Final Driven Flange bearings: I'm so confused.......

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Thank you gentlemen (and maybe some ladies) for the helpful input on other Flange Bearing postings.......EXCEPT for "OEM or not to OEM"....that is the question.

I'm not a wealthy man, but best friend/mechanic said that when it comes to HONDA parts, "buck up and pay for the OEM". But the posts on HONDA bearings VS aftermarket, old off the shelf or brand new from China.....leave me questioning what, and from who should I purchase. Let me add that I am a novice at repair jobs, and have never repacked bearings, so I'd kind of like to avoid that project. SO............

1. If I go with OEM.....should I purchase from one of the big houses on line (BBandit or Chapperal) with the hope that greater turn over on parts means newer stock , or another online option, or go to the local HONDA shop? Or aftermarket options?
2. Is there an "off the shelf" Molydbenum Disulfide Paste that you might recommend, or just "buck up"and get the HONDA?
3. I checked the 6204 on the disk side replaced 10K ago and the primary bearing also 10k old and both smooth as glass, and shaft has a light shadow where the flange bearings are, but otherwise in fine shape.
3. When replacing the bearings into the flange, how much Moly paste should be applied to the bearings.....a little, medium or smothered, or none?


Thanks for the time and any response! Merry Christmas and happy holidays........it will be a while before we are back on the road here in Southern Colorado as there is still some snow and ice on the roads, and enough sand to make a Motocross rider grin with glee.....:bow1:
 

dannyk

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I bought a pack of bearing from I think it was called (all balls) or something like that from off the internet, payed less for 10 than what mother honda wanted, for a set. Still have a couple left after rebuilding a friends once mine a couple of times. I now just pull the seal from one side and repack with general purpose grease and reinstall the seal. All purpose grease on the axel lightly, and molly on the teeth, Never seen an axel that didn't have the shadow on the axel where the flange bearings ride. (93k on mine 4th set of flange bearings in it now) I bought the bearings with the seal on both sides, same bearing just two seals instead of one.
 
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I am just going from memory but all of your questions are probably addressed in the ST1300 - bearings forum.

What I did:
1. Go with aftermarket, sealed on both sides for the driven flange bearings. I buy Japanese or US made bearings.
2. Permatex makes one, it can be found on Amazon. Honda has a replacement that comes in a tube and is expensive.
3. Rear wheel bearings generally last a lot longer than front wheel. If smooth, leave them alone, especially at that low mileage. Mine are 97k miles old and still smooth. It is normal to have a "shadow" on the axle.

No need to put moly paste on the driven flange bearings.
The only places you need to put moly paste on the rear wheel are the wheel splines and with the driven flange removed at the driven flange / wheel bearing interface.
Put some on the drive splines too.
 

Mellow

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I did what Danny did... I just replaced them about every 2nd or 3rd tire change. If the OEM ones are so good, they wouldn't have issues. It's really one of the few Achilles heels that the ST1300 has, there are a few little nit picky things but this is about the only one that can leave you stranged. The U-Joint is another one but no easy way to check that so unless you are in the 80k mile range I wouldn't worry about it.. if you're lucky like I was I found my u-joint going out while messing with the bike in the garage.
 

Blrfl

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old off the shelf or brand new from China
They're bearings, not broccoli. They don't spoil in storage any more than they do while on your bike.

I am a novice at repair jobs, and have never repacked bearings, so I'd kind of like to avoid that project.
Fortunately for you, the bearings are sealed.

3. When replacing the bearings into the flange, how much Moly paste should be applied to the bearings.....a little, medium or smothered, or none?
Use the amount specified in the service manual, which is well worth the price of admission. (The answer is none; the moly paste goes on the splines when you reattach the rear wheel.)

--Mark
 

BakerBoy

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I work with bearings on high speed, high load, proprietary assemblies; we use almost exclusively SKF (occasionally Timken, Lufkin, NSK) and will NOT use a Chinese supplied bearing, no matter how much lower the cost. There are simply too many dimensions to get right and too much cost if a bearing doesn't last. There is a difference in bearing manufacturers.

You mention 6204--the left (disk side of the wheel) rear wheel bearing is a single 6204UU. The flange driven bearings are a pair of 6905RS bearings, mounted side by side, with each bearing's seal positioned to the outside face of the pair of bearings. I mention the bearing numbers only so that a reader of this thread doesn't mix the two.

