How to Measure a Bearing
No vernier caliper? No Problem a ruler will do the job.
Remember most bearings sizes are full mm or inch sizes. eg: 9.53mm would be 3/8 inch.
If you measured at 9.5mm its probably an inch sized bearing.
To measure the bore of a bearing you can use a vernier caliper like the one shown. Insert the outer anvils of the caliper into the bore as shown and open the caliper until the bearing and caliper are a good fit about each other. Now read the value on the caliper. In the absence of a caliper a good quality steel ruler will suffice.
To measure the outside diameter of a bearing place the jaws of the caliper around the bearing and close it until its a good fit but not tight, now read the value from the caliper.
In the same manner as you measured the outside diameter measure the width as shown.