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Center Lock Installation Instructions

Installation Instructions for Forgeline Pin-Drive Center-Lock Wheels


  • Read before mounting tire on wheels. Wheels cannot be returned for fitment reasons after tires have been mounted.
  • Stud length protruding past the provided lug nut/drive pin may not allow wheels to be tightened properly. If the factory wheel stud protrudes past the end of the lug nut, you must check clearance of the wheel. Studs may need to be cut down for wheel to sit properly.
  • Read and observe all warning and instruction labels affixed to wheels. Installer must not exceed load rating specifications.
  1. Fail to check clearance of studs if they are longer than provided lug nut.
  2. Install adapters on wrong side of car.
  3. Use parts that are worn out.
  4. Fail to retighten caps.
  5. Tow vehicle backwards.
  6. Fail to use safety lock pins or Flush Loc caps.



Clean Hubs

 Clean and inspect hubs and brake drums for any obstructions, (lock clips, rivets, balancing weights, etc.). Remove or resolve any obstruction that prevents a flush fit between the adapter and the axle hub.

 Install Adapters

 Note: Right side (passenger side) adapters have reverse threads and a single line machined on the outside edge of plate. Left side (driver’s side) adapters have right hand threads and no line.

Check stud length. If the stud is longer than provided lug nut/drive pin you may need to cut the stud to shorten or use a spacer behind the adapter.

To install, correctly place left adapter on left side of car (Driver’s Side – U.S. Spec. Vehicles). Right adapter must be installed on right side of car. Adapters must be installed with the supplied pin-drive lug nuts. NO SUBSTITUTIONS! THIS IS IMPORTANT! DO NOT INSTALL ANY OTHER WAY!

After adapters have been placed on hubs, be sure that adapter plate fits flat against hub and hub mounting pad. If there is any interference point of contact must be found and any high point removed. If this is not done, wheels will not run true when installed.

When tightening pin-drive lug nuts:

– Minimum thread engagement must be at least one times the diameter of the stud i.e., the typical thread      engagement for a ½” x 20  thread would be a minimum of 1/2,” of thread.

– If spacers are used, be certain that the spacer is in place during this inspection.

– Do not lubricate the pin-drive lug nuts or stud threads. Run all pin-drive lugs up fully before tightening.

– Tighten all pin-drive lug nuts using a criss-cross pattern to assure an even distribution of pressure while tightening.

– Once installed, adapters should rotate freely by hand with no rubbing or interference.


Be certain that you use the proper Forgeline pin-drive lugs for your specific Forgeline Centerlock Wheel. Use of any other lug nut can create an unsafe condition and void your warranty.

Fit Wheels


Apply a thin coating of anti-seize to the outside threads of the adapter and the threads inside the nut.

– Also, place a thin coating of anti-seize on taper or bevel on back of the centerlock nut and the taper of the wheel (where the nut tightens down on the wheel). Keep dirt away from threads.

-Using grease instead of anti-seize is not recommended.

 Place wheels on adapters, aligning the pins with the corresponding holes on the back of the wheel center. Push the wheel firmly toward the back of the adapter. When the rear of the wheel center is sitting on the back of the adapter, rock the wheel so that the drive pins engage completely and firmly. Wheel should sit completely flat on adapter. If wheel does not sit flat, check to make sure stud length is not too long.

Thread On Nut

Thread nut on the adapter. Note proper tightening direction. Right side nuts and adapters have reverse threads and a single line machined on the outside of them. Left side nuts have right hand threads and no line on side of cap.  “Left side” nuts must be used on the left side (Driver’s Side) of car and “Right side” caps must be used on right side of car.

 Tighten Nut

Nuts on right side of the car will tighten counter-clockwise, nuts on left side will tighten clockwise. Newer style nuts will have directional arrows engraved on them. While car is still on jacks run the centerlock nuts up tight. You may need someone to apply the brake while you tighten the wheel.


Spin wheels by hand to make sure there is no rubbing against brake calipers and wheel spins straight. Also, rock wheel assembly to verify that the nut has seated completely in the wheel. Assembly should be very solid, with no rocking movement noticeable.

 Retighten Caps

Lower the car and tighten the nuts until there is no movement with 150  pounds (entire body weight) at the end of the 25” breaker bar. If torque wrench is available, torque to 300 ft-lbs. Do not over tighten!!!

 Install Flush-Loc Caps or Safety Pin

On original style Center-Lock, install safety pin with clip. If Flush-Loc application, install Flush-Loc Caps on the appropriate sides of the car by threading them into the center of the nut. They should thread in the same direction as the nut on each side of the car. Thread in with supplied wrench until spring washer is completely crushed. This will be about 15 ft lbs. The Flush-Loc cap wrench is supplied with a 3/8” square for a socket wrench if needed.

Run-in and retighten

After the car has been run 25 miles, be sure to re-check the nut for tightness. The wheels seat themselves on the adapters after the initial run-in and nuts can be tightened further. THIS IS VERY IMPORTANT. Check for tightness, but do not over tighten.


© Forgeline Motorsports, LLC