Abstract: An adjustable bearing spacer (12) includes a cylindrical outer body (42) having a first end (44) for abutment with a bearing cone (28) disposed within one end of a hub (10) and an adjustable ring (46) for abutment with an opposite bearing cone (30). The ring (46) is threadingly engaged with the outer body (42) so as to be extendable from an end (48) of the body (42) allowing adjustment of the length of the spacer (12). End (48) is provided with a plurality of evenly-spaced markings. Two of these markings are in the form of small holes into which the prongs of a tool can be inserted. End (58) of ring (46) is also provided with markings in the form of holes into which the prongs of a tool can be inserted. The markings form an indexing scale for providing an indication of the extension in the length of the spacer (12) when the ring (46) is screwed in or out. The degree of extension is calculated as follows E11=1/x.