What is the size of BMW 5 Series tire bolts?
3 Answers
BMW 5 Series tire bolts are 19mm in size. Introduction to tire bolts: Wheel hub bolts are high-strength bolts that connect the vehicle's wheels. The connection point is the wheel hub unit bearing! Generally, 10.9 grade bolts are used for mini vehicles, while 12.9 grade bolts are used for medium and large vehicles! The structure of wheel hub bolts usually consists of knurled splines and threaded sections, along with a cap head! T-head wheel hub bolts are mostly grade 8.8 or above, bearing the high torque connection between the car's wheel hub and axle! Double-ended wheel hub bolts are mostly grade 4.8 or above, bearing the lighter torque connection between the outer wheel hub shell and the tire. Function of tire bolts: Tire bolts refer to the bolts installed on the wheel hub that connect the wheel, brake disc, and wheel hub. Their function is to reliably connect the wheel, brake disc, and wheel hub together. As we know, the weight of the car is ultimately borne by the wheels, and the connection between the wheels and the car body is achieved through these bolts.
I often help friends change tires on BMW 5 Series. The wheel bolts on this car usually require a 19mm socket, while older models occasionally use 17mm. There are a few details to pay attention to when changing tires yourself: loosen the bolts in a diagonal sequence, don't remove them all at once; the factory-installed locking wheel bolts require a special key adapter, which is located under the trunk mat in the tool kit; finally, tighten to around 120 Nm for optimal security - too loose and the wheels may wobble at high speed, too tight and you risk stripping the threads for the next tire change. If you're unsure about the model year, the most reliable way is to check the size of the wrench in the vehicle's tool kit.
I've been driving a BMW 5 Series for three years, and a 19mm socket is generally sufficient for removing the wheel bolts. However, two things require attention: first, aftermarket alloy wheels might use special security bolts, so it's best to prepare the corresponding socket in advance; second, when purchasing a jack, choose one with a load capacity of over 2 tons, and make sure to position it correctly on the metal support points of the chassis, avoiding the side skirts. Once, during winter, I had a flat tire and found the bolts frozen. Since then, I've developed a habit of applying a thin layer of grease to the bolts every quarter to avoid delays during emergency tire changes.
