Any time you run 12mm spacers, longer wheel bolts are necessary hardware. Because the wheel and tire assembly must be held evenly and securely to the wheel hub by the wheel bolts. Now you have added 12mm space between the wheel and hub assembly, your OEM wheel bolts can’t provide enough thread for safely securing the wheels. If the lug bolts are not tightened securely, it can cause the wheel to vibrate, loosen and wobble. This can damage or even break the spacers and wheel bolts, potentially causing the wheel to separate from the vehicle.

When it comes to wheel bolts for 12mm spacers, the thread engagement length is critical. There is a golden rule: at the minimum, thread engagement length must be equal to or greater than the diameter of the fastener. In other words, if the bolt is 1/2-inch in diameter, the thread length must be at least 1/2-inch.

Do 12mm Spacers Need Longer Wheel Bolts BONOSS Forged Extended Wheel Bolts for BMW Cars (1)

How Long Wheel Bolts Do I Need for 12mm Spacers?

But it is not that longer wheel bolts are better. You may need to do some calculations. The length of thread engagement means the axial distance through which the fully formed threads of both the nut and bolt are in contact. It is one of the key factors. For instance, a standard thread forming bolt applied in 39mm of the material may have a 15mm thread length and a 14mm shank part. What really matters is the actual thread length that the wheel bolts can contact with the inner hub lug nuts.

If you don’t replace the rims, then the calculation will be quite simple. Standard bolts are 27mm long, so you can do the math for longer ones. Giving an example, if you install 12mm spacers on a 2022 BMW G30, then the wheel bolts you need will be: thread=M14x1.25, seat=conical/ball (depends on the wheels you are using), head 17mm, and length=39mm (standard 27mm + 12mm = 39mm). Too short, you can’t fasten the wheels and spacers correctly. Too long, you may meet vibration issues.

Do 12mm Spacers Need Longer Wheel Bolts BONOSS Forged Extended Wheel Bolts for BMW Cars (2)

Where’s Best to Buy Them From?

When shopping for new aftermarket wheel bolts, people always care about the quality. Because it turns out that there are actually a lot of advantages that running a set of high-performance wheel bolts produced by premium brand manufacturers. Genuine brand wheel bolts will provide vastly better performance across a broader range of road conditions than a cheap budget bolt from an unknown company.

BONOSS forged extended wheel bolts for 12mm spacers are made of high-strength SCM440 alloy steel. They have fully SGS, TÜV ISO Grade 12.9 certified, tensile strength≥1,282Mpa, limited life range test≥2,000,000 stress cycles without damage, ultimate tensile load≥152,000N, hardness (HV)≥395. These tire bolts are very high strength. In fact, they are the strongest wheel bolts that we have covered in the automotive world.