Rear wheel hub rubber dampers

ChriSTian_64

ChriSTian_64

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Joined
Feb 5, 2020
Messages
810
Age
61
Location
Deux-Montagnes, Quebec, Canada
Bike
2000 ST1100Y
While replacing the 3 O-Rings of my rear wheel, I decided, just for fun, and because I'm curious, to inspect the state of the five rubber dampers of the hub. The maintenance manual don't say much about them, just how to remove and replace them. Not much about when and why to replace them, no schedule nor tolerance measurements.

So, I used 2 small prybars, and gently lifted the driven flange....
20210417_170009.jpg

Geee. That looks a bit dirty. A bit of old grease, rubber powder... A good clean couldn't hurt.
So, let's unscrew the five bolts of the dampers holder (6 mm alenkey).
20210417_170559.jpg

I could then "unscrew" (1/8 of a turn, counterclockwise) the damper holder, and have access to the five rubber dampers to "inspect" them.

I started to remove them, one by one, proceed to clean the hub (plenty of rubber and alu powder), and then...

What ! What's that ? What happend ?
Do you see that missing chunk of aluminum ?

20210424_141113.jpg

I certainly wasn't expecting that amount of wear... or.. it's more a damage than a normal wear, I think, since my 2000 ST1100 only has 22 000 miles / 34 000 km.
3 of the dampers are perfect, 2 of them had their aluminum insert that went thru the rubber damper and were scatching the bottom, wich is the hub.
20210426_150317.jpg

20210426_151702.jpg

Now, I took my micrometer, measured the diameter of the holes to check if they were ovalized. Nope... or so little... 0.4855 vs 0.4825... 3 mils of an inch.

Now, I'm not an engineer, but, unless I'm missing something, the five posts of the driven flange are moving clockwise or conterclockwise, so, they are squizing those dampers left or right. Not up and down.

So, what in the world could have pushed down two of those aluminum inserts enough to scrape the hub like that ?
And why just those two, and not the three others ?
See, just comparing a damaged damper (left) with one that is normal (right).
20210426_150732.jpg

My guess, is that it is probably while re-assembling the wheel, when the driving flage was put back in the hub, maybe it wasn't exactly straight and... by using a small hammer, two of the post pushed those inserts thru the bottom of the rubber dampers.
Or, more likely, a common problem while putting the wheel back in place, is that it don't fit right where it should go at the first try, and we have to play back and forth, turning the wheel a bit, until it slip in the right place.
But by doing so, we make the flange play back and forth into those inserts, and we may push them at the bottom of the dampers.
So, we have to be carefull in doing so.

A new set of five dampers and inserts, from partzilla, is about 250 canadian dollars.

Since my dampers and inserts are still good, not too slack, not ovalized, and all I need is find a way to keep the inserts where they should be, I think I found a temporary cheap solution, with water hose rubber washer.
20210426_150443.jpg

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Final remarks :

1- the total amount of damping has to be equally distributed among the five posts of the driving flange.
That is why we have to replace those dampers as a whole set of five, so that they all show the same resistive force to each posts. With one or two dampers scratching the hub like this, those posts were taking more than their share of the load.

2- Nothing was visible without disassembling the dampers. I think it shows the importance of visualy inspecting and cleaning the parts, whenever we have a chance to do it.
 
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ChriSTian_64 said:
Can't tell you. I have a memory leak.
Click to expand...

Did you find a thrust washer between the hub boss on the wheel and the spider? There should be one there. Either metal, or plastic was used also.

Your wear on the aluminum inserts is an indication that the spider is twisting under load and forcing the inserts towards the wheel. This sort of wear is typical of worn dampers.

Did the dampers come out really easily and just drop in place when you replaced them? If so, they are done. Your rubber washer is not the answer, otherwise Honda would have designed the assembly differently. New rubber dampers will require pounding into place with a rubber mallet. That's how tight they are intended to be.
You must replace all the aluminum inserts also. If the thrust washer has been missing as well, that could exacerbate the wear you see.

