 |
|
M + S
Mud and snow tires. Tires having a tread design for maximum traction in mud and snow.
|
|
Michelin X
Registered trademark for Michelin's steel belted radial cord tire.
|
(top)
|
 |
|
New treads (Nu-treads)
A term used by some tire companies to denote a retreaded tire.
|
|
Nibbling
The jerking action which occurs in a vehicle, due to the distortion within some tires as they are forced to traverse pavement ridges at a slight angle.
|
|
Non-directional tread
An arrangement of bars, grooves and ribs in a manner that gives equal traction in forward or reverse direction.
|
|
Nylon
A synthetic fiber.
|
(top)
|
 |
|
O Ring
An O-shaped rubber ring used in earthmover tubeless tire mountings to seal air between the loose taper seat and the rim base.
|
|
Odometer
(Mileage recording instrument.) A register showing miles driven by a vehicle, usually located in the speedometer.
|
|
OEM
Original equipment manufacturer. The term OEM tires refers to tires offered originally by the manufacturer of the vehicle at no extra cost, or the tire selected as an option and mounted by that manufacturer.
|
|
Offset
See rim and wheel terms.
|
|
Ounce inches
An expression of the force exerted by a heavy spot (or counterbalance weight) on a tire. Multiply the weight times its distance from the axle center, i.e.. 3 oz. x 7" = 21 ounce inches.
|
|
Out rigger
A device (retractable mechanical legs) used to stabilize equipment such as cranes, ditch diggers, etc., while working.
|
|
Outer cap nut
See dual mounting.
|
|
Over inflations
Excessive tire pressure in relation to the tire size and load carried.
|
|
Over cure
Vulcanizing longer than necessary. Can result in the deterioration of certain physical properties.
|
|
Overflow
Spew-out of tread compound at the mold parting line or at the edge of the matrix skirt which should be trimmed or buffed of f the finished product.
|
|
Overload
Carrying more weight on a tire than its listed maximum carrying capacity or, carrying excessive loads on a tire in relation to its inflation (underinflation).
|
|
Oversize
Installing a tire larger than needed to carry the load. A common practice on passenger vehicles to increase one size when replacing OEM (it is not necessarily beneficial).
|
|
Oversteer
A vehicle tends to turn on a smaller radius than that steered by the driver who finds he is tuming too acutely. An undesirable condition that can be caused by having larger "slip angle. in rear tires than in front tires. Also see tire deviation angle.
|
|
Ozone
A faintly blue form of oxygen produced by the silent discharge of electricity into the air.
|
|
Ozone checking
The cracking of rubber brought about by continued exposure to ozone in the air which, if extensive, is destructive to a tire.
|
|
Ozone compound
(Anti-ozone compound ) - Rubber compounded with certain chemicals to regard ozone damage.
|
(top)
|
 |
|
Parallelism, axle
Axles are determined to be parallel, thus minimizing tire wear, if a measurement between two or more axles is equal at both ends of the axle.
|
|
Patch
A simple repair unit such as used for a nail hole.
|
|
Payload
The actual weight of cargo being carried, including packaging, etc. (GWN - Unladen weight = payload).
|
|
Plug repair
The filling of a nail hole by forcing repair material into the damaged area to fill it, often while the tire is mounted and containing air. This not a satisfactory method of repair.
|
|
Ply
A layer of parallel cords coated in rubber forming the carcass body, stabilizing plies, etc.
|
|
Ply rating
The strength index of a tire. It replaced the old system of marking the actual number of carcass plies in a tire on its sidewall, and is an indication of comparable strength. This system is currently being replaced by the term load range.
|
|
Ply separation
A breakdown of bonding compounds causing plies to detach from each other. Usually as a result of excessive heat.
|
|
Ply turnup
The extension of a carcass ply to its end after wrapping around the bead.
|
|
Pneumatic tire
An air-filled tire. The air carries the load.
|
|
Polyester
A synthetic fiber.
|
|
Polymer
A material consisting of large units (molecules) made by joining many smaller building blocks (simple molecules). Usually used to describe synthetic rubber.
|
|
Power train
Components used in transmission of power from the engine to the wheels.
|
|
Pressure buildup
Heat causes air to expand resulting in a normal increase in air pressure. Any increase exceeding 15% above starting cold pressure should be investigated. See bleeding.
