Lug nuts or bolts
Another thing to consider when new wheels are purchased is proper lug nuts or bolts. They are usually either flat, tapered (generally at 60 degrees and referred to as conical seat), or ball seats, meaning the mounting surfaces are flat, tapered, or spherical respectively. For example, most Mercedes have ball lug seats from the factory while most aftermarket wheels have a tapered lug design. If you buy aftermarket wheels for a Mercedes make sure you get the proper lug nuts for the wheel or the wheel will not be properly centered. Some manufacturers (e.g. Toyota and Lexus) have used taper lug nuts for steel wheels and flat seated lug nuts for alloy wheels.
Some aftermarket wheels will only fit smaller lug nuts, or not allow an ordinary lug nut to be properly torqued down because a socket will not fit into the lug hole. Tuner lug nuts were created to solve the problem. Tuner lug nuts utilize a special key to allow removal and installation with standard lug wrench or socket. The design of tuner lug nuts can range from bit style to multisided or spline drive , and are sometimes lightweight for performance purposes. A variation is the "locking wheel nut", which is almost universally used for alloy wheels in the United Kingdom. One standard lug nut on each wheel is replaced with a nut which requires a special and unique key (typically a computer-designed, rounded star shape) to fit and remove the nut. This helps to discourage theft of wheels. However, universal removal tools are available which grip the head of the locking nut using a hardened left-hand thread. The success of these depends on whether there is room to use it in the lug hole, and whether the manufacturer has incorporated a free-spinning outer casing to the lock.
- Make sure to keep a set of lugs that fit your spare tire.
- Keep a key to aftermarket lug nuts and locking nuts in the car in case of a flat.
- Keep the key in the trunk if possible to help reduce the risk of theft.(If your key is in the front part of the car thieves need only break into the car to have access to your lug key.)