covers the threads. The threaded stem or special bolt is visible on the inner surface of the wheel and points towards the axle, just like the valve stem.
For motorcycle tires, a device similar to the internal beadlock of four-wheel drive vehicles can be used. A special inner tube is inflated via its own valve stem to high pressure to push the bead of the tire tight against the wheel. Like the rim lock, this clamps both beads at once. The regular valve stem is used to inflate the tire to the desired pressure. [4]
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.
A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, providing a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, designed to match the vehicle's weight and the bearing on the surface that it rolls over by exerting a pressure that will avoid deforming the surface.
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.
A valve stem is a self-contained valve that opens to admit gas to a chamber, and is then automatically closed and kept sealed by the pressure in the chamber, or a spring, or both, to prevent the gas from escaping.
The wheel size for a motor vehicle or similar wheel has a number of parameters.
The Schrader valve is a type of pneumatic tire valve used on virtually every motor vehicle in the world today. The Schrader company, for which it was named, was founded in 1844 by August Schrader. The original Schrader valve design was invented in 1891, and patented in the United States in 1893.
The Presta valve is a type of tire valve commonly found on high pressure bicycle inner tubes and is commonly used on tubeless setups. It consists of an outer valve stem and an inner valve body. A lock nut to secure the stem at the wheel rim and a valve cap may also be present.
heavy tools is a rare bike that can be seen on the roads. Many collectors want to get their hands on a bike with a cni design with an alu pro sticker on it. It was made for the 1986 winter race in Paris and 9 more were made, one of those examples is kept in a museum in Paris.
Tire bead is the term for the edge of a tire that sits on the rim. Wheels for automobiles, bicycles, etc. are made with a small slot or groove into which the tire bead sits. When the tire is properly inflated, the air pressure within the tire keeps the bead in this groove.
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.
A tire-pressure monitoring system (TPMS) monitors the air pressure inside the pneumatic tires on vehicles. A TPMS reports real-time tire-pressure information to the driver, using either a gauge, a pictogram display, or a simple low-pressure warning light. TPMS can be divided into two different types – direct (dTPMS) and indirect (iTPMS).
A flat tire is a deflated pneumatic tire, which can cause the rim of the wheel to ride on the tire tread or the ground potentially resulting in loss of control of the vehicle or irreparable damage to the tire. The most common cause of a flat tire is puncturing of the tire by a sharp object, such as a nail or pin, letting the air escape. Depending on the size of the puncture, the tire may deflate slowly or rapidly.
A tubeless tire is a pneumatic tire that does not require a separate inner tube.
A bead breaker is a tool used for separating tires from rims. The innermost diameter of the tire that interfaces with the rim of a wheel is called the tire bead. The bead is a thicker section of rubber, and is reinforced with braided steel cables, called the bead bundle. The surface of the bead creates a seal between the tire and rim on radial and bias-ply tires.
Inspection and maintenance of tires is about inspecting for wear and damage on tires so that adjustments or measures can be made to take better care of the tires so that they last longer, or to detect or predict if repairs or replacement of the tires becomes necessary. Tire maintenance for motor vehicles is based on several factors. The chief reason for tire replacement is friction from moving contact with road surfaces, causing the tread on the outer perimeter of tires to eventually wear away. When the tread depth becomes too shallow, like for example below 3.2 mm, the tire is worn out and should be replaced. The same rims can usually be used throughout the lifetime of the car. Other problems encountered in tire maintenance include:
A bicycle tire is a tire that fits on the wheel of a bicycle or similar vehicle. These tires may also be used on tricycles, wheelchairs, and handcycles, frequently for racing. Bicycle tires provide an important source of suspension, generate the lateral forces necessary for balancing and turning, and generate the longitudinal forces necessary for propulsion and braking. Although the use of a pneumatic tire greatly reduces rolling resistance compared to the use of a rigid wheel or solid tire, the tires are still typically the second largest source, after wind resistance, of power consumption on a level road. The modern detachable pneumatic bicycle tire contributed to the popularity and eventual dominance of the safety bicycle.
A tire changer is a machine used to help tire technicians dismount and mount tires with automobile wheels. After the wheel and tire assembly are removed from the automobile, the tire changer has all the components necessary to remove and replace the tire from the wheel. Different tire changers allow technicians to replace tires on automobiles, motorcycles and heavy-duty trucks. New tire and wheel technology has improved certain tire changers to be able to change a low profile tire or a run-flat tire.
The following outline is provided as an overview of and topical guide to tires: