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Discussion Starter · #1 ·
I installed new Honda OEM (Nachi) front wheel bearings (CX500D, 1980)....



First in was the right side with outer bearing race seated fully to its shoulder in the hub as per manuals. Inserted "distance collar", a bit of grease etc then seated remaining bearing fully to its shoulder.



Bummer... inner races on both bearings now TIGHT, not rotating at all. Drove out (trashed) both new bearings. Measurements were taken and the "distance collar" is about .012" to 015" longer than the distance between the outer race seating shoulders in the hub.



I measured another wheel hub and its "distance collar"..... same result.



Is there supposed to be a "preload" upon installation for a single row ball bearing assembly? I can understand such for tapered roller bearings as in autos where there is a lot of side thrust to deal with. But .012"-.015" seems like way too much, so much that the "distance collar" could not be moved sideways except with a hammer/drift.



Hoppy



PS... Another set of new bearings are on the way (It's enough to pi$$ the Pope off)
 

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Discussion Starter · #3 ·
The new bearing part is Honda 96120-6302010 (Nachi 6302ZE), metal shield, one side.



The original bearings taken out were Koyo 6302Z, metal shield, one side.



Inner and outer races for both measure .510"



I can't think of anything being amiss inside the hub. All that goes in there between the bearings is the "distance spacer". I thought it possible that I may have "cocked" the spacer but before removing the bearings I made sure it was aligned by passing the axel bolt thru. It remained bound up.



Maybe the grease must be yellow as original and not red?



Hoppy



PS.. Not so pi$$ed now that I know SHEP is alert and thinking.
 

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Is it possible that one of the old wheel bearing shields came off and has been left in the recess?



I only use the RS type bearings which means they are fully sealed.I took to the old single sided ones out years ago.



This will Piss you of<grin>.



http://cgi.ebay.com/2-6302-2RS-New-...394?pt=LH_DefaultDomain_0&hash=item5ad8a095c2



Get some 500+ wet and dry and polish the inner face of the bearing recess so the bearings slip in easy with a bit of oil/grease on the outer face.They should not have to be forced,just gently tapped in and a snug fit.I use a piece of flat wood and a Rubber camping mallet.
 

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Discussion Starter · #5 ·
Is it possible that one of the old wheel bearing shields came off and has been left in the recess?



I only use the RS type bearings which means they are fully sealed.I took to the old single sided ones out years ago.



This will Piss you of<grin>.



http://cgi.ebay.com/2-6302-2RS-New-...394?pt=LH_DefaultDomain_0&hash=item5ad8a095c2



Get some 500+ wet and dry and polish the inner face of the bearing recess so the bearings slip in easy with a bit of oil/grease on the outer face.They should not have to be forced,just gently tapped in and a snug fit.I use a piece of flat wood and a Rubber camping mallet.


Nothing in the recess. Some clarification..... What's happening is the inner races are contacting the "distance spacer" about .012"-.015" before the outer races contact the seating shoulders in the hub. Rusult: excessive (to me) pre-load and bound up inner races.



Hoppy
 

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Hmmm....



I assume it was rotating ok before the new bearings?



As the inner spacer is only a Guide IMHO I'd be tempted to grind a bit off.Maybe there's a manufacturing difference in thickness/design.Only guessing here.Just to clarify.When you nip up the axle the wheel is binding yes?
 

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Discussion Starter · #7 ·
Hmmm....



I assume it was rotating ok before the new bearings?



As the inner spacer is only a Guide IMHO I'd be tempted to grind a bit off.Maybe there's a manufacturing difference in thickness/design.Only guessing here.Just to clarify.When you nip up the axle the wheel is binding yes?


Bearings were rotating OK before the new install. But they were old and just a bit sloppy. I did not mount the new assembly in the forks before running off into the "well,... tear it back apart mode".



Grinding off the spacer a bit sounds like a good fix IF, in this design, there is not meant to be positive contact between the inner races and the "distance spacer" when things are all torqued/squished together.





Hoppy
 

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Bearings were rotating OK before the new install. But they were old and just a bit sloppy. I did not mount the new assembly in the forks before running off into the "well,... tear it back apart mode".



Grinding off the spacer a bit sounds like a good fix IF, in this design, there is not meant to be positive contact between the inner races and the "distance spacer" when things are all torqued/squished together.





Hoppy


I changed some bearings last year or the year before and I'm sure the inner spacer is more of a guide for the axle and I'm almost certain it moved freely when the bearings were in.If you think about it the bearings cannot go any further than the inner seat but their centres obviously want stopping from being forced further,too far in when nipped up.On the parts fiche it's called a Collar,distance.
 

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I changed some bearings last year or the year before and I'm sure the inner spacer is more of a guide for the axle and I'm almost certain it moved freely when the bearings were in.If you think about it the bearings cannot go any further than the inner seat but their centres obviously want stopping from being forced further,too far in when nipped up.On the parts fiche it's called a Collar,distance.






i also recently replaced my front wheel bearings in my gl500i and the spacer did move freely in mine.
 

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There are a ton of cheap Chinese imitation bearings floating around that have various problems, it's gotten so bad the bearing manufacturers have even banded together to fight this. Only buy from a local bearing shop even if they do cost a few pennies more, that way you know you'll be getting accurate, well built product.



