SidewallThe part of the tire between the tread and the bead. It is mostly rubber reinforced with fabric or steel cords, and it holds the air in. The air, not the rubber, carries nearly all of the car's weight.
Rim flangeThe upturned edge on each side of the rim. It supports the tire at the side, and a tire has to be lifted over it to be fitted. Rim width is the distance between the two flanges.
Balance weight (wheel weight)Small weights added to the wheel to cancel any heavy spot. They go on after a tire is mounted and the assembly is checked on a balancing machine. An unbalanced wheel can shake the car and the steering wheel.
Valve stemA self-closing valve that lets air into the tire. It is then held shut by the pressure inside, by a spring, or by both. Almost every car tire uses the Schrader type.
SpokesThey run from the center of the wheel out to the rim. Like the wheel disc, they belong to the wheel and not to the rim. The thin wire kind are held in tension, which makes a wheel both stiff and light.
Brake disc (rotor)The turning part of a disc brake. A caliper squeezes a pair of pads against it and the car's motion becomes heat. It is usually cast iron, and many front ones are ventilated to shed that heat.
Bolt holeA wheel has one for each stud. The bolt pattern gives their number and the diameter of the circle they sit on: 5x100 means five on a 100 mm circle. The pocket around each one is the lug seat, shaped to match the nut.
Lug nut (wheel nut)A nut that holds the wheel on a stud. The end that meets the wheel is tapered, normally at 60 degrees, or rounded, which helps center the wheel. Nuts are tightened in a star pattern so the wheel clamps evenly.
Center capA decorative disk over the middle of the wheel. Early ones kept dirt off the spindle nut and the wheel bearings. Some are held by spring clips and others by the lug nuts.
Cut-away: inside the wheel 14
TreadThe tire's part that touches the road. The patch touching the road at any instant is the contact patch. The grooves between its ribs belong to the tread pattern.
BeadThe tire's edge, seated on the rim. It is made of high-tensile steel wire coated in rubber, and air pressure holds it in place so the tire seals against the wheel.
Bead seatThe surface of the rim that the tire bead sits on. On a tubeless wheel it is the surface that seals the air in, and a wheel's diameter is measured here, not at the outer edge.
RimThe wheel's outer edge, which holds the tire. Strictly it is only this hoop: the spokes and the center are the rest of the wheel, though the two words are often used as if they meant the same.
Drop center (well)The channel around the middle of the rim. To fit a tire, one side of the bead is pushed down into it, which gives enough slack to lift the other side over the flange. Car rims are of this type.
Wheel disc (wheel center)The center section that connects the rim to the car. Also called the spider. It is part of the wheel but not part of the rim. Steel wheels are usually sheet metal, pressed and welded together, and most alloy wheels are cast.
Hub mounting surfaceThe flat face that is clamped against the hub. Offset is the distance from this face to the wheel's centerline. A positive offset puts the face nearer the street side, as on most front-wheel-drive cars.
Center boreThe middle hole that centers the wheel on the hub. A wheel whose hole matches the hub exactly is called hub-centric. If the hole is larger, the lug nuts do the centering, or a ring is fitted to fill the gap.
Wheel studA threaded pin in the hub. It stays there when the wheel comes off. The press-in kind has a splined section called the knurl, slightly larger than its hole, so it cannot turn. Some cars have none and use wheel bolts instead.
Wheel hubThe part the wheel bolts to. It sits between the brake disc and the drive axle, and on a driven wheel its splined center mates with the axle shaft. Sold with its bearing built in, it is a hub assembly.
Wheel bearingLets the hub and the wheel turn freely. On many cars it is sealed inside the hub assembly, which is why that assembly is also called a wheel hub bearing.
Outer CV jointJoins the axle shaft to the hub. A constant-velocity joint keeps both sides turning at the same speed while the shaft runs at an angle, so a driven front wheel can steer and ride over bumps.
CV bootKeeps grease in the joint and dirt out. A flexible rubber cover, also called a CV gaiter. A split one lets the grease escape, which is a common reason a CV axle fails.
Axle shaft (CV axle)The shaft that carries power to the wheel. Also called a half shaft. A front-wheel-drive car has two, one from the transmission to each front wheel, each with an inner and an outer CV joint.
