There are 4 key parameters that have to be right — elevation, distance, levelness, and square.
Ever stood on a pitching mound and noticed the rubber was twisted? While most might think that it is not a big deal, ask a pitcher, a pitching coach, or a trainer how even a minor twist can have major effects on a pitcher’s mechanics.
A pitching rubber that is just slightly turned by ¼” on a Major League mound will move the centerline off-center from home plate by 1.15°, or 14½”. A rubber that is twisted just a little more to a ½” will throw the centerline off by 2.39°, or more than 2 ½ feet! That messes with a pitcher’s mechanics and increases wear on their arm as they work to compensate for the misalignment.
The the apex of home plate is the benchmark of a ballfield. Everything is laid out based on its placement. The pitching mound and its rubber are equally critical for a pitcher.
These four parameters require absolute perfection in order to successfully install a pitching rubber to specification. Elevation, distance, levelness, and square are interdependent. Adjusting any one of these four parameters will require you to check the other three to ensure they are still correct.
To accurately determine if the pitching rubber is square, you’ll need to measure from the square portion of home plate. On the rubber, measure 8½” in both directions from the centerline and mark those points on the front of the rubber (see illustration). Using the Measurements Table (right), find the pitching distance for your ballfield and reference the squaring measurement.
Measure the distance from the front square corner of home plate to the front of the pitcher’s rubber at the 8-½” mark you made earlier. Repeat this measurement on the other side, from the opposite corner of home plate to the front of the pitcher’s rubber. These measurements should be the same when home plate is square to the pitching rubber.
If these measurements are not the same, then the pitching rubber needs to be adjusted by twisting it slightly until the measurements match. Each time you manipulate the rubber to bring it square, re-measure the pitching distance and the two squaring measurements on each side of the rubber until they all meet the specified distances shown on the Measurements Table.
When all four of the parameters have been met — elevation, distance, levelness, and square — double-check each measurement one last time before backfilling around the rubber. After compacting around the rubber, do one final check on level, distance, and square to ensure the compacting process did not throw the rubber off its mark.
Installing a pitching rubber can be tedious. It is one ballfield task that demands both accuracy and patience. It can take as little as 15 minutes to set the rubber, or it can take as much as an hour. In either case, perfection is your ultimate goal.