Important! Measure Your Car Hub Before Installing Wheel Spacers
Don't install your spacers until you’ve checked these three safety essentials: The Depth Rule: Your spacer must be 2–3mm thicker than your car’s hub snout length. If your hub is 15mm, a 15mm spacer will hit the internal "shelf" and crack. (Exception: "Straight-through" adapters like 57.1mm to 66.6mm). The Mercedes Taper: Many Mercedes hubs change diameter or have a "step." If your spacer doesn't have a matching beveled (chamfered) edge, it won't sit flush. The 7mm Lip Rule: If using thin spacers (under 10mm), your car’s hub must still poke through the spacer by at least 7mm to support the wheel. The Paper Test: After sliding the spacer on, try to slide a piece of paper between the spacer and the car. If it fits, stop! The spacer is bottoming out and is unsafe to drive. Pro Tip: Hub lengths often differ between the front and rear of the same car—measure both!