2016 Evo Front Wheel Bearing Spacer - Simple Tube?

[mcman56]

Is the front wheel bearing spacer on a 2016 Evo just a simple tube or are there countersinks on the ends.  The pics I see on line look like simple tubes.  Would anyone know the exact length? 

 

Mine has countersinks on the ends that match the inner ring and sort of a bulging ring on the ends of the ID.  Could this be correct?  See pictures.

To pull the front wheel from my Evo for a tire change, I had to use a hammer to get the axle out of the wheel.  I never had to do that on this bike before and there is no corrosion.  The bearings were crunchy feeling but there was no place to use a driver so I had to remove the inner race from one side to drive the bearings out.  These are the original bearings, made in France.  The bearings were greased so not a rusty failure mode.  The spacer still will not slide over the axle from either  direction.  It does not look like the bulges on the ID were machined.  It sort of looks like the countersinks on the ends and the bulges were formed by crushing the spacer but is that even possible?  Strange    

 

 

Edited January 13 by mcman56
add detail

[konrad]

This is yet another example of the kinds of problems I see with all trials bikes.  Even if the design is okay, the end result can easily be compromised by poor manufacturing and assembly.

The soft alloy spacer was crushed when the wheel bearings were installed at the factory.  The condition may have been helped along by a gorilla tightening the front axle.

Even Honda/Montesa is not immune to this.  While changing handlebars on my 4RT, I inadvertently swapped clamps for the master cylinders.  Those parts should have identical dimensions, but they would not interchange.

[mcman56]

From your answer, I take it that the spacer should be a simple tube so I ordered a new one.  It seems odd that the issue just showed up now.  I use a torque wrench.  It has over 200 hours on the bike.  Maybe an original crush at the factory plus tiny moves at the axle tightening finally made it tight on the axle.  I took some measurements and the spacer without counterbore is the correct length.  The pressed in counterbores are 0.016" deep each.  It seems odd that a bearing would take that kind of side load for a long time.  The bearings are pretty small.  The shoulder on the inner race is particularly small in area where is presses on the spacer..  The spacer does look like some kind of extrusion and I was tempted to make one of 6061 but I would have to order material for that too.

Do you think the manufacturers all make their own wheels?  Most of the bikes come from a small part of the globe so I wonder if they all get their wheels made at tahsame place.

         

[konrad]

Wow, 0.016" at each end!?  So the spacer is like 0.8mm longer than it should have been!?  Or the bearing pockets were bored that much deeper than they should have been?  Maybe the manufacturer changed the hub dimensions without changing the spacer spec? 

The purpose of the spacer is to ensure there is no (or very little) axial load on the bearings.  I doubt it is an extrusion. I would assume it was made from tubing.

My guess is that most trials manufacturers buy wheels already assembled.  But Beta is a big company and may be different. 

Edited January 13 by konrad
Fixed ma spellin'

[mcman56]

Per my measurements, the non counterbored spacer is the correct width for this particular hub.  I have ordered a new one and will verify its size.  That brings up the question of how the counterbores got pressed in.  I do not think an inner race could be moved 0.016" without destroying the bearing.  Even if it did not destroy the bearing, I would expect it to fail immediately.  The ring of interface between the bearing inner race and spacer is only about 1 mm wide.  I would like to understand before installing all new parts and having it lock up.

I have high confidence in my measurements but they may not be perfect.  I could get an outside mic on the hub and used a depth mic for the bearing counterbores.  They are rather thin and have a corner radius so not easy to measure but the number I found was the same width as the bearing.  Maybe something is wrong with one of the bearings.  To get this apart, I had to rip the cages from one bearing to remove the balls and inner race but I can take a look.    

   

   

[Tr1AL]

28 minutes ago, mcman56 said:

Per my measurements, the non counterbored spacer is the correct width for this particular hub.  I have ordered a new one and will verify its size.  That brings up the question of how the counterbores got pressed in.  I do not think an inner race could be moved 0.016" without destroying the bearing.  Even if it did not destroy the bearing, I would expect it to fail immediately.  The ring of interface between the bearing inner race and spacer is only about 1 mm wide.  I would like to understand before installing all new parts and having it lock up.

I have high confidence in my measurements but they may not be perfect.  I could get an outside mic on the hub and used a depth mic for the bearing counterbores.  They are rather thin and have a corner radius so not easy to measure but the number I found was the same width as the bearing.  Maybe something is wrong with one of the bearings.  To get this apart, I had to rip the cages from one bearing to remove the balls and inner race but I can take a look.    

   

   

@mcman56 As this all worked at some point previous to this happening  you could grind or file the crushed inner edges of the spacer tube at both ends until the axle passes through it again and then grease it all up put some new C3 wheel bearings in and tighten the axle up by hand no torquing no excessive tightening needed then   push on the suspension a few times to centralise everything  and then tighten the pinch bolts to clamp/lock up the spindle/axle bolt.

[mcman56]

I disassembled the second bearing and the inner race is cracked.  You can also see stress marks in the ball area of the matching outer race so maybe the cracked race allowed things to move around.  I did use an expanding anchor to try and remove one of the bearings so possibly could have cracked the race but that would not explain the stressed out race. I have never seen a crack like this before.  

 

 

Edited January 15 by mcman56

[konrad]

Are there markings on the bearing to indicate its manufacturer?

I searched the 2016 Evo parts diagrams.  Seems the wheels are Morad (but the parts list misspells it as Monrad).

Did you heat the hub when you removed the bearings?

Your diagnosis will be better than most because you know all the history.

[mcman56]

I did heat the hub but was not careful with the old bearing.  It is marked SKF France.

[konrad]

So we have an Italian motorcycle with Spanish wheels and French bearings.

My bet is that the damage was done at the time the bearings were first installed.  Something did not fit properly, but it just got pressed together anyway.  Use and wear (and possibly disassembly) exacerbated the problem.

As I said previously, you are in the best position to guess what happened.  All the forum can do is provide some hints.

 

[lemur]

Looks like a lighter duty bearing compared to what my trials bikes use.   In my experience if bearings fly to pieces on removal that is usually because they were left too long before being replaced.