Wheel Bearing Question

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Wheel bearings seem to be a high maintenance item on bikes - by that I mean they get replaced fairly often compared to auto roller type wheel bearings.

Why do mc's have ball style bearings which do not last as long as car bearings? Are the engineers trying to keep unsprung weight low? is it because of the design of the axle? Or am I mistaken and on the average, they last as long as car bearings (and I've just been fabulously lucky w/ my cars)?
 

Byron

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It probably boils down to a couple of things, I believe ball bearings offer less rolling resistance. Ball bearings are lighter than tapered/roller bearings. Ball bearings are less expensive and bikes don't normally put on the miles that cars and trucks do. They also do not have as much force put on the bearings so can get by with ball bearings.
 
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It probably boils down to a couple of things, I believe ball bearings offer less rolling resistance. Ball bearings are lighter than tapered/roller bearings. Ball bearings are less expensive and bikes don't normally put on the miles that cars and trucks do. They also do not have as much force put on the bearings so can get by with ball bearings.
But, unless I'm wrong, they don't perform - by that I mean last as long as car bearings. Or are we - ST riders atypical LD riders putting way more miles on bikes than average?
 

dduelin

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I think I had one front wheel bearing require replacement at just under 100,000 miles. Without looking at records the others are OEM at 172,000 miles.

Flange bearings aren't wheel bearings and they are subject to torsional loads not seen in automotive applications. Are these what you are thinking of?
 
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I think I had one front wheel bearing require replacement at just under 100,000 miles. Without looking at records the others are OEM at 172,000 miles.

Flange bearings aren't wheel bearings and they are subject to torsional loads not seen in automotive applications. Are these what you are thinking of?
Nope. It just seems like there is a lot of talk about checking and replacing wheel bearings. Of course, I don't really know how many actually get replaced, and checking is not unusual.

What do you mean by torsional loads on the flange bearings?
 
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Newer vehicles have the whole cartridge assembly for the front wheel bearings. Both fronts on my Chevy Silverado and a Jeep Cherokee I owned had to be replaced at @ 50k. I believe these assemblies now have ball bearings instead of roller bearings?
 

T_C

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Tapered bearings have to be loaded (compressed in a sense) to function properly. Ball bearings in our application have a wider range of acceptable values for side force.

Yes, tapered bearings would be better but they would be hard to properly set with a shaft driven bike. Roller bearings would be good too... but probably last too long
 

dduelin

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Nope. It just seems like there is a lot of talk about checking and replacing wheel bearings. Of course, I don't really know how many actually get replaced, and checking is not unusual.

What do you mean by torsional loads on the flange bearings?
Flange bearings only support the driven spline which applies driving force against the wheel through rubber biscuits that allow a twisting or torsional load.
 
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Historically, most bikes are pushed to the back of the garage or out behind it long before major components are worn out. Keeping a bike running for high miles is a fairly recent thing among a relatively few of us bikers.
 

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Nope. It just seems like there is a lot of talk about checking and replacing wheel bearings. Of course, I don't really know how many actually get replaced, and checking is not unusual.
Flange bearings ARE the ones that are talked about most HERE and fail mostly due to the stresses Dave mentioned.. it's just the design and not all of them fail, many members will never even need to replace them.
 

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In the 300K+ miles I've done on my 5 bikes;
Replaced (Miles I put on it/miles total)
'05: front wheel bearings X1, flange bearings X1 (maybe 2?) - (174.3K miles/174.3K miles)
'10: None - (65K miles/66.5K miles)
'12: None - (14K miles/14K miles)
'04#1: Flange bearings - (37K miles/68K miles)
'04#2: None - (26K miles/41K miles(?))

I really don't see where the bearings are that big of a deal. I remember replacing plenty of front bearings on my previous cages a lot more!
 

jfheath

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As I understand it, the rate of wear of a bearing is proportional to the cube of the load that is put on it. So double the load, the bearing's life is reduced by a factor of 8. So different people will have different results for how long is needed between bearing replacements.

Motorcycle bearings need to be able to withstand lateral loads as well as vertical, which I would guess is why roller bearings are not used.

Bearings that are not installed correctly in the ST1300 can have lateral loads imposed right from the outset. I've seen the effect of this after watching a dealer install front bearings. I didn't realise he was doing it incorrectly at the time - I know better now - Those bearings lasted 10,000 miles only.

OEM bearings seem to be better for longevity than aftermarket bearings - in my experience. (Depends on what you find, I suppose). I once contacted a bearing manufacturer for a suggested replacement. They said they couldn't possibly recommend a bearing unless they knew a whole load of stuff about loads in all sorts of directions, duty cycle, temperatures, rotational speeds .......and a whole load of other stuff that I have forgotten about.
After seeing that, I always make sure that I have a full set of Honda wheel bearings available before my next tyre change (so far I haven't used them !) - they have already done the work on what is suitable.

