How to Measure Your Existing Caster Stem

If you need to replace a chair caster or any light duty caster with a stem, we need to know the measurements of your existing stem. This is probably the most important step in replacing a caster, and we will need to know this information before we can place your order.

Determine Your Stem Style

Grip Ring Stem
Grip Neck Stem
Threaded Stem


To view "How to Replace Stem Caster" video in full-size click expand icon or click the YouTube button at the bottom of the video window.

Let Us Help You!
If for any reason you do not want to go through the process of measuring and getting the specs of your existing caster... that is okay, we can measure it for you.

Just send us one of your existing casters with contact information to:
Service Caster Corporation
Attn: Home & Office Casters
Riverfront Business Center
9 South First Avenue
West Reading, PA 19611

See what Service Caster customers are saying:


Measuring a Grip Ring Stem

Grip ring stems are one of the most common connection types for office chairs. For the most accurate results a micrometer or caliper should be used to measure the diameter of the stem, but below we will demonstrate some ways to get the measurements using common household items. We recommend using at least 2 of the methods described below to ensure accuracy.

Measuring With a Wrench

Measuring with a Wrench

To measure a Grip Ring stem with a wrench, simply gather both a 7/16" and 3/8" wrench. Place the open end of the wrench around the stem, as shown to the right.

Whichever wrench fits almost perfectly will be the size of your stem.

Note: A tiny bit of wiggle room or "play" is to be expected when using the wrench method. The 3/8" wrench will never fit on a 7/16" stem, and a 7/16" wrench will be very loose on a 3/8" stem.


Printout Measuring

Measuring with a Printout

This printout page can help you determine the size of your grip ring. Simply open the link, and print the page. Then, place your stem over the images that most closely resemble your stem. Whichever one is a perfect match is your stem.

Printout Measuring

Click Here for Printout


Paper Wrap Measuring

Paper Wrap Method

For this method of measurement, simply take a small strip of paper and wrap it around the stem. Mark the paper with a pen or pencil where it overlaps, careful to keep the wrap tight. Then measure the strip from the start of the wrap to the mark.

If the ruler measures 1-3/16", you have a 3/8" diameter stem.

If the ruler measures 1-3/8", you have 7/16" diameter stem.

Paper Wrap Measuring


Measuring Grip Neck Stem

Measuring a Grip Neck Stem

Grip neck stems are most commonly used in wooden or metal tube furniture in conjunction with a socket. In most cases, if you measure the length of the stem and it is 1.5" long, you have a 5/16" diameter stem. If you are confident that is not what your stem measures, please measure it (or have it measured) precisely with a caliper or micrometer for length and diameter so we can find a match.


Threaded Stem and Thread Gauges

Measuring a Threaded Stem

Threaded stems require very specific measuring tools in order to find the correct diameter and thread pitch. Because of the many sizes and variations (metric, standard) the only way to be 100% confident of the measurement is to use a thread gauge. Pictured below is a thread gauge and threaded stem. If you don't have your own thread gauge, most hardware stores will be able to help you. Also, remember that we can measure your caster stem for you if you send it to us! (See top of page.)

Measuring With Thread Gauge