Wheel Nuts & Bolts

Wheel nuts are chosen by four measurements: thread, seat, hex and length. Each has to match both the car and the wheel, and a nut that is wrong on any of them does not hold the wheel properly.

Thread size and pitch

Most Japanese cars use M12 nuts, in either a 1.5 mm or a 1.25 mm thread pitch, and some use M14 x P1.5. The pitch follows the platform rather than the badge: the Toyota 86 takes M12 x P1.25, the size Subaru uses, and so do Suzuki-built cars sold under other makers' names. Check the car's own specification. Nut sets are made in each size; RAYS's duralumin L42 set, for example, comes in M12 x P1.5, M12 x P1.25 and M14 x P1.5.

Seat type

The nut's seat must match the wheel's. Most aftermarket wheels use a 60° taper seat. Honda's factory wheels use a ball (radius) seat, and some factory alloys use a flat seat with a washer. A ball-seat nut on a taper-seat wheel, or the reverse, touches on a thin ring instead of a full face and will not hold the wheel securely. Factory nuts are usually the wrong seat for aftermarket wheels, so budget for new nuts with new wheels.

Hex, length, open or closed

The most common hex sizes are 17, 19 and 21 mm. A slim 17 mm hex nut fits wheels with narrow nut holes, and RAYS's 17HEX sets come with a key adapter to turn them. Closed (bag) nuts keep water and dirt off the stud but cannot seat if the stud is longer than the nut; open-ended nuts suit long studs. A longer nut gives more thread engagement, so check how far the stud stands out from the wheel face before choosing a length.

Steel nuts are the everyday choice. Duralumin nuts, which RAYS makes from A7075 aluminium alloy, save weight. A lock nut set replaces one nut per wheel with a keyed lock.

When the studs are too short

Wheel spacers or a thick wheel centre can leave too little stud for a safe engagement. Longer hub bolts are the fix, and a bolt-on spacer comes with its own studs. Finish the job with centre caps; more on fitment is in the wheels guide.