Bearing slip

HowieE · 07-20-2009, 11:03 AM

It is clear that the inner race of both bearings move on the spindle at some point in time. My question is when and why?

This clearly can not happen on a pressed on bearing but why does it happen on a slip on bearing? You would think the load on te race would hold it in place.

ROBERT CROSS · 07-20-2009, 11:34 AM

The bearing race is pressed on the spindle and should not spin.
If the wheel bearings have been re-packed and the bearings re-installed on the wrong race that COULD cause your problem. Bearings should ALWAYS be re-installed on the race they came off of.

To be safe dis-assemble and re-pack one at a time...old school.

2dogtraveler · 07-20-2009, 11:37 AM

I've owned three trailers and had the same happen on all at one time or another. It's a good question?

2dogtraveler · 07-20-2009, 11:49 AM

Are we talk apples and oranges? The race is pressed into the hub and is not moving. It's the inner part of the bearing moving on the spindle.

ArtStream · 07-20-2009, 12:27 PM

Quote:

Originally Posted by 2dogtraveler

Are we talk apples and oranges? The race is pressed into the hub and is not moving. It's the inner part of the bearing moving on the spindle.

"That would be the inner race"

ROBERT CROSS · 07-20-2009, 12:42 PM

Quote:

Originally Posted by ArtStream

"That would be the inner race"

Yep inner...my oversight.

But assembly is the same, match bearing and race.

HowieE · 07-20-2009, 02:00 PM

Let me clear things up a bit.

The INNER RACE of a slip on bearing is what I am referring to and yes they do turn on the spindle. My question is why?

As noted above with a pressed on bearing on shaft this would not happen.

ROBERT CROSS · 07-20-2009, 02:49 PM

Howie,
I am not familiar with a press on inner bearing. How would you install the inner seal?

Both races are pressed into the hub. The inner bearing should slide snugly over the greased spindle, it is kept from turning by the bearing preload. The spindle should be replaced if scored badly, or the bearing is too loose. If an inner bearing overheats it can get "welded" on the spindle and will pull apart when the wheel is removed.

dwightdi · 07-20-2009, 09:19 PM

You should not be preloading the bearings. The specification is to have them with 0.001 to 0.005 inch end play. That translates to just a feel of just the tiniest motion if you rock the wheel perpendicular to the axle. That means you bring them up snug by hand and back them off to the next notch. The inter races are fairly snug (0.002 - 0.005 loose) but should be able to turn. There should be no heat build up because they do not turn that fast and there should be less that 150F temperature build up due to friction at high speeds on the road from supporting the trailer. Discoloring does not occur below 400F. Blue color does not develop until over 600F. If you have any discoloring you have done something wrong and way over tightened the bearing.

ROBERT CROSS · 07-20-2009, 09:44 PM

Quote:

Originally Posted by dwightdi

You should not be preloading the bearings

Say what?.....http://www.pirate4x4.com/tech/billav...20pre-load.pdf

Mexray · 07-20-2009, 10:29 PM

I think it's important we're all on the same page here...

Tapered roller bearings - the kind in our trailer wheel hubs - consist of:

1. Tapered roller bearing assembly - cone shaped - called by mechanics, the CONE.

2.. Bearing cup - to accept the CONE assembly - called the CUP.

The CUPs are intended to have a press fit into their part of the assembly - the wheel hub - are aren't meant to move once installed.

The CONEs are intended to slide onto the axle shaft with a close tolerance, and are held in place with the outer wheel bearing pre-load by the nut/washer, etc.

We all know this stuff - let's just get on the same page and call em' CUPs and CONEs...to avoid confusion...

I believe most spinning CUP problems occur due to wear causing the CONEs becoming loose to the point of overheating and distorting the CUPs enough to loosen up, also lack of lube and improper adjustment are probably the chief culprits...

As some have mentioned before...once the CUP becomes loose, it's time to replace the wheel HUB/DRUM! It's just not cost effective to try and fix em' - they're too cheap!

ROBERT CROSS · 07-21-2009, 06:34 AM

Quote:

Originally Posted by Mexray

I think it's important we're all on the same page here...

Tapered roller bearings - the kind in our trailer wheel hubs - consist of:

1. Tapered roller bearing assembly - cone shaped - called by mechanics, the CONE.

2.. Bearing cup - to accept the CONE assembly - called the CUP.

The CUPs are intended to have a press fit into their part of the assembly - the wheel hub - are aren't meant to move once installed.

The CONEs are intended to slide onto the axle shaft with a close tolerance, and are held in place with the outer wheel bearing pre-load by the nut/washer, etc.

We all know this stuff - let's just get on the same page and call em' CUPs and CONEs...to avoid confusion...

I believe most spinning CUP problems occur due to wear causing the CONEs becoming loose to the point of overheating and distorting the CUPs enough to loosen up, also lack of lube and improper adjustment are probably the chief culprits...

As some have mentioned before...once the CUP becomes loose, it's time to replace the wheel HUB/DRUM! It's just not cost effective to try and fix em' - they're too cheap!

Thank You....'ya hit the rivet right on the head.

dwightdi · 07-27-2009, 06:17 AM

Spinning cups are a no no. Slight rotational movement of the cones on the shafts is unusual but not a problem. There should no color developed on any bearing surfaces. Most tapered roller bearing fail due to improper maintenance. This includes: contamination, improper mixtures of greases, over or under tightening or adjusting the preload, lack of grease, and fatigue life of the bearing materials. Airstream does not recommend preloading the bearings that come on your trailer. In an idea situation some minor preloading can be beneficial but the in the field experience has been that many more failures have occurred due to people not properly controlling the preload and over torquing the bearing, resulting in early failures. Therefore, Airstream has not recommended preloading the bearings. Here is a helpful how to from the Nevada unit.

Maintaining your RV- Wheel Bearing Maintenance