What are your wheel studs and how do they function?
Vehicle wheel studs are high-strength, threaded steel fasteners that securely keep the wheel and tire assembly to the axle hub. Usually, there are 4 to 6 studs per wheel that are pressed or threaded into the wheel hub. The wheel and tire assembly is installed on the hub centering ring and the studs that protrude from the hub through the wheel mounting holes. Lug nuts are usually threaded onto the studs to securely keep the wheel to the hub.
When to consider changing wheel studs:
- Your wheel is loose or wobbling.The wheel and tire assembly has to be held evenly and securely to the wheel hub by the lug nuts linked to the studs. If the lug nuts are not tightened securely, it can make the wheel to vibrate, loosen and wobble, that can damage or even break the wheel studs and lug nuts, potentially making the wheel to separate from the car.
- A missing or broken studs, or damaged threads.If the stud gets missing or broken, the lug nut linked to the stud will be missing and the wheel will hold securely. When the threads on the stud are worn, rusted away, or else damaged, the lug nut may not achieve the needed torque and could come loose while driving.
- Stud turns in position when fastening lug nut.When the stud spins in the wheel hub while tightening, it should be changed. During replacement, the mounting hole in the wheel hub should be checked for damage.
How do mechanics change wheel studs?
- The vehicle is raised and supported on steel jack stands.
- The wheel and tire assembly, brake rotor, and caliper are taken off.
- On cars where there is sufficient access at the back of the wheel hub, a compact tool is used to press the defective stud out of the hub.
- On cars where there is no access to use a compact stud remover, the wheel hub must be taken out. When the hub must be pressed out of the steering knuckle, the wheel bearing is typically changed in the process of removing the hub. Oftentimes, the entire hub and bearing assembly with the studs included can be changed.
- The new stud or studs are pressed into position from the back of the hub, the brake caliper and rotor are reinstalled, and the wheel is put onto the studs.
- The wheel lug nuts are tightened to the factory specifications.
Is it safe to drive with wheel stud issues?
No, but you can momentarily drive a car at low speeds and for short trips with one missing wheel stud. However, if more than two studs are broken, it is advised to repair the vehicle prior to further use. Having all wheel studs in position with evenly tightened lug nuts keeps distortion of the brake rotor. Over longer periods, missing studs can damage the brake rotor, the wheel, and the remaining studs. A vehicle may vibrate when driving with missing wheel studs and can make the other studs or lug nuts to be loosened. This can result to the wheel separating from your tire during driving.
When changing wheel studs bear this in mind:
- Wheel studs are produced of high-strength steel. If a stud has broken, it is often because of previous overtightening. Lug nuts must be tightened using a calibrated torque wrench or a torque limiting tool.
- Published torque values think that studs are dry, clean, and free of all lubricants. Oil, grease, anti-seize or any similar compound should not be applied to the threads of a wheel stud or lug nut.
- Should a car require removal of the wheel hub to add a new wheel stud, studs on the hub should be changed? However, only defective studs have to be replaced if there is access from the back of the hub.
- Lug nuts should get tightened in a star or crisscross pattern specified by the original equipment manufacturer so as to avoid warping of the brake rotor or drum as well as damaging the wheel.