Li, La and Lp belt size difference

Li, La, and Lp are different ways of describing belt length. Buyers, dealers, and workshops in Pakistan should not assume the markings are interchangeable because the same belt can be listed under different measurement systems.

What the markings mean

Li usually refers to the inside length, La to the outside length, and Lp to the pitch length of a belt. The pitch length is the most useful reference for matching the working length used in the drive system.

Why the sizes differ

Belt materials and construction place the measurement at different points in the belt cross-section. That is why the same physical belt may show different numbers depending on whether the marking is Li, La, or Lp.

Use cases for Pakistani buyers

• Workshops often replace belts by reading the marking on the old belt.
• Dealers need the exact marking to avoid size mismatch when serving repeat customers.
• Buyers sourcing from China imported belts Pakistan suppliers should confirm the reference system first.
• V belts Pakistan and timing belts Pakistan orders can fail if the wrong length convention is assumed.

What customers should confirm before ordering

• The exact marking printed on the belt.
• Whether the measurement is Li, La, or Lp.
• The machine or vehicle application.
• The quantity and delivery city.

Practical note

The safest approach is to match the old belt marking exactly and share a clear photo when possible. That reduces the risk of sending the wrong belt size.