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 Fiat 500, 312 (2007–2024)
The Fiat 500, 312 (2007–2024) uses M12x1.25 wheel bolts with a tapered (60° conical) seat on its original wheels. PCD 4x98 — 4 bolts per wheel, 16 for a set of four.
| Fixing | Bolts |
|---|---|
| Thread | M12x1.25 |
| OE seat type | Tapered (60° conical) seat |
| PCD | 4x98 |
| Bolts per wheel | 4 |
| 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
