J
Jim Beam
Guest
Ray Heindl wrote:
> [email protected] wrote:
>
>
>>Mike Jacoubowsky writes:
>>
>>>If you surmised that the bearings might have been destroyed due to excessive preload, wouldn't
>>>replacement of bearings be a requirement, not an option? Bearings cost so little compared to the
>>>time involved in overhauling a hub, I just can't find much rationale for not replacing them, even
>>>if everything seems OK.
>>
>>Bearing balls are far tougher than bearing races and if there are none available, they could be
>>reused if they are still shiny. That could be because the races crack and spall, like an asphalt
>>street that has been cracked from heavy traffic.
>
>
> I've seen spalled cones, but never the cups. Are the cups made tougher because they're more
> expensive to replace, or is it because they're loaded differently, or have I just been lucky?
please, someone do the math, but this is the situation as i understand it:
on the outer race, you have a concave surface, with a ball whose radius is smaller, but oriented in
the same direction from perpendicular. this gives the maximal race/ball point contact area. with the
inner race, the radiuses are oriented opposite so the point contact area between race & ball is
minimal. and as the contact area tends to zero, the point stress rises to infinity. if the point
contact stresses are greater on the inner race than the outer, it stands to reason that the inner
race will spall sooner.
> [email protected] wrote:
>
>
>>Mike Jacoubowsky writes:
>>
>>>If you surmised that the bearings might have been destroyed due to excessive preload, wouldn't
>>>replacement of bearings be a requirement, not an option? Bearings cost so little compared to the
>>>time involved in overhauling a hub, I just can't find much rationale for not replacing them, even
>>>if everything seems OK.
>>
>>Bearing balls are far tougher than bearing races and if there are none available, they could be
>>reused if they are still shiny. That could be because the races crack and spall, like an asphalt
>>street that has been cracked from heavy traffic.
>
>
> I've seen spalled cones, but never the cups. Are the cups made tougher because they're more
> expensive to replace, or is it because they're loaded differently, or have I just been lucky?
please, someone do the math, but this is the situation as i understand it:
on the outer race, you have a concave surface, with a ball whose radius is smaller, but oriented in
the same direction from perpendicular. this gives the maximal race/ball point contact area. with the
inner race, the radiuses are oriented opposite so the point contact area between race & ball is
minimal. and as the contact area tends to zero, the point stress rises to infinity. if the point
contact stresses are greater on the inner race than the outer, it stands to reason that the inner
race will spall sooner.