Hardware - nuts & Bolts
Using the wrong seat type can cause wheels to loosen, vibrate, or even detach while driving.
The "seat" is the part of the bolt or nut that contacts your wheel. Each wheel is designed for a specific seat shape. Mixing seat types won't properly centre or secure your wheel.
Tapered (Conical)
60° angled seat. Common on BMW and many aftermarket wheels.
BMW / AftermarketRadius (Ball)
Rounded seat, typically R12-R14 radius. Used by VW, Audi, Mercedes, Skoda, and VAG group.
VW / VAG / MercedesFlat (Mag / Washer)
Flat contact surface with washer. Common on Toyota, Lexus, Land Rover, and mag-style aftermarket wheels.
Toyota / Land RoverTuner (Spline Drive)
Narrow body with tapered seat. Fits small wheel holes, requires special key. Popular for aftermarket wheels.
AftermarketWheel bolts for the BMW Z4 I (E85) (2002–2005)
The BMW Z4 I (E85) (2002–2005) uses M12 x 1.5 wheel bolts with a tapered (60° conical) seat on its original wheels. PCD 5x120 — 5 bolts per wheel, 20 for a set of four.
| Fixing | Bolts |
|---|---|
| Thread | M12 x 1.5 |
| OE seat type | Tapered (60° conical) seat |
| PCD | 5x120 |
| Bolts per wheel | 5 |
| Torque | 115 Nm |
| OE bolt length | 26mm |
Seat type must match the wheels the bolts secure, not just the vehicle: this vehicle's original wheels take a tapered (60° conical) seat, but most aftermarket alloys use a 60° conical seat. If the car is on aftermarket wheels, check the wheel's seat before ordering — bolts with the wrong seat are unsafe at any torque.
Also for this vehicle: Alloy wheels · Locking kits · Spigot rings
