Wheel spacers are sandwiched between the assembly hub and wheel. The wheel lugs apply a clamping force to secure the spacer and wheel to the vehicle hub. When the lug nuts/bolts are properly tightened, the wheel lugs will stretch elastically (like very stiff springs) to keep everything in the right place. They have existed for multiple decades, and there is very little opportunity for wheel spacers failure. They have always been used widely, even within the highest level of racing events. The common myth is that wheel adapters wreck the physics of the wheels and wheel assembly. This is actually incorrect because installing a wheel adapter will not change these physics. We’ve seen them work successfully on race cars countless times, as long as you use high-quality adapters and install them properly, wheel adapters are just as safe as normal wheel changing.