How to measure the stem size of your caster

If you have a caliper, measure the Grip Ring Stem in the section below the ring toward the caster body using your caliper. If it measures .437 + or – you have a 7/16″ diameter. If it measures .375 + or – you have a 3/8″ diameter. You do not need to use a second method to measure!

Many people have difficulty accurately measuring the grip ring stem ( mounting post ) on their chair or furniture casters. The “grip ring” is the “C” shaped metal clip which compresses when inserted in the holes in the bottom of the chair. It holds the caster in the hole. If you want to replace a caster that has a “grip ring stem”, first try measuring with a ruler. Place the ruler perpendicular to the length of the stem at the middle (not near the top or the ring). Most casters that have a grip ring stem have 7/16″ stem diameter. If the stem of your caster is 7/16″ diameter it will measure slightly less than the 1/2″ mark on the ruler. The only other grip ring stem diameter is 3/8″. On a ruler, 3/8″ appears half way between the 1/4″ and the 1/2″ marks.

If you measure 3/8″ diameter for your Grip Ring Stem, we’re sorry but we can not help you. We only sell chair and furniture casters with 7/16″ diameter Grip Ring Stems.

Second, you should double check your effort by trying one of the following:

Please use two of our methods to measure the stem diameter. Remember, measure twice – order once.

Method #1

Find the Diameter using some common tools.

Use some of the tools you have around the house to measure. If you have a set of open-end wrenches, use the wrench to check the diameter of the stem. There should be a little “wiggle” between the wrench and the stem. If you need to measure the diameter of the hole that the stem goes into, use a drill bit. Again, there should be a little wiggle but not much. Photos below will show you how it’s done. Always try “American” sizes first and “Metric”, only if you think it was not a good fit with the American size.