|
|
Probe
A pointed tool, like an icepick. It is used to determine the extent of injuries during the tire inspection. An awl.
|
|
Production retread shop
A shop which schedules its production not on the basis of day-to-day orders but rather on long runs of purchased casings in order to secure the lowest cost per unit.
|
|
PSI
Pounds per square inch. This is the accepted standard for measuring inflation pressure in a tire.
|
|
PTO
Power take-off, used to transmit power from engine to auxiliary equipment.
|
|
Puncture
Any penetrating of a tire's air chamber by a foreign object, nail, glass, etc. resulting in loss of air. Such loss can be rapid with the collapse of the innertube, or relatively slow in the case of tubeless tires.
|
|
Pyrometer
Instrument used to indicate temperature in various areas of the tire.
|
(top)
|
 |
|
Quality grading
Department of Transportation requirements for labeling of various tire safety and performance criteria by the manufacturer.
|
(top)
|
 |
|
Radial ply
Refers to the ply or plies used in tire in which the cords run at right angles to the bead and parallel to the tire radius.
|
|
Radial runout
A tire assembly that does not form a true circle; the radii of the circle are not equal. Most usual causes are bent wheels (out of round) or tires not mounted properly (beads not seated).
|
|
Radius
See loaded radius or free radius.
|
|
Radius rods
Metal arms attached to frame and axles for alignment
|
|
Rasp
A tool used to prepare a tire for section repair and for buffing prior to retreading.
|
|
Rayon
A synthetic fiber.
|
|
Regrooving
The act of cutting new tread grooves into the crown of the tire after the original tread is worn down. A practice forbidden by many states' laws.
|
|
Reinforcement
Any material, usually rubber and fabric, vulcanized to the tire to return strength to the cord body at an injury.
|
|
Repair gum
See cushion gum
|
|
Retread (recap)
A means of extending the life off a tire that has worn its original tread, yet still has a sound carcass. The casing is prepared by buffing of f tread rubber and vulcanizing new tread rubber stock in its place. A casing to which tread rubber has been affixed to extend the useable life of the tire after the original tread has been worn out.
Retreading terms
-
Buff contour
The specked shape of a buffed.
-
Buff line
The dividing line in the cross section of a tire between the buffed surface of the original tire and the new retread rubber.
-
Buffered radius
A dimension that ensures the proper contour of the buffed surface according to tire size and type and matrix dimensions.
-
Buffer
A machine used to rasp the old tread from the tire.
-
Buffing
Grinding or rasping off remaining tread rubber to give the casing proper texture to accept new retread stock and proper dimensions to fit the matrix.
-
Buffing template
A machined device of a specific shape used to obtain the required buffed contour.
-
Builder
A machine used to apply tread rubber to a casing.
-
Bold-up
The application of retread or repair rubber.
-
Camelback
Uncured retread rubber in crescent shape, available in various widths and depths according to size and type of tire being retreaded. See die size, below.
-
Cement
An adhesive compound of rubber and certain chemicals which effect cure, dissolved in rubber solvents.
-
Chamber
A pressure chamber used to vulcanize pre-cured tread stock to the buffed casing.
-
Cold cap
So called because the tire is placed in a pressure chamber in a temperature range of 195°-212° until bonding of pre-cured tread rubber is achieved. Also see hot cap.
-
Cure
Vulcanize uncured rubber through the application of heat, pressure and time to permanently shape and set the rubber to achieve the degree of hardness desired to protect it from the affects of normal operating temperatures and wear.
-
Curing rim
A special rim that supports the inflated tire during curing process.
-
Cure tube
A heavy tube within the tire that provides pressure to force the casing against the matrix during the curing process.
-
Curing gum
A soft, tacky rubber compound used in retreading and repair to facilitate bonding between different rubber compounds and between plies, etc. Also see rubber terms.
-
Die size
Retread rubber is designated by its crescent shaped dimensions in inches and eighths, and its thickness in 32nds of an inch. (Example: 66-72-16; the crown would measure 6 and 6 eighths, the base 7 and 2 eighths wide; and the thickness 16/32 of an inch, or gauge of the stock rubber.)
-
Elugger
A machine used to cut the lugs from tires prior to buffing.
