What is the most cost-efficient method to correct excessive lateral runout on a disc brake rotor?

• A. Balancing
• B. Indexing
• C. Grinding
• D. Replacing

Answer: (B)

Indexing is the most cost-efficient method to correct excessive lateral runout on a disc brake rotor because it involves repositioning the rotor on the hub to achieve better alignment and reduce runout.

When a rotor is installed, it may not sit perfectly flush against the hub, which can lead to uneven wear and performance issues. By indexing the rotor, technicians can shift its position slightly on the hub to find a point where the lateral runout is minimized, effectively improving the rotor's performance without the need for more intensive and costly repairs or replacements.

This method is preferable to balancing, as balancing typically addresses weight distribution rather than lateral alignment issues, making it less effective in this scenario. Grinding can resolve runout by removing material from the rotor, but it often requires specialized equipment and can be more expensive. Replacing the rotor is the least cost-efficient solution, as it involves the purchase of new components, when a simple adjustment might suffice. Thus, indexing stands out as the most practical and economical option available.