The materials of automobile wheel bolts usually include the following:

1. Steel: Steel is the most common material for wheel bolts, with good strength and corrosion resistance. Usually made of carbon steel or alloy steel, it can bear the high-strength load during the running of the vehicle and ensure the firm connection between the wheel and the hub of the vehicle.

2. Stainless steel: Stainless steel wheel bolts have excellent corrosion resistance and are suitable for vehicles running in wet or rainy environment. Stainless steel wheel bolts can effectively prevent corrosion and prolong service life.

3. Aluminum alloy: Aluminum alloy wheel bolts are lighter than steel, which can reduce the weight of wheels and vehicle hubs and improve the fuel economy and performance of vehicles. Aluminum alloy wheel bolts are usually made of high strength aluminum alloy, which has good strength and corrosion resistance.

4. Titanium alloy: Titanium alloy wheel bolts have extremely high strength and lightweight characteristics, which can improve the performance and handling of vehicles. Titanium alloy wheel bolts are usually used in high-performance racing cars or supercars, which require higher strength and lighter weight.

When selecting the material of wheel bolts, it is necessary to comprehensively consider the use environment, driving conditions and performance requirements of the vehicle. Different materials of wheel bolts have different characteristics and application scope. Choosing the appropriate material of wheel bolts can ensure the safety and stability of vehicle driving.