-
Envelope
A thin rubber wrapper that surrounds the tread, sidewall and is tucked inside the curing rim during pre-cured cold process. retreading. It protects bonding materials from humidity within the chamber.
-
Filler strip
free flowing rubber used under the tread when added thickness is needed.
-
Full cap
New tread rubber is added to the buffed casing, covering the crown and shoulder areas.
-
Hot cap
-
The conventional method of retreading in which uncured rubber is added to a buffed casing and cured in the mold at temperatures of approximately 290°-300°. This temperature allows uncured rubber to flow in the matrix forming the tread design during vulcanization.
-
Matrix
That portion of the mold which surrounds the tire transferring heat to the uncured rubber and forming the tread pattern.
-
Mold
A device, that includes a matrix, enclosing the tire and supplying heat and pressure to effect curing.
-
Peaking
A condition, usually in the cushion rubber resulting from local material starvation and excessive flow from adjacent areas.
-
Procured tread rubber
Pre-cured rubber, usually of high density and available in various tread designs is lined with cushion gum before applying to a buffed casing using the cold cap method of retreading. Recently it has been applied in some hot cap molds employing a smooth matrix or other modifications.
-
Separation
The parting of retread rubber from the buffed casing.
-
Shelf-life
A time limitation for the storage of uncured retread materials (usually 6 months), beyond which certain properties are lost. Storage of materials in a cool, dark, dry environment insures quality.
-
Stripping stock
A rubber stock used to extend the wing of tread rubber.
-
Template (buffing template)
A pre-cut pattern, usually metal, used to determine the contour of a buffed tire.
-
Top cap
New tread rubber is added to the buffed casing, covering only the crown area.
|
|
Revolutions per minute (RPM)
The measured revolutions for a tire traveling one mile.
|
|
Reversion
Excessive heating of a cured rubber compound leading to deterioration of its physical properties.
|
|
Rib
The continuous raised portions of rubber that run circumferentially (straight or in a zigzag pattern) making up the tread on the tire. Also the term applies to various raised surfaces circling the sidewall, i.e., guiderib.
|
|
Rim pull
Actual amount of effort in pounds available at point of contact of tire and road surface.
|
|
Rim & wheel terms
-
Cast spoke assembly
part of the vehicle consisting of the brake chum and wheel spider, having 3, 5 or 6 spokes.
-
Demountable flange
A side ring or side and lock ring combination that retains the tire on the rim. It is removable to permit tire mounting or removal.
-
Disc wheel
The combination of a rim and a metal disc riveted or welded to its center.
-
Flange
The curved metal extremes of a rim that retain the tire on the rim base.
-
Gutter
The recessed on a truck rim base that holds the lock ring in place.
-
28° gutter bevel
Truck rims are beveled to provide for the gutter and this bevel matches a 28° taper on the inside of the cast spokes, holding the rim in place.
-
Lock ring
A metal ring which snaps into the rim gutter, holding the side ring in place.
-
Offset
An important measurement for positioning the tire to insure proper tracking of the vehicle and adequate dual spacing. See below:measurements, rim or measurements, wheel.
-
Rim (truck)
A metal assembly consisting of a base and either a side ring or a side and lock ring combination, which are removable from one side for tire mounting. The opposite side has a fixed flange to retain the tire. Note: Passenger and tubeless rims do not have removable side and lock rings.
-
Side ring
A demountable metal flange to hold the tire on the rim base. It can be self contained, locking into the gutter, or may be held in place by a lock ring, depending on the type.
Measurements, rim:
-
Flange height
Measured from top of flange to bead seat, and is the difference between overall diameter and nominal rim diameter, divided by two.
-
Nominal diameter
Measured bead seat to bead seat 180° opposite.
-
Nominal width
Measured between the flanges at the bead seat.
-
Overall diameter
Top of flange to top of flange 180° opposite.
-
Rim offset
A measurement in inches from the center of the rim (between the flanges) to the tip of the 28° gutter bevel.
MEASUREMENTS, WHEEL
-
Bolt hole
Diameter of the bolt hole.
-
Bolt hole circle
Diameter of a circle scribed through the bolt hole centers.
-
Center bore
The diameter of the opening in a disc which allows for protrusion of the axle hub.
-
Wheel offset
A measurement in inches from the center of the rim (between the flanges) to the outside face of the disc.
|
|
Rim bead taper by rim types:
-
Flat base
No taper at either bead seat (obsolete).