How this list was compiled: Part names and facts were checked on 2026-09-19, and a part is ringed only if Wikipedia and at least one maker, trade or government reference both name it. (1) Wikipedia: https://en.wikipedia.org/wiki/Wheel , https://en.wikipedia.org/wiki/Rim_(wheel) , https://en.wikipedia.org/wiki/Wheel_construction , https://en.wikipedia.org/wiki/Wheel_sizing , https://en.wikipedia.org/wiki/Alloy_wheel , https://en.wikipedia.org/wiki/Lug_nut , https://en.wikipedia.org/wiki/Wheel_stud , https://en.wikipedia.org/wiki/Center_cap , https://en.wikipedia.org/wiki/Hubcap , https://en.wikipedia.org/wiki/Valve_stem , https://en.wikipedia.org/wiki/Tire , https://en.wikipedia.org/wiki/Tire_bead , https://en.wikipedia.org/wiki/Tire_balance , https://en.wikipedia.org/wiki/Tire_changer , https://en.wikipedia.org/wiki/Wheel_hub_assembly , https://en.wikipedia.org/wiki/Disc_brake , https://en.wikipedia.org/wiki/Axle , https://en.wikipedia.org/wiki/Constant-velocity_joint . (2) Les Schwab Tire Centers learning center: https://www.lesschwab.com/article/wheels/rims-wheels-hubcaps-differences.html , https://www.lesschwab.com/article/wheels/lug-nuts-torque.html , https://www.lesschwab.com/article/wheels/what-is-wheel-offset.html , https://www.lesschwab.com/article/tires/tire-balancing-and-wheel-alignment.html . (3) Wheel-Size.com fitment guides: https://www.wheel-size.com/articles/centre-bore/ , https://www.wheel-size.com/articles/wheel-fasteners-guide/ , https://www.wheel-size.com/articles/wheel-offset-and-backspacing/ , https://www.wheel-size.com/articles/steel-alloy-forged-wheel-types/ . (4) Accuride Wheels Safety and Service Manual W3.000 Rev. 4: https://www.accuridecorp.com/sites/default/files/resources/2024-10/W3.000%20Rev.%204%20Accuride%20Wheels%20Safety%20Service%20Manual.pdf . (5) MOOG Parts: https://www.moogparts.com/parts/wheel-end/hub-assemblies.html and https://www.moogparts.com/parts-matter/What-is-a-CV-Axle.html . (6) US Code of Federal Regulations, 49 CFR 571.139 and 49 CFR 570.10: https://www.ecfr.gov/current/title-49/subtitle-B/chapter-V/part-571/subpart-B/section-571.139 and https://www.ecfr.gov/current/title-49/subtitle-B/chapter-V/part-570/subpart-A/section-570.10 . (7) Wagner Brake: https://www.wagnerbrake.com/technical/parts-matter/automotive-repair-and-maintenance/what-is-a-complete-brake-job.html . The wording of every label, hint and fact is our own. Licence: own work
The drawing: Drawn for this site, 2026-09-20. Original line drawing: nothing was traced and no maker's wheel was copied. Proportions and the way the parts fit were checked against the text of https://en.wikipedia.org/wiki/Rim_(wheel) , https://en.wikipedia.org/wiki/Wheel_sizing , https://en.wikipedia.org/wiki/Wheel_hub_assembly , https://en.wikipedia.org/wiki/Constant-velocity_joint and https://www.wheel-size.com/articles/steel-alloy-forged-wheel-types/ , read on 2026-09-20. Licence: own work
How it works
One front wheel of a front-wheel-drive car, drawn twice: from the street side, and cut through the axle line. The two figures carry 23 parts of a car wheel, from the tread to the axle shaft. Tap or click each part, name the ring that lights up, or press Print blank or Print labelled for paper.
Read the full guide
Two figures, 23 parts, three groups
The front view has 9 rings for the parts of a wheel on a car that show from the curb, such as the sidewall, the valve stem and the spokes. One lug nut is left off so the bolt hole shows. The cut-away holds the other 14. Three more groups run across both figures: tire and rim (9 parts), wheel center and lug nuts (7), and hub, brake and axle (7). Study writes every name on the drawing.
Rim, wheel and hub are three things
Strictly, the rim is the hoop that holds the tire. The parts of a rim are its two flanges, the bead seats inside them and the drop center between. Spokes and the wheel disc join that hoop to the hub mounting surface, which the lug nuts clamp to the hub. Read from right to left, the cut-away gives the parts of a car wheel and axle in the order power reaches them.
The bead belongs to the tire, and the bead seat is the metal shelf of the rim it rests on.
More options has Name it, with four choices, and Type it. After a round, press Practise the 3 you missed.
Lug nut and wheel stud are separate answers. The stud is the threaded pin that stays in the hub.
Questions and answers
Is the rim the same thing as the wheel?
Not strictly. The wheel is the rim plus the center that bolts to the car. Here Rim is ring 13, and wheel rim or barrel also counts when you type.
Which car is this wheel from?
No particular one. It is a plain five-spoke alloy wheel on a driven front hub, so one drawing can reach from the tire to the axle shaft. Some cars use wheel bolts in place of studs and nuts, and a wheel that is not driven has no CV joint behind it.
What is left out, and why?
Safety hump and steering knuckle are drawn but not ringed, because each turned up in one place only. A part is ringed only when an encyclopedia article and at least one maker, retailer, fitment guide or federal standard use the same name, as checked on September 19, 2026.