The load on the bearings will depend on the type of bearing you are working with. If you are working with ball bearings it is especially important that you pay attention to side load. Tapered bearings have a travel tolerance from side to side and will usually have an inner spacer that can be machined to give the proper tolerance when the bearings have been loaded. Ball bearings often have a spacer that is sized by the OEM to achieve proper spacing to make sure you do not side load the bearings. If you have an axle that is spinning freely inside a tight bearing then in my opinion you have a problem and should replace the bearing and at the very least check the axle to be sure it has not worn down from the bearing spinning on it. I used a magnetic based dial indicator and made a fixture using all thread to load tapered bearings when installing new bearings in my Drag Speacialty 18" spoke wheels on my last bike. (96 FLHR) I bench checked the side travel and then also double checked the travel once the wheels were installed on the bike with the same indicator. I recently traded off the bike and had put appx 40 thousand miles on the bearings with no problems at all. Refer to your service manual for proper procedures for your bike. If you are not confident you can handle the job then pay some one who is to do it for you. You do not want to take chances with your wheel bearings. For the record I am not a Harley trained mechanic. This is just my 2 cents based on personal experience. added the pic just cause I Loved that old bike!