-
Intermediate
One tapered bead seat of 5° at the fixed flange.
-
Advanced
Both bead seats tapered 5°.
-
Semi-drop center
Both bead seats tapered 5°.
-
Drop center
|
|
Rim types
-
Drop center
A one piece rim having a deep center depression for passenger, light truck and tubeless truck mountings. The tire is mounted by moving a tire bead into the drop center, thus allowing the bead area 180° opposite to slide over the rim flange.
-
Flat base
In common usage, it applies to any truck rim not having a center depression. A demountable flange (consisting of 1 or 2 piece side/lock ring) permits the removal of the tire and holds it in place after installation.
-
Semi-drop center
A rim having a demountable flange, for use on light commercial application. A slight depression in the center of the rim facilitates the mounting and tire removal.
-
Semi-drop center
A term used to describe a two or three piece rim that employs a demountable flange.
|
|
RMA
Rubber Manufactures Association
|
|
Road hazard
Injury to a tire sustained in normal operation, excluding collision or vandalism and that is not reparable by accepted standards.
|
|
Roll-off, tire
Bead unseating due to running a tire while flat. Also, the sudden loss of air due to side forces, such as hard cornering, combined with underinflation. The safety ledge on passenger rims (a necessity for tubeless mountings) guards against a roll-off.
|
|
Rolling resistance
Sum of the forces at area of contact between a vehicle's tires and road surface acting against the direction of movement.
|
|
Rollsteer
A steering effect induced by load transfer from side to side. The axles may move out of their normal parallel relationship due to spring deflection.
|
|
RPM
Revolutions per mile or revolutions per minute.
|
|
Rubber terms
-
Bloom
A surface film on rubber, caused by the migration to the surface of sulphur, wax or other unreacted ingredients of the compound. It may be protective to the tire, and detrimental only if appearance is a major factor.
-
Brittlepoint
A low extreme temperature at which a rubber specimen fractures on sudden impact.
-
Gum stock (cushion gum)
Rubber compounds containing only the necessary ingredients for vulcanizing. Reinforcing fillers are not present in gum stock.
-
Natural rubber
Elastomer produced from latex, a milky sap, obtained from the rubber tree. An elastic and porous form of rubber.
-
Synthetic rubber
A man-made elastomer. The raw materials generally being derived from oily by-products. A non-elastic form of rubber.
-
Butyl
A non-porous form of synthetic rubber.
|
|
Run flat
Damage sustained by a tire due to driving with insufficient air pressure or while flat.
|
(top)
|
 |
|
SAE
Society of Automotive Engineers.
|
|
Safety ledge
A raised area (hump) around the circumference of the bead seat area of passenger wheels. Its function is to prevent the tire beads from becoming unseated during hard cornering or while running with low air pressure. A must with tubeless passenger tires.
|
|
Scrap-pile
Discarded tire casings having service life exhausted through wear or damage.
|
|
SDC
Semi-drop center rim. See rim types.
|
|
Secondary failure
The failure which occurs as a result of a primary failure.
|
|
Section height
The vertical measurement from bead seat to top of crown when mounted, inflated and not under load. (Overall diameter less nominal rim diameter, divided by two.)
|
|
Section repair
Reinforcement made to the casing when an injury has extended through the tread or sidewall of a tire. The damaged cord is removed and a new cord is replaced in the form of a repair unit or patch. (A major repair in the sidewall or tread of a tire. This repair unit must have cord material for reinforcement, made specifically for the type tire-bias-ply or radial.)
|
|
Section width
The measurement across the tire width at the widest point when mounted and inflated (not under load), excluding any decorative moldings.
|
|
Self-cleaning tread
A tread pattern with tapered grooves and ribs, bars, etc., arranged in a manner that resists packing loose materials, (mud, etc.) in the grooves.
|
|
Self vulcanation
Vulcanization at room temperature or above, activated by chemical agents without the application of heat from an outside source.
|
|
Separation
The parting or debonding of any adjacent parts of the tire (ply to ply, ply to rubber, etc.), usually due to excessive heat.
|
|
Separation solid tires
Rubber pulling away from steel band.
|
|
Serial numbers
The individual, consecutive numbering of tires during production. It may be a combination of letters and numbers molded on the sidewall.