Regarding the 6905 flange driven bearings: I put Honda-packaged OEM bearings in mine after a set of Honda factory-installed OEM bearings failed at <35,000 miles. (SKF doesn't make 6905 radial ball bearings, or I'd have tried them.) I proactively removed that second OEM set at ~25k miles and they were in good shape (but I tossed them anyway to avoid the temptation to use them longer). I replaced that second set with another Honda OEM set, and that 3rd set is still 'young' and installed.

Regarding the seals, some 6905 bearings are built as "-2RS" and others as "RS" (both sides sealed vs one side sealed). While I believe Honda specifies "RS", folks have used "-2RS" without issue. I think "-2RS" is a bit better (just my opinion). Honda species "RS" with the seals positioned on the outside of each bearing pair (therefore the inner, adjacent faces do not have seals between them)--this allows slighly more space for grease**. The problem is that if one bearing starts to fail and there's no inner seal, debris from within the failing bearing ends up in the still-good bearing--it will fail quicker than if a seal were there to keep the debris out.

**Never fill the entire space within a bearing with grease! Always replace ~1/2 of the bearing airspace with a good wheel bearing grease.

You'll likely hear replies from folks who've successfully used VXB bearings, ceramic bearings, double-wide needle bearings, etc. To each their own. :)

Specifically to your questions:

1. Honda's part number for their 6905RS bearing is 91052-KZ4-J21. Google it and you can find many places to consider buying it from (or to ask your dealer to get for you).

2. Never use moly disulfide paste within bearings. Such is not proper for bearing ball and raceway cooling and lubrication as paste doesn't have the correct properties--the moly paste becomes hardened moly 'cake', the bearing runs dry (runs hot), and has lumpy moly crumbs spinning inside it! Moly disulfide paste is only for parts with very slow relative motion, high-load surfaces like splines. For grease within a bearing, use a good name brand wheel bearing grease (parts stores have several to choose from).

3. No comment.

3. See #2 above! No moly paste in bearings! Only use moly paste on the splines.

Also, when you put the rear wheel back together, put a very light film of the bearing grease on the axle to avoid corrosion and to allow better heat transfer out of the bearings and collars into the shaft (you want to get heat out of the bearings to make them and the grease last longer).

Hope that helps...
 

Kevcules

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I work with bearings on high speed, high load, proprietary assemblies; we use almost exclusively SKF (occasionally Timken, Lufkin, NSK) and will NOT use a Chinese supplied bearing, no matter how much lower the cost. There are simply too many dimensions to get right and too much cost if a bearing doesn't last. There is a difference in bearing manufacturers.

You mention 6204--the left (disk side of the wheel) rear wheel bearing is a single 6204UU. The flange driven bearings are a pair of 6905RS bearings, mounted side by side, with each bearing's seal positioned to the outside face of the pair of bearings. I mention the bearing numbers only so that a reader of this thread doesn't mix the two.

Regarding the 6905 flange driven bearings: I put Honda-packaged OEM bearings in mine after a set of Honda factory-installed OEM bearings failed at <35,000 miles. (SKF doesn't make 6905 radial ball bearings, or I'd have tried them.) I proactively removed that second OEM set at ~25k miles and they were in good shape (but I tossed them anyway to avoid the temptation to use them longer). I replaced that second set with another Honda OEM set, and that 3rd set is still 'young' and installed.

Regarding the seals, some 6905 bearings are built as "-2RS" and others as "RS" (both sides sealed vs one side sealed). While I believe Honda specifies "RS", folks have used "-2RS" without issue. I think "-2RS" is a bit better (just my opinion). Honda species "RS" with the seals positioned on the outside of each bearing pair (therefore the inner, adjacent faces do not have seals between them)--this allows slighly more space for grease**. The problem is that if one bearing starts to fail and there's no inner seal, debris from within the failing bearing ends up in the still-good bearing--it will fail quicker than if a seal were there to keep the debris out.

**Never fill the entire space within a bearing with grease! Always replace ~1/2 of the bearing airspace with a good wheel bearing grease.

You'll likely hear replies from folks who've successfully used VXB bearings, ceramic bearings, double-wide needle bearings, etc. To each their own. :)

Specifically to your questions:

1. Honda's part number for their 6905RS bearing is 91052-KZ4-J21. Google it and you can find many places to consider buying it from (or to ask your dealer to get for you).

2. Never use moly disulfide paste within bearings. Such is not proper for bearing ball and raceway cooling and lubrication as paste doesn't have the correct properties--the moly paste becomes hardened moly 'cake', the bearing runs dry (runs hot), and has lumpy moly crumbs spinning inside it! Moly disulfide paste is only for parts with very slow relative motion, high-load surfaces like splines. For grease within a bearing, use a good name brand wheel bearing grease (parts stores have several to choose from).