Currently I am on 30K miles on original bearings. We ride fully loaded a lot of the time. I checked them all a couple of weeks ago when I had new tyres fitted, including the flange bearings - not a sign of any roughness or play.
 

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Wheel bearings seem to be a high maintenance item on bikes - by that I mean they get replaced fairly often compared to auto roller type wheel bearings.
...
Wheel bearings really aren't a high maintenance item on bikes. Of all the bikes and auto wheel bearings I've owned, I've replaced more auto wheel bearings than motorcycle wheel bearings: two vs zero, respectively. And the two auto bearings I replaced were decades ago and were tapered roller bearings (which are much more capable than radial ball bearings). Also, ball bearings in my dirt bikes have taken tremendous abuse, and they all were durable as I never replaced any of them.

True, the driven flange bearings on a Honda ST1300 are failure prone (flange bearings are not wheel bearings). As others have pointed out, the flange bearings are loaded quite differently than are wheel bearings, and I think Honda didn't get that design right and knew it (hence why there's two 6905's adjacent to each other trying to 'survive' the torsion loads, even worse the loads are reversed between acceleration and deceleration!). But that's a different topic.

...
Why do mc's have ball style bearings which do not last as long as car bearings? Are the engineers trying to keep unsprung weight low? is it because of the design of the axle? Or am I mistaken and on the average, they last as long as car bearings (and I've just been fabulously lucky w/ my cars)?
There is a key 'axle' design difference: an auto bearing/axle has to endure twisting loads from cornering the car, without the wheel being able to lean to keep the axle perpendicular to the load. But given MC's lean, MC bearings are generally always loaded radially (except in torsional situations like the ST's driven flange bearing or in some single-sided swingarms). Therefore, the car axle is designed differently (more complex and weighty) so that tapered roller bearings can be used to handle those extra loads that motorcycles generally don't have. So motorcycles are simpler overall and ball bearings are quite sufficient.
 

dduelin

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Wheel bearings really aren't a high maintenance item on bikes. Of all the bikes and auto wheel bearings I've owned, I've replaced more auto wheel bearings than motorcycle wheel bearings: two vs zero, respectively. And the two auto bearings I replaced were decades ago and were tapered roller bearings (which are much more capable than radial ball bearings). Also, ball bearings in my dirt bikes have taken tremendous abuse, and they all were durable as I never replaced any of them.

True, the driven flange bearings on a Honda ST1300 are failure prone (flange bearings are not wheel bearings). As others have pointed out, the flange bearings are loaded quite differently than are wheel bearings, and I think Honda didn't get that design right and knew it (hence why there's two 6905's adjacent to each other trying to 'survive' the torsion loads, even worse the loads are reversed between acceleration and deceleration!). But that's a different topic.


There is a key 'axle' design difference: an auto bearing/axle has to endure twisting loads from cornering the car, without the wheel being able to lean to keep the axle perpendicular to the load. But given MC's lean, MC bearings are generally always loaded radially (except in torsional situations like the ST's driven flange bearing or in some single-sided swingarms). Therefore, the car axle is designed differently (more complex and weighty) so that tapered roller bearings can be used to handle those extra loads that motorcycles generally don't have. So motorcycles are simpler overall and ball bearings are quite sufficient.
I'd agree with most everything you posted except the design reference. I feel that Honda got a bad batch of bearings in early STs but after initial replacement the R6905s last a good long time. My first set were replaced at 96,000 miles and the second set is still good 76,000 miles later. After the discovery at 96,000 of a bad inner one at each tire change I pull the flange out of the hub and check each 6905 out of the flange.
 

BakerBoy

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Probably a number of factors Dave. A bad 'batch' would have been HUGE as they used this 6905 bearing in many Honda motorcycles 2000 and on. I suspect perhaps more likely to possibly be involved could be a lesser capable bearing manufacturer that they had a contract with for a number of years, concurrent with a poorly managed collar machining tolerancing.

I ordered a spare collar after my first flange bearing failure so that I could have a spare set of bearings on a collar already assembled, making tire changes quicker when/if I found bearings failed (my bike or others that come through my garage).

What surprised me was how different the Honda bearings fit the new collar as compared to the original collar that came in the bike. So during a tire change, I pulled the original collar and removed the bearings to measure various parts. My measurements showed the OD at the bearing seats to be about 0.001" different from each other on the two collars, and further collar OD's were different from where one bearing would seat vs. the other bearing on that same collar. I found the various Honda and aftermarket 6905 bearings I had on hand to have very repeatable ID.