Stop Fake Bearings: http://www.timken.com/en-us/Pages/Home.aspx



Learn More about the WBA: http://www.timken.com/en-US/about/N...nessCampaignAgainstProductCounterfeiting.aspx
 

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Discussion Starter · #12 ·
I'm wondering if, at the factory, bearings may have sometimes been installed with one fully seated and the opposite "just far enough". In other words, the outer races were not always seated to contact both hub shoulders as per the Haynes and Clymer manuals. The Honda factory manual says "fully seated". Maybe that really means "make an adjustment as necessary". A dirty little manufacturing secret from long ago. A problem with some tolerances with seating shoulders in the hubs.



I don't consider this thread dead yet so anyone with comments... please do so.



Hoppy
 

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It's possible you may be right, the bearings aren't fully flush even when properly installed.



Do you remember how the old ones looked?
 

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Sounds odd.

I didnt have any probs when I changed mine last year

As the races tap into a shoulder, the only reason I can think

of to make them foul is either

The inner ring of the new bearing is thicker than the outer

but that shouldnt happen

or

The spacer is dropping and the diagonal length being longer than the

axial length makes it prop against the bearing inner ring

perhaps if you set one bearing in, then poke the axle up from underneath

as you fit the other it will keep the spacer aligned?



If the spacer is too long why didnt it foul the old bearing?
 

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I will assume you're very carefully tapping them in with a deep socket to keep the pressure evenly distributed?
 

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Discussion Starter · #16 ·
I will assume you're very carefully tapping them in with a deep socket to keep the pressure evenly distributed?


Yup...I was careful. Still thinking and wondering why.



Hoppy
 

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I've had exactly the same problem, solved it by first putting in the bearing on the right side (as per the Honda manual) then tapping the other bearing in until the inner ring just lightly touched the spacer, then put in the axle and tightened nut on that to see if it would turn smoothly. Which simply means tapping it in only as far as needed.



The root cause must be tolerances in manufacturing. The only good way to use roller bearings is really to do some very carefull shimming in a wheel like this but that costs money which Honda doesn't want to spend. It would also be very unfriendly for maintenance, but I believe some BWMs and other bikes have an arrangement using conical roller bearings which must be adjusted very precisely.



I have seen some some Japanese bike wheels (early Suzuki I think) where C3 type bearings were used, meaning they intentionally have a bit more play than normal, that's the cheap way to do it BUT if you replace these C3 types with -say- nice new normal (non-C3)Swedish SKF bearings you may run into the problem we've had.



Anyway, bottom line : check manual for special procedures and in this case tap them in only as far as needed.



(and I managed to tap out only the one on the left, so only had to but one new)



cheers, Frans
 

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Discussion Starter · #18 ·
Hmmm....



I assume it was rotating ok before the new bearings?



As the inner spacer is only a Guide IMHO I'd be tempted to grind a bit off.Maybe there's a manufacturing difference in thickness/design.Only guessing here.Just to clarify.When you nip up the axle the wheel is binding yes?


I've been googling "ball bearing, preload" and have gleaned a little info (a little info is all my damaged geezer mind can absorb). Bearing design and application is a tremendously complex field so in the hopes that a little knowledge is not really all that dangerous here goes;



The following pic is deep groove single row ball bearing.













This appears to be what we have in CX wheels. The upper right lined/shaded area is the hub outer bearing contact surface. "Fa" I assume is force applied. The diagonal arrows indicated contact load/area. This "preload" is achieved by torqueing the axel nut to the proper spec.



There is no way to get a reliable preload if the "distance collar, spacer" is longer than distance between the hub outer bearing seating surfaces. I'm about to commit to shortening my "distance collar, spacer" as per your suggestion SHEP.



28000 miles on the old bearings and everything seemed like it was fine. Then I decide to change tires, find what I think is a little bearing wear and go opening a can of worms by getting into the bearings. Why do simple things have to get complex? It's a curse of some kind.



Hoppy
 

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Discussion Starter · #19 ·
I've had exactly the same problem, solved it by first putting in the bearing on the right side (as per the Honda manual) then tapping the other bearing in until the inner ring just lightly touched the spacer, then put in the axle and tightened nut on that to see if it would turn smoothly. Which simply means tapping it in only as far as needed.



The root cause must be tolerances in manufacturing. The only good way to use roller bearings is really to do some very carefull shimming in a wheel like this but that costs money which Honda doesn't want to spend. It would also be very unfriendly for maintenance, but I believe some BWMs and other bikes have an arrangement using conical roller bearings which must be adjusted very precisely.



I have seen some some Japanese bike wheels (early Suzuki I think) where C3 type bearings were used, meaning they intentionally have a bit more play than normal, that's the cheap way to do it BUT if you replace these C3 types with -say- nice new normal (non-C3)Swedish SKF bearings you may run into the problem we've had.



Anyway, bottom line : check manual for special procedures and in this case tap them in only as far as needed.



(and I managed to tap out only the one on the left, so only had to but one new)



cheers, Frans


Frans,



Thanks for the input Frans. Well stated. Now I don't feel so alone.



Hoppy
 

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As for the bearing preload, the only way to achieve it is similar to what you had going on in your original post. By having the center spacer be slightly longer than needed you can achieve a preload by pressing in the bearings far enough to get the correct preload force (not a good way to go about it IMPO). Since the Honda manual doesn't mention adjusting the preload I'd guess that wasn't the intent and it's just design faults that didn't get fixed (the techs fixed it by not pressing the bearings in all the way).



The preload force keeps the bearings always pressed against the race; that picture you posted is an excellent resource to understand how it works. I'd imagine having that preload force would improve handling and keep the front end firmer (less wobble), but it probably wouldn't be a noticable difference; especially with high-precision bearings. I'm uncertain whether bearings meant to be preloaded can suffer damage from being run without it (I may be a mechanical engineer, but I'm definitely no bearing expert).
 
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