3. No comment.

3. See #2 above! No moly paste in bearings! Only use moly paste on the splines.

Also, when you put the rear wheel back together, put a very light film of the bearing grease on the axle to avoid corrosion and to allow better heat transfer out of the bearings and collars into the shaft (you want to get heat out of the bearings to make them and the grease last longer).

Hope that helps...

great explanation!
 
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I work with bearings on high speed, high load, proprietary assemblies; we use almost exclusively SKF (occasionally Timken, Lufkin, NSK) and will NOT use a Chinese supplied bearing, no matter how much lower the cost. There are simply too many dimensions to get right and too much cost if a bearing doesn't last. There is a difference in bearing manufacturers.

Also, when you put the rear wheel back together, put a very light film of the bearing grease on the axle to avoid corrosion and to allow better heat transfer out of the bearings and collars into the shaft (you want to get heat out of the bearings to make them and the grease last longer).

Hope that helps...
Very thorough, and complete reply!

Some years ago, when buying bearings for a power tool at Bearings Incorporated - now Applied Industrial Technologies (did they ever screw up renaming/rebranding their company or what!?) the counter guy explained to me the difference between Tier 1, Tier 2, and Tier 3 bearing companies. If I have it right, the companies named above are all Tier 1 - i.e. they make about as good a bearing as you can buy. I'm not knowledgeable about bearings, but I generally will buy, like John, from these manufacturers. Most of the time the more expensive part is not that much more than the cheap one, and if it saves me tearing the bike apart a second time, it is well worth it. Ymmv.

And, I did not know that about grease promoting heat transfer away from the bearings to the axle. I'd always assumed the grease on the axle was to prevent corrosion and subsequent problems from that. Steel expands, I think, 17 times in volume as it rusts, which is why a rusted shaft freezes in its bearing/bushing/machined hole. A bit of grease on the axle will thus serve at least two functions.
 

dduelin

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I work with bearings on high speed, high load, proprietary assemblies; we use almost exclusively SKF (occasionally Timken, Lufkin, NSK) and will NOT use a Chinese supplied bearing, no matter how much lower the cost. There are simply too many dimensions to get right and too much cost if a bearing doesn't last. There is a difference in bearing manufacturers.
Do the driven flange bearings actually meet any of these criteria requiring bearings of the highest quality or is the quality bearing here one that meets standards much less stringent? The flange bearings do not support the weight of the bike on the axle, the spline loads and rotational speeds are low, ST1300s simply do not wear out splines if kept correctly greased, and there is absolutely no history of dangerous or expensive catastrophic final drive failures even if ST1300s are operated for long periods with toasted driven flange bearings. My OEM bearings served until 96,000 miles and a set of Peer bearings sourced at that time have served the last 70,000 miles. I remove the collar and separate the bearings for inspection every tire change but I suspect no bogey man hiding in the FD requiring anything other than OEM or inexpensive aftermarket bearings.
 

BakerBoy

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Do the driven flange bearings actually meet any of these criteria requiring bearings of the highest quality or is the quality bearing here one that meets standards much less stringent? The flange bearings do not support the weight of the bike on the axle, the spline loads and rotational speeds are low, ST1300s simply do not wear out splines if kept correctly greased, and there is absolutely no history of dangerous or expensive catastrophic final drive failures even if ST1300s are operated for long periods with toasted driven flange bearings. My OEM bearings served until 96,000 miles and a set of Peer bearings sourced at that time have served the last 70,000 miles. I remove the collar and separate the bearings for inspection every tire change but I suspect no bogey man hiding in the FD requiring anything other than OEM or inexpensive aftermarket bearings.
Yes, highest quality bearings will have effect. And so will proper fit of the mating parts. But sadly, we don't know what the proper dimensions are for every part.

It isn't about whether the 6905 bearings support the bike's weight, it is about load on the bearing. And low speed rotation can be more damaging when loads are high--static load ratings are lower than dynamic load ratings. If the design didn't require the highest quality and if the mating parts didn't really matter, then we wouldn't see *some* driven flange bearing failures, would we? And to be fair, even a highest quality bearing can/will fail prematurely if loads are frequenly very high on it, if the bearing is undersized, and/or if there's an unintended final stackup of dimensions and fit of the bearing in a particular assembly.

