(10-17-2020 )Rawze Wrote: (10-16-2020 )bwake Wrote: ...
A wheel bearing will actually last longer if there is a small amount of pre-load on it but there is no possible way for a person to test pre-load in a verifiable manner.
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Pre-load is measured in length (inche or metric). Pre-load can easily be measured (non-sleeved bearings) by simply using a dial indicator. Whoever told you this is mis-informed and don't know squat about applying standard pre-load tightening methods on industrial machinery.
While there is still back-lash on the system, measure and determine how far to turn the tightening nut to remove 0.001" of backlash (assuming everything is clean and measurements are accurate). This shows how far to turn the nut for every 0.001" of pre-load. -- Then while tightening, and there is no more backlash and all play is removed, add the required amount of pre-load by turning the nut however many 0.001" more.
I have done this many times with people who have come over here with sleeveless hubs that want to learn how to pre-load their sleeveless bearings properly using a dial indicator. - Most of the time it equates to roughly about 50 - 70 ft-lbs of torque on the bearing nut (i.E.> the old addage that mechanics sometimes use of tightening the nut to 50-70 ft-lbs on sleeveless hubs and is also stated as such in some hub bearing manuals). Using torque alone to set pre-load is not accurate though, and on some of the larger spindle hubs, it can be much higher than 70 ft-lbs... hence measuring it accurately like mentioned.
Of course, this also assumes someone has seated everything properly by tightening the assembly up at maximum component torque to seat everything first, then releasing it. That step is very important to ensure all bearing races are properly seated + the inner bearing race that mates to the spindle is press-fit with proper pressure so that it does not spin later agiast the spindle and chew it up.
On another side note that is related ... for dump-truck and heavy haul guys out there who are using sleeveless hub bearings ... Loc-tite-609 is your friend on a spindle where the bearing race sits on the spindle when it comes to severe duty/exceptionally high load applications. Spindle galling and/or failure can be avoided on sleeveless bearings if things are installed properly + 609 is used to help prevent slippage under heavy side-loading of the hub.
While I don't disagree with your statement, it could easily get an untrained person into some hot water based on the fact that there is no way to verify by measurement that it was done correctly, once finished. 10 in lbs and 100 ft lbs will all show no end play on a dial indicator. For someone that doesn't understand what they are doing, this could be a catastrophic mistake. This is the reason they recommend .001 to .005 as a final end play, it's a measurable specification that ensures that it isn't over torqued.
