As for the rear shaft nut, I find torques that vary from 350ft lbs (475nm) to 550ft lbs (745nm - quite a difference btw), but I can't seem to find what the common torque is applied on the front spindle nut....
Anybody?
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the bearing design of the front versus the rear are different.
the rear two bearings inner races are held apart by a solid sleeve and thus the nut torquing is to clamp the two races to the sleeve. the inner and outer race are held together by the roller elements and the torquing has NO effect on the "loading" of the two bearings
the front two bearings are tappered design and the inner and out race have to be held together by the torquing of the nut. If the nut is over torqued even the slightest amount too much, it will over load the bearings
the rear two bearings inner races are held apart by a solid sleeve and thus the nut torquing is to clamp the two races to the sleeve. the inner and outer race are held together by the roller elements and the torquing has NO effect on the "loading" of the two bearings
the front two bearings are tappered design and the inner and out race have to be held together by the torquing of the nut. If the nut is over torqued even the slightest amount too much, it will over load the bearings
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The third drawing - that is inch lbs then, instead of pound foot like the first drawing?
the first hard torque is to ensure that the race/rollers have been seated with NO clearance for rotating.
then the nut is backed off and torqued just snug enough to hold together and allow rotation.
this is the method as found in many mechanic guides. the "just snug method" assumes the small amount of clearance needed is reestablished. You can see this method is not exacting and just as bad as too tight, being too loose can happen.
thus the "torque" is not the objective, setting the running clearance between the roller and the races is the desired. For the rear bearing design, the running clearance between roller and races is set during the bearing assembly.
I do want to clarify, I have NOT set a wheel bearing
then the nut is backed off and torqued just snug enough to hold together and allow rotation.
this is the method as found in many mechanic guides. the "just snug method" assumes the small amount of clearance needed is reestablished. You can see this method is not exacting and just as bad as too tight, being too loose can happen.
thus the "torque" is not the objective, setting the running clearance between the roller and the races is the desired. For the rear bearing design, the running clearance between roller and races is set during the bearing assembly.
I do want to clarify, I have NOT set a wheel bearing
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No worries, I do know a thing or two about bearings 
If the third drawing is indeed in inch pound lbs, that would be only be 1.25ft lbs, or 1,69nm, a bit too little I'm afraid. 10ft lbs (13,5nm) to 15ft lbs (20nm) sounds more reasonably.
I'll compare that to what I can dig up here...
If the third drawing is indeed in inch pound lbs, that would be only be 1.25ft lbs, or 1,69nm, a bit too little I'm afraid. 10ft lbs (13,5nm) to 15ft lbs (20nm) sounds more reasonably.
I'll compare that to what I can dig up here...
I did a little googling yesterday looking for setting tapered bearing .
here is an interesting one from Timpken (truck wheels though)
Basically torque it HARD to seat the bearing.
back it off and torque it hard
back it of a flat and verify ~0.001 endplay
http://www.timken.com/en-us/so...tment-procedures.pdf
and an intersting collection workshop procedures for several different vehicle makes (doesn't specifiy bearing design)
http://vintage.mitchell1.com/P...chis73/V2I738050.pdf
from a bearing design aspect, these recomendations appear to favor endplay, where I would agree a "cold" preload would be better.
here is an interesting one from Timpken (truck wheels though)
Basically torque it HARD to seat the bearing.
back it off and torque it hard
back it of a flat and verify ~0.001 endplay
http://www.timken.com/en-us/so...tment-procedures.pdf
and an intersting collection workshop procedures for several different vehicle makes (doesn't specifiy bearing design)
http://vintage.mitchell1.com/P...chis73/V2I738050.pdf
from a bearing design aspect, these recomendations appear to favor endplay, where I would agree a "cold" preload would be better.
From my experience with bearings, tapered roller bearings need minimal free play <.005" when set.
For spherical roller bearings you need a loose clearance for them to operate properly.
For front wheel bearings on a vehicle I have always spun the rotor/drum while tightening the spindle nut, applying about 15-20 ft lbs of torque to the nut. Back off the nut, then turn back till it just touches the bearing. Then lock down.
Jeff
For spherical roller bearings you need a loose clearance for them to operate properly.
For front wheel bearings on a vehicle I have always spun the rotor/drum while tightening the spindle nut, applying about 15-20 ft lbs of torque to the nut. Back off the nut, then turn back till it just touches the bearing. Then lock down.
Jeff