Measure the inside diameter to the nearest 1/16th of an inch. In most cases, the cones inserted in each end of the spring will have a manufacturers name (OHD or Raynor, etc.) which will give a clue toward the proper identity. The chart on the right shows common IDs used by various manufacturers. If no manufacturers name is evident, usually a part number on the cone will indicate the inside diameter: 134 or 175 = 1 3/4" ID 258 or 263 = 2 5/8" ID 375 or 334 = 3 3/4" ID