Many of us like to put a light smear of Moly on the spider pins too, before reinstalling it on the wheel.
 
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It don't look too bad Christian but I would replace the damaged aluminium parts whilst in there. It'll only play on your mind whilst riding.
Forget the hose pipe, no need.
I think the thrust washer Bush refers to is on the hub in the picture.
Replace the damaged ali, check the thrust washer, bit of moly, and ride. If it ever warms up.
Upt'North.
 
Just as Bush says, above, the dampers are toast and have to be replaced. Your washer idea addresses the symptom, which is the aluminum insert wearing through the damper and rubbing against the wheel, but not the root cause, which is a worn out damper and insert.

Partsfish has them for U.S. $158. Last time I purchased a set from them, about 5 or 6 years ago they were $113.

2002 Honda ST1100 A REAR WHEEL (1) | PartsFish.com

Shop online for OEM REAR WHEEL (1) parts that fit your 2002 Honda ST1100 A, search all our OEM Parts or call at 800-964-1882
www.partsfish.com www.partsfish.com

This place has them for U.S. $123.

 
I've had some of the same wear in the hub. My approach has been to cut some gasket material I found at the hardware store to the same shape as the dampers and to insert it between damper and hub. Nice tight fit.

Those darn pieces are way overpriced.
 
Meh, that is pretty light wear. If the rubber is still a tight fit, like takes pressure to reinstall, I'd run them. Look at the design, the dampers are only loaded on acceleration/deceleration, and only in the direction of rotation each way. The spider/drive flange rides on a bearing on the wheel, not the rubber dampers. The most likely scenario is someone got a little too enthusiastic on assembly, there was a burr that grabbed the aluminum insert and pushed it out of line. In operation, there is no force in that direction. A little moly on the pins is a good idea as is a close inspection of the pins and holes in the inserts. The rubber hose gaskets likely won't stay put, nor would they need to be that shape. A thin, like 0.060, rectangle of UHMW plastic or delrin would be a much better choice IF it was needed at all.

I'm not suggesting using worn out parts, if they are worn and loose, then replace them. However if they are still tight, something else went wrong. I approach any repair from the point of view that "parts are no longer available". How would you fix something if you couldn't get the part? What happens when Honda stops making this part? If you think like this, even with the new part in your hand, it will give you a better understanding of what the part does and the best way to install it. I get paid to think about things like this so I apologize if I got off track.

RT
 
Rubber powder, grease, = replace rubbers, o rings and thrust washer. Make sure the "o" ring grove on the wheel hub isn't burred. Before installing on bike push the flange over the wheel hub and make sure it doesn't push the hub o ring out of place.
 
rwthomas1 said:
The spider/drive flange rides on a bearing on the wheel, not the rubber dampers.
Click to expand...

I disagree with this statement. The bearing in the wheel is the inner wheel bearing for the axle shaft. The spider only contacts the wheel hub on the thrust washer surface. The clearance between the spider and the wheel hub's surface is quite small, but there is some clearance, hence the o-ring to keep the Moly in the thrust washer area.

When the dampers and inserts are worn, it will allow the spider to twist from 90 degrees to the axle, causing the spider to push those rubbers and inserts against the wheel that they face, creating the wear marks on that inner wheel surface. Christian did not show us a pic of that surface, but the marks will be there.

The lateral stability of the spider is quite reliant on those dampers being snug in their pockets and the aluminum inserts not being worn into an oval shape.

In extreme cases of wear in the dampers, where they will literally just fall out of the pockets, it causes that twisting to start destroying the aluminum boss on the hub itself, as the spider twists even more. We have seen numerous pictures of that type of damage here.
 
