Page Contents
What is a Lug Stud?
A lug stud, also known as a wheel stud, is a threaded fastener that holds the wheel to the vehicle’s hub. Lug studs are screwed into holes on the hub forming a circle. The wheel has matching holes that align with the lug studs. Lug nuts are then threaded onto the protruding lug studs and tightened down to secure the wheel.
Lug studs are typically made from chrome-molybdenum or stainless steel for durability. The threads are rolled for added strength. On most vehicles, the lug studs are press fit into the hub but some use a ball seat lug stud that is free spinning.
When is it Necessary to Replace a Lug Stud?
There are a few situations when a lug stud may need to be replaced:
- The threads are damaged – This can happen from overtightening the lug nut or from cross-threading it. Damaged threads will prevent the lug nut from properly securing the wheel.
- The stud is bent or broken – Hitting a curb hard or overtightening can bend or shear off a lug stud. A damaged or broken lug stud needs to be replaced.
- Rust and corrosion – Exposure to water, salt, and dirt can cause lug studs to rust over time. This will weaken the stud and make removal difficult during tire changes. Rusty or corroded lug studs should be replaced.
- Worn or loose lug nuts – If the lug nuts become loose and require frequent re-tightening, the lug studs may be worn down. Worn studs will need to be replaced to keep the wheels securely fastened.
- Upgrading wheels and tires – When switching to larger diameter wheels or heavier duty tires, you may need lug studs with a higher strength grade.
Replacing even a single broken or damaged lug stud is important for safety. A full set of functional lug studs is necessary to properly center the wheel and keep it securely attached.
How to Remove the Broken Lug Stud
Removing a damaged, bent or broken lug stud takes some work, but can be accomplished with the right tools:
Things You’ll Need
- Lug wrench
- Hammer
- Punch or drift pin
- Penetrating oil
- Wheel blocks
- Jack and jack stands
- Lug stud extractor
- Socket set
- Torque wrench
Steps to Remove the Broken or Damaged Lug Stud:
- Loosen the lug nuts on the wheel where the damaged stud is located. Only loosen them, do not fully remove yet.
- Safely raise the vehicle and support it on jack stands.
- Remove the lug nuts and wheel from the hub where the damaged lug stud is.
- Apply penetrating oil liberally on the threads of the broken stud to help loosen it.
- Clamp a lug stud extractor onto the damaged stud if possible. Turn counter-clockwise to unthread it from the hub.
- If the stud spins or strips, use a hammer and punch/drift pin. Hammer the punch at the base of the stud to push it out while turning counter-clockwise.
- Once removed, clean any debris from the lug stud hole in the hub. Use brake cleaner and compressed air.
- Lower vehicle safely back to the ground after removing the broken stud.
Removing a seized, damaged or broken lug stud takes patience. Letting penetrating oil soak helps loosen the threads. Avoid using excessive force which could damage the hub. If you are unable to get the broken stud out, a professional mechanic can drill it out.
How to Install the New Lug Stud
Once you have removed the damaged lug stud, the new one can be installed:
Things You’ll Need
- Replacement lug stud of the correct type and size
- Wheel bearing grease
- Torque wrench
Steps for Installing a New Lug Stud:
- Inspect the replacement lug stud to ensure it matches the original and has undamaged threads.
- Apply a thin layer of wheel bearing grease on the stud’s threads.
- Thread the new lug stud clockwise into the open hole by hand until snug.
- Using a torque wrench, tighten the lug stud to the manufacturer’s specified torque. Typically between 75-100 ft-lbs.
- Install the wheel and hand tighten the lug nuts over the new stud.
- Once all lug nuts are threaded on by hand, torque them with the torque wrench to the proper spec in a star pattern.
- Road test the vehicle cautiously for a few miles and re-check the lug nut torque.
The wheel bearing grease on the stud’s threads will help it properly seat in the hub hole. Do not over tighten initially or the stud may become stretched or damaged. Retorque the lug nuts after 50-100 miles to ensure they stay tight.
Finding the Right Replacement Lug Stud
Finding the correct replacement lug stud is important for proper wheel fitment and safety. There are a few key factors involved:
- Thread pitch – Metric or SAE/UNC thread?
- Thread diameter – Lug nut size, common are M12x1.5, M12x1.25, 7/16″, 1/2″
- Length – Measure the protruding portion. Length impacts wheel fitment.
- Seat style – Conical or ball seat? Must match hub contact area.
- Material – Chrome alloy steel? Stainless steel?
- Strength – OEM standard? Upgraded?
The best way to get the exact replacement stud is to lookup the year, make and model. The vehicle owner’s manual will also have lug stud specs. Auto parts stores can match these details to provide the right stud. Buying high quality studs from reputable brands is recommended for durability.
Can You Drive with a Broken Lug Stud?
Driving any distance with a missing or broken lug stud is never recommended. A fully functional set is required to properly center and secure the wheel against the hub. However, in an emergency you may be able to drive a **very short distance** to get off the road or get home, provided:
– The wheel has at least 3 functional lug studs and nuts evenly spaced.
– Drive slowly under 35 mph, no high speeds or sudden turns.
– Go only a couple miles directly to repair facility.
– Brake gently and avoid potholes.
This is only in an emergency where the vehicle cannot be safely parked. The wheel is essentially only partially secured, so driving should be limited to an absolute minimum.
Longer distances or high speeds can allow the wheel to wobble and break other studs. This can quickly lead to a dangerous situation if the wheel fully detaches at speed.
Can I Drive with Missing Lug Nuts?
No, you should never drive with missing lug nuts even for short distances. Each lug nut is essential to properly mounting the wheel. Even a single missing lug nut will result in:
- The wheel not being fully seated against the hub.
- Extreme stress on remaining lug studs.
- Wheel wobble leading to detachment.
- Brake pulsation and damage.
- Difficult steering control.
A missing lug nut leads to an extremely hazardous situation and should be repaired immediately before attempting to drive. In some cases, a missing lug nut may shear off the stud itself when driving. Have the vehicle towed rather than attempting to drive it with any missing lug nuts.
Tips for Preventing Lug Stud Issues
Proper lug nut tightening and lug stud maintenance can help prevent problems and breakage:
- Always torque wheel lug nuts to the factory specification with a torque wrench.
- Follow the star or criss-cross tightening pattern to evenly seat the wheel.
- Retorque the lug nuts after 50-100 miles of driving with new wheels.
- Visually inspect lug studs frequently for signs of wear, corrosion or cracks.
- Never over-tighten lug nuts. This is the most common cause of damage.
- Avoid using impact wrenches for final tightening.
- Clean and lubricate lug studs when changing tires.
- Replace severely corroded, rusted or bent studs.
- Upgrade to chrome alloy or stainless steel lug studs if using oversized wheels.
Careful attention to proper lug stud torque specs and maintenance will keep them in good condition for the life of the vehicle. Periodically checking for wear or damage will allow broken studs to be replaced promptly.
Conclusion
Replacing a broken or damaged lug stud may seem daunting, but is doable with basic tools and mechanical ability. Always replace lug studs in pairs on the same hub to prevent uneven loading. Taking the time to find the exact OEM replacement stud ensures proper fit and safety. In an emergency, you may be able to limp the vehicle a very short distance to get off the road. But it’s critical to have fully functional and undamaged lug studs in order to safely operate any vehicle. Proper torqueing and periodic inspection will extend their lifespan.