How wide are the stems on this product? I am looking to replace smaller casters with a product that has more height but want to make sure they fit in the whole.

This caster is designed for use with the Lakeside Round Post 3-Side Enclosed Wire Shelf Carts - it is not marketed for use in any other application. As such, the manufacturer does not provide the stem width information. Are you planning to use this caster with a Lakeside cart?