'Fortunately' the failures are detectable at tire changes and tire changes are frequent. ;-) And fortunately it us unusual for both bearings to fail simultaneously.

Unfortunately, there's no unbiased third-party tester of bearings. There are poor standards of testing (tests setup differently by different vendors to tout their bearing as better), and there's no uniform application and statement of bearing 'quality'. So, vendor A's 6905 bearing is not as capable as vendor B's 6905 bearing, even though they both claim the same rating (if vendors A & B tested each other's bearings, they'd both claim the other vendor's bearing was inferior to theirs). And then vendor C doesn't even test their bearings, doesn't have process control at the *micron level* that bearings require. If the bearing turns when it is assembled, vendor C ships it! I'll take vendor A or B bearings over vendor C's any day.

Bearing life is driven by bearing quality, by the amount of interference fit, by load, and by many other factors. Cheap bearings do not have the same level of control on tolerances of each ball, the raceway on the innner ring, the raceway on the outer ring, the OD of the outer ring, the ID of the inner ring, and the shape of the cage around each ball. Also, parts mating to those bearings have to be designed well, have to anticpate the load directions, load magnitudes, and temperatures--otherwise bearing life is short. Either/both the bearing and the application need to be well matched.

In studying the ST's wheel, driven flange, rubber isolators, rear ring gear assembly, etc., it is easy to see that with high applied torque (both during the long duration of when maximum power [torque] is applied and reverse torque spikes during engine braking)--given the ST's final drive assembly design, the driven flange tries to twist off-axis of the axle. The only way this load is taken up is by the 6905 bearings on one end, and into the smalley snap ring and rubber isolators on the other end (of the driven flange). Fortunately, most of the time there's not ~100 ft-lb of torque through the ST driveline (or we'd likely see only 100's of miles between 6905 bearing failures).

Obviously, I'm not the Honda engineer who designed all the mating parts--and there are a LOT of mating parts and bearings around the ST's rear axle (6 bearings total!!), and the loads between them is complex. I don't have access to Honda's prints on all the parts to see the tolerancing on every single part, to perform a FEA to see the loads through the driven flange, and then to make final calculations which match those parts' dimensions and tolerances to the bearing's dimensions and tolerances. But certainly, the 6905 is the smallest bearing there, and clearly by our collective experiences that bearing in this application is proven to be marginal.

If you search ISO bearing and shaft fits, and look at some of the online calculators and literature, it is easy to see how complex and confusing this topic is ... and how easy it is to make a design mistake. If you read bearing literature and speak with bearing design companies, you quickly get into the complexities of bearing dimensions and tolerances, and see that there *is* a difference.

In my searching, I see that some 6905 bearing manufacturer's state a static load rating of around 7kN (about 1573 lb-force), and others list that as the dynamic load rating, illustrating how uncontrolled the industry is. BTW, that load rating is for a bearing that has been properly designed, fabricated, and tested, and is based on a perfect application (greasing, cooling, inner and outer race fit, load direction, etc). 7kN is a relatively low number and is tied to the bearing's overall small size. With the ST's ~100 ft-lb torque through the driveline, and with the small dimensions of the ST's rear axle assembly to counteract that torque, I expect that loads applied to the left-most 6905 bearing reach or exceed 1500 lbf. I.e., I suspect 7kN is undersized for the design (and hence why Honda used 2 of the bearings side by side trying to solve the problem without making the bearing larger and growing the whole rear drive assembly's size).

I further suspect Honda has an error in the mating collar's bearing seat dimensions/tolerances (or Honda hasn't checked their collar vendor!). I have a spare collar, and it has different dimensions at the bearing seat than the one that came in my bike (and which was in place at the first bearing failure at 35k miles). Two 6905's don't fit the same on that orignal collar's seat compared to the replacement collar I have installed now.

So, I believe that Honda made a mistake (still has a mistake) in individual part(s) and/or the assembled dimensions/stackups of the rear drive design. This is not such a big mistake that it is needing recall, rather a mistake that allows some bearings to survive, and others not. And putting a higher quality bearing in place compensates to some degree for design mistakes. And as mentioned earlier, cheap bearings do not have the same load rating as well-controlled name-brand more expensive bearings. While cheap bearings aren't *certain* to fail, they are *more likely* to fail in a demanding application (the ST's rear assembly).

To wit: we see *some* ST driven flange bearing failures, and *some* of BMW's final drives fail. There's a lot of loads/torques in either final drive, and individual bearings and assemblies can lead to failure. Even the best engineers make mistakes in design, even the best bearing manufacturers can make mistakes, but it is guaranteed that no-name bearing manufacturers don't even know the dimensional variation that they manufacture into their cheap bearings--those cheaper bearings will on average have shorter life.