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There is a bearing plainly visible in pic #2 on the wheel that fits into the drive flange. Its not a wheel bearing, it supports the drive flange. Additionally, the splines of that flange engage in the drive. Any misalignment would allow rapid spline wear so engineering wise it would make little sense to support a critical item with rubber parts that are subject to wear. I haven't taken mine apart in a year, but that is how I remember it, and the pics bear this out. I can understand how in severe cases when the rubber is completely worn the force would be asymmetric and cause a twist. But the parts in the pics don't look anywhere near that worn. And as I said before, if they don't fit tight, then replace them.

RT
 
pic 2 is a wheel bearing, there is a thrust washer that sits on the hub, the hub supports the flange. The flange is like a drive shaft between the wheel and the diff. When the dampers are loose the flange moves back and forth on the hub excessively. Christians dampers are worn look at pic 6 rubber is cracked around the insert.
 
Alright I stand corrected, its been a year since I had mine apart and I'm not remembering it correctly. There is a vid showing the bearings being replaced and I thought what I was seeing is a bearing to support the flange. My mistake. It also didn't help that the parts lists two smaller bearings and larger one on the diagram I was looking at. Looks like you're buying rubber bits Christian!

RT
 
Not cheap. Adept Powersports in SoCal has them listed for about $135 US. I replaced them on my '96, but not sure what I'll do yet on the '97. I haven't opened it up yet.
 
Bush said:
Christian did not show us a pic of that surface, but the marks will be there.
Click to expand...

Looks like I have to correct myself too, in that pic #4 does show the wear damage from the inserts inside the wheel. Missed that pic on first perusal.
 
Thanks everyone for your inputs.
It is very appreciated. As a relatively new owner, it's always good to know what more experience owners think about it.

@Bush, yes, the thrust bearing was there, between the driven flange (spider) and the hub. I have one made of a kind of plastic.
I was expecting it to be thincker than that. It was still covered with a thin coat of moly.
Here, after I cleaned it a bit.
20210427_130753.jpg

@UpNorth, I think you are right Ray.
Not too bad for now. But it looks like the beginning of the end for those dampers. Yeah... I need to replace them.
Oh well... I will have to drink water for a while.

@ReSTored, thanks for the clue for partsfish and the other link. @Smudgemo also.
@Larry Fine will probably be glad, too. Yeah, there might be some cheaper places than Partzilla.

@DeanR, A sheet of gasket material cut to fit ? ah-ha ! A better idea than my hose gasket. So, all stays put in place. It can make a temporary fix. Yeah... the price they ask for those dampers....

@rwthomas1, agree with you. If it's time to replace, well, let's replace them.
But what schocked me, was to have this wear at 22 000 miles. That's about half their life time (John O mentionned in another thread, that, in his case, their average life is around 44 000 miles, but your mileage may vary, depending on many factors). Still, it almost make me wonders if it's the original wheel, or original mileage. But, who knows, previous owner might had used it in muddy roads at the chalet, heavy load with passenger, lots of hills, a more aggressive throttle handling...

@Bush, what I couldn't figure out, was what force could cause the inserts to move up and down along those posts. The real damping effect is a lateral movement, not up and down. But I think you gave me an insight... there might be some gyroscopic force at play here... when you try to steer a rotating wheel, it tilts it on its side. The same effect could push those insert up or down along the posts, when we tilt the bike in curves.

@Al st1100, yes, there was plenty of rubber powder, mixed with aluminum powder and kind of dried moly paste. Probably had never been cleaned in 21 years.

OK, I'll have a closer look at pic number 6.

As @ReSTored mentioned it, on those 5 driven flange (spider) posts, the manual ask that we don't put any grease, and that we keep them very clean. It even mention to wipe out any grease present. A bit odd, I admit. My understanding of this, is that rubber powder has a tendency to stick to the grease, and then, your posts gets covered by a thin black coat of gummy stuff.

Finally, yes, I am now convinced that my rubber dampers need to be replaced. Proof is that I can put them back in the hub with no efforts. I can almost drop them in place. They just need a very gentle push to fall in place. Deapite the low mileage... maybe their age (21 years old) had make the rubber less resistive.

Again, thanks you guys. ; -)
 
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