So I put new Honda packaged bearings on the new collar and installed it in the ST given that the original collar allowed the bearings to fail in about 30kmi (I forget exact mileage). That setup (new collar, Honda bearings) didn't fail and was still with the bike when I sold it.

I didn't take the issue any farther than convincing myself that one Honda collar wasn't machined as appropriately as the other. One would need to see Honda's collar prints, specifications, and measuring a bunch of collars as produced to know what the issue really was.

But for designing proper bearing seats, 0.001" difference of two 'identical' parts is simply a glaring issue that does not lead to good, consistent bearing life. As a result one pair of 6905 bearings on a collar can last a long time, while another set of bearings on the very same collar will last less time just because the collar isn't optimum dimensions and slight bearing differences will become more prominent.

For perspective, on a recent high speed shaft-bearing/housing design I managed, I did the bearing calcs (they're more detailed than most realize). Following SKF's design criteria, I specified the bearing seats to x.xxxx" +0.0004" -0.0008". And that was for various bearings having 42mm bore and larger.

So my finding a 0.001" seat difference on a 25mm seat from the two collars I had in hand shows that Honda messed up [at least for one of the two collars I had in my hand].

Related... I see that the driven flange inner bearing collar is also used in the rear drive assembly of the 2003+ VTX 1800 and VTX 1300 (as are the pair of 6905 bearings) ... I suspect those bikes also showed some premature driven flange bearing failures too for exactly the same reasons. Anyone know if that is true?
 

dduelin

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A retirement-aged Honda tech I know told me one time that VTXs had numerous flange bearing failures. Maybe you are right. Still, even with toasted bearings the design does not catch fire or sieze up and the rider has little to no clue one or both bearings is bad.
 

jfheath

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Just for additional info:

I once wanted a bearing more quickly than I could get a Honda OEM part delivered. I went to a motorcycle dealer and he was able to provide the required 6905 ( I think they were) bearings. He knew they were for the front wheel of a motocycle. I got them home, and they felt slack. Quite a bit of 'play' in them. Maybe my fingers are oversensitive to detecting wheel play having spent years adjusting the cone bearings on push bike wheels, but they didn't feel right to me.

I checked the number on the box - 6905, yes, that is right - but I wonder what that C3 is for ?

It turns out that the same number bearing can come in a variety of formats, and the suffix C1, C2, C3, C4, C5 indicate the variation in clearance from the standard bearing. C1 and C2 indicate less clearance then the norm. C3 indicates marginally more clearance than normal, and C4, C5 represent even more clearance than normal. If there is no suffix, then the bearing has the normal spec clearance.

Not an issue if the correct Honda OEM bearings are used, but certainly an issue if aftermarket bearings are used, and the installer wasn't as curious about the suffixed code as I was.

There was nothing stamped on the shell to indicate that this was a C3 bearing. Just the 6905 bearing number. The only indication was printed on the box. At least one bearing manufacturer's website that i have seen says that motorcyles do not need the extra clearance offered by C3 bearings.

Maybe some of the reported early failures have come from workshops or owners installing the incorrectly rated bearing. The 6905 code simply relates to the bearing size and type.
 
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Byron

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But, unless I'm wrong, they don't perform - by that I mean last as long as car bearings. Or are we - ST riders atypical LD riders putting way more miles on bikes than average?
As other have attested, they do perform but like other parts some last longer than others. My bike still has all the original bearings with over 100K miles on it. It may have to do with the way you ride or the conditions during the rides. Or, how things are cared for. I've never had a shop work on my bike because I'm not a very trusting person when it comes to someone else caring for my vehicles. Good mechanics are rare as hen's teeth. :)
 
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Just for additional info: I checked the number on the box - 6905, yes, that is right - but I wonder what that C3 is for ?
Once when I was buying bearings from Bearings, Inc. (one of those multinational humongous corporations that happens to be headquartered here in Cleveland) I started asking the counter guy why the bearings I was buying from him were so expensive compared to what Makita (or Rockwell, or whoever) wanted for the same part for their tool. He told me that aside from ordering 12 zillion of them (what the Mfr of the tool would do) and the fact that I was buying one, there were differences in quality due to the manufacturer of the bearings. He said they generally quoted prices for Tier 1 companies - SKF, Timken, etc. and the tool manufacturers were making their tools to fit a price point - and would often use Tier 3 companies for their bearings. Now, I have no idea if there is in fact a breakdown of Tier 1, Tier 2, and Tier 3 bearing manufacturers or if this was slang within Bearings, Inc., but it all made sense to me. At that time, he listed a bunch of well known and lesser known companies and the tiers they belonged in. I've since forgotten the nuances, but remember the gist of what he said.
 
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