Measuring an axle intended for or used with disc brakes involves checking dimensions and characteristics critical for proper brake function and fitment. Based on the provided references, key measurements include axle offset and axle play (runout).
Understanding Key Measurements
When dealing with disc brakes on an axle, specific measurements are crucial for ensuring correct installation, rotor clearance, and caliper alignment. Two important aspects highlighted or implied by the references are:
- Axle Offset: This measurement is typically related to the distance from the axle flange to a reference point, ensuring the brake rotor sits correctly relative to the caliper mounting location. The reference explicitly mentions measuring axle offset in the context of rear disc brakes.
- Axle Play (Runout): This refers to the amount of side-to-side movement or wobble in the axle shaft or flange. Excessive play can cause rotor wobble, leading to vibration and uneven brake pad wear.
Measuring Axle Play (Runout)
The provided reference highlights the importance of measuring axle play, referring to it as a "difference." This measurement is critical for the performance and longevity of your disc brake system.
According to the reference:
"The difference is called axle. And play and if it exceeds 20,000th of an inch. Please call Wilwood for assistance."
- What is Measured: A "difference," which is termed "axle. And play." This refers to the amount of runout or lateral movement present in the axle.
- Tolerance: The acceptable limit for this "axle. And play" is stated as 20,000th of an inch (which is 0.020 inches or approximately 0.5 mm).
- Action Required: If this measured difference or play exceeds 20,000th of an inch, the reference advises contacting Wilwood for assistance, indicating that this level of play is outside acceptable limits for proper brake function.
Measuring axle play typically involves using a dial indicator mounted securely with its contact point touching the axle flange or rotor mounting surface. The axle is then slowly rotated, and the total variation shown on the dial indicator represents the runout or play.
Measuring Axle Offset
While the detailed procedure isn't provided in the text snippet, the title portion of the reference mentions "Measure Axle Offset for Rear Disc Brakes". This indicates that measuring axle offset is a necessary step when installing rear disc brakes. Axle offset measurements help determine the correct brake kit components needed and ensure the rotor and caliper align properly on the axle flange.
Accurate measurement of both axle offset and axle play is vital for the safe and effective operation of disc brakes.