This post is too long... sorry all. :eek::

So, *I* use the best quality bearings (name brand bearings or Honda OEM) to reduce chances of short bearing life. Why test fate by using a $2.50 bearing when the OEM bearing is $15? How much would really be saved?
 
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dduelin

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After all that the only thing we do know is the savings is $12.50 and no ST1300 has a FD problem of any consequence. :)
 
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ChucksKLRST

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Yea, What Baker Boy said. Having changed out a few drive flange bearing during my 12 years of ST1300 ownership, I can attest to the cheap vs quality bearing issue. My last bearing change, I replaced with a one piece CBR drive flange bearing. Then I solved the matter for good and traded the ST in for a ....another manufactures Sport Touring machine. No more drive flange bearing issues.;) To answer your question. I would replace the bearings with OEM or go after market with CBR bearing Co. He has and knows what bearings are required for the ST1300 and the ST1100. Stay away from the the 5 buck bearings @ the bearing stores. BTDT
 

MajorTom

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After all that the only thing we do know is the savings is $12.50 and no ST1300 has a FD problem of any consequence. :)
Well I got quite a bit more out of BakerBoy's post than that, including that I need some Finite Element Analysis (FEA) software if I really want to understand what the loads and pressures are in my STeed's final drive. :) But seriously, I really appreciate the explanation as to why cheap bearings aren't a good choice and, as someone who found the idler bearings to be nothing but bits and balls when I removed my back wheel for a tire change, I will never try and save a few bucks by buying cheap bearings.
 

Mellow

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I'm kinda in the middle...

my 03 ST1300 had a bearing failure (OEM Bearings) and I took it to a dealer who replaced with OEM Bearings... it failed within the next 5-6k miles... so I assumed it was an install issue. The next dealer replaced them and they were good til I sold that bike but I think that was just a few more miles down the road.

That made me paranoid when I got my 08 and I replaced those about every other tire change once I saw how relatively easy it was, I replaced with all balls bearings.

One thing to remember is we wouldn't be having this discussion at all if the OEM bearings lasted... they don't always do that, some do and some don't. It might be the design of the flange/final drive or it may be just a bad batch of bearings... kinda like early thermostat failures that we believed were due to the paint over spray of the radiator inlet getting into the coolant.

So, what does that mean.. well, John has some great points above and I agree that the OEM stuff 'should' be of higher quality but I'm just not sure it is.. They outsource a lot of stuff and make changes they won't tell us about because they probably don't want everyone with an older part coming in to get the newer part..

Bottom line, check ALL the bearings during a wheel change. I think I'm the only one that I remember on the site having a new bearing fail before the tire was done but again, I think that dealer messed up the install or maybe didn't even replace them but greased.. not sure but I would never use them again.

Here's an article on how to replace them if you haven't already seen it.
https://www.st-owners.com/forums/showthread.php?55014-ST1300-Rear-Flange-Bearing-Replacement
 

SupraSabre

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In my 295,000 miles, I have had three fail. My '05 failed once (with 174,300 miles) I'm thinking the '04#1 failed and one set on my 2010. I don't remember the miles, I'd have to look at my maintenance books.

Also, we found that my brothers '05 failed when we had to have Khris change out the tire back in 2013, on our way to Oregon!

At least it's easy to spot!
 
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Thank you all for the thoughtful and helpful guidance. At 50k miles and a new tire going on the back, we will see how a new set of OEMs perform. Have a great Christmas and holiday season!
 

FL-STrider

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I ordered new tires last month with plans to install them over the Christmas break. My bike has 25,265 miles so I'm averaging just over 12K per set. Last tire change I had the dealer do completely. This tire change I decided to tackle partially myself and my rear flange bearing were absolutely "TOAST" once I removed the wheels. I dropped the rims off at the dealer and asked him to replace them all since they were mounting the new tires. I'm sort of kicking myself now for not checking this forum first however I will just chalk it up to experience. Honestly I wouldn't have never expected a bearing on a HONDA to fail so soon especially since my bike is driven gently and garaged.

As I mentioned it was just the flange pair that failed, however I'm having them all replaced even the front pair since I planning a long trip this summer. So just for clarity it's typically the flange pair that fail is that correct? Obviously tire changes happen every 9-12k miles, so it sounds like they should inspected then.
 
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