Batch number
May be found in addition to a serial number to identify the tire with other tires manufactured during a given period.
|
|
Set-up
Premature vulcanization of a rubber compound during processing or storage.
|
|
Shelf life
See retread terms.
|
|
Shim
Thin metal plates used as spacers in vehicle alignment.
|
|
Shimmy
Side to side movement (or vibration) of a tire assembly.
|
|
Shock absorber
Vibration dampening device used with chassis springs to lessen road bounce.
|
|
Shoulder
Outer edges of tread.
|
|
Shredded wire
Short pieces of fine steel wire mixed into a tread or undertread compound.
|
|
Sidewall
That portion of a tire between the tread and bead.
|
|
Single bead
Refers to a tire built with only one wire bundle in the bead.
|
|
Sipe
A hairline groove cut into tread ribs, bars or blocks to improve traction on wet surfaces.
|
|
Skid
To slip, or lose traction, sliding out from the intended direction. Not to be confused with the terms drift or sup angle.
|
|
Skid depth
(Anti-skid depth) See tread depth.
|
|
Skins
Slang reference to vehicle tires
|
|
Skive
To skive; to cut into. Cut away rubber from an injury in preparation for a section repair.
|
|
Sleeve nuts
See dual mountings
|
|
Slewed axles
Axles out of parallel.
|
|
Slip angle
See tire deviation angle.
|
|
Soapstone
Lubricant used to prevent sticking between tire and tube.
|
|
Solids
Industrial tires made without an air chamber.
|
|
Spacer
-
For demountable rims
Used in cast spoke mountings, it is a band having the circumference of the spoke wheel and the rims. It fits between two rims in dual mounting to provide clearance between duals.
-
Between wheel spacer (obsolete)
It is a circular metal plate having a bolt hole circle and center bore and fitting between the faces of disc wheels to provide additional dual clearance.
|
|
Specific gravity
Weight of given volume of substance compared to that of an equal volume of water.
|
|
Speedometer
Instrument to indicate velocity in miles per hour.
|
|
Special mileage tire
(Regrooveable tire)
A tire manufactured with an extra layer of rubber between the cord body and the original tread design. This extra layer is designed for the purpose of recutting and regrooving, and is specifically labeled as a special mileage commercial tire.
|
|
Spread axle
Trailer axle, usually six to nine feet ahead of another axle and located near the center of the trailer.
|
|
Spreader, tire
Any device, manual or hydraulic, used to spread tire beads for inspection, repair, service, etc.
|
|
Spring
Flexible or elastic member supporting spring weight of vehicle with recovering properties of resuming to original shape when released after being distorted.
|
|
Spring brake
Emergency or auxiliary brake system utilizing a spring load as a force for braking. May be automatically actuated by low air pressure or mechanically controlled for use as a parking brake.
|
|
Spring clip
Small metal brackets insuring proper alignment of spring leaves.
|
|
Spring rate
Rate of deflection versus amount of load applied in other words, how much force is needed to bend a spring a given distance.
|
|
Spring seat
Support on which spring is anchored.
|
|
Stabilizer
Device used to stabilize vehicle during turns sometimes referred to as a sway bar.
|
|
Stabilizing plies
Two or more plies of steel, fiberglass, etc., forming a belt around the circumference of a tire, between carcass and tread rubber. It reduces tread distortion of radial and bias belted tires.
|
|
Standard rim
A rim that has been calibrated and found to meet the precise measurements specified by Tire and Rim Association, Inc. or, where applicable, by European Tire & Rim Association.
|
|
Static balance
See balance.
|
|
Steering arms
(Tie rod arms)
Arms attached to front axle steering system to effect turn of wheels.
|
|
Steering axis alignment
See alignment.
|
|
Steering axle
An axle that directs control of the vehicle. It can be powered or non-powered and more than one steering axle can be present.
|
|
Steering knuckle
A steel forging which includes the wheel spindle. In cars it is the spindle support arm which pivots on ball joints. In trucks with non-independent front suspension, it pivots on the kingpin.
|
|
Stitching
A hard rolling method used to both remove trapped air and improve rubber contact for better adhesion during repair and retreading.
|
|
Suspension
Attaching parts including springs for securing axle or axles to chassis frame.
|
(top)
|
|
