Rear Sprocket Spins, Wheel Stays Put

[duibhceK]

Wow, how is that even possible.

Hard to tell from the pic, but it looks like the sprocket carrier bearing failed (not unusual on these bikes and their BMW cousins, been reported on here before). Excessive play on the bearing causes cracks to start forming on the flange where the bearings are seated in around the areas you see in the pic. I saw the exact same damage, although at an earlier stage, on my wife's Terra.

Mike will be extremely lucky if there aren't also cracks in the wheel hub.

 

[TR650 Mike]

The wheel appears to be fine. Does anyone know if this will work as a replacement?

http://www.ebay.ca/itm/01-12-BMW-F-...ash=item35f485ac54:g:4sAAAOSw5ZBWMlrm&vxp=mtr

 

[mag00]

It looks like it is the same as what the G650GS uses and that should fit our Terra's. Check the casting numbers on your hub against those in the listing. 2 345 803 36.31

 

[glitch_oz]

Check the casting numbers on your hub against those in the listing. 2 345 803 36.31

Seconded!!
The numbers are sort of opposite the "TOMOS" logo on the carrier.
If the numbers in the cast match those of your bike (different manufacturer but same numbers in the cast) then all is good.

 

[engineerk9]

I just can't imagine driving with the racket it must have been making.

When I changed my rear bearings, I was dumbfounded by the lousy design.

On most axle setups, the spacers ride on the inner race of the bearing. On our drive hub, it has some dufas overlapping spacer, and if you over tighten the rear axle, you will stress the bearings.

That is why I had to replace mine, over tightened rear axle.

Technically impossible to over stress the bearings by over tightening the axle nut

 

[engineerk9]

Survey Says...View attachment 61863
I'm going to need a new sprocket carrier.

This looks like a match, what do you guys think?
http://www.ebay.ca/itm/01-12-BMW-F-...ash=item35f485ac54:g:4sAAAOSw5ZBWMlrm&vxp=mtr

"interesting" possibly loose axle nut allowing the hub to "flog-out"

 

[mag00]

After my 600m service is when my bearings went. Chain too tight, axle too tight and bolts in sprocket cover crossed.

The manual says: Tightening of rear wheel axle nut (1): 100 Nm - 10 kgm - 73.75 ft/lb



edit: after my 600m dealer service.

 

[drzcharlie]

"interesting" possibly loose axle nut allowing the hub to "flog-out"

Dave,

I don't disagree with the actual torque values and I do use that same torque when I am messing with the rear axle, but those values were set by engineers that know the strength of the materials used. You you can (probably, I have no facts to back it) deduce that that value was over engineered by the designers for liability reasons.

I sort of have to agree with Engineer. I mean that's the reason the spacers are there right? I think if you over tighten you might risk stripping the threads on the axle or nut and maybe a remote possibility of stretching the axle itself but that would be an enormous force to cause that.

 

[Mark_H]

Survey Says...View attachment 61863
I'm going to need a new sprocket carrier.

This looks like a match, what do you guys think?
http://www.ebay.ca/itm/01-12-BMW-F-...ash=item35f485ac54:g:4sAAAOSw5ZBWMlrm&vxp=mtr

Arggh is this yet another design fault on the Lemon Bike or did the OP inadvertently cause serious damage in one way or another - I wonder ??

 

[engineerk9]

Arggh is this yet another design fault on the Lemon Bike or did the OP inadvertently cause serious damage in one way or another - I wonder ??

No design fault - I stripped my unit down completely, renewed the bearings with better quality, packed with good quality water resistant grease, used stainless steel replacement spacers (replacing questionable aluminium) then tightened up the nut to what I considered perfect (engineer tight)

I do wonder about the Operator/maintainer - I'm a Marine Engineer by profession, I've a good idea of which end of a spanner to use - certainly the failure of the cush drive needs a bit more investigation, rather than forum "guestimates"

 

[WayneC]

That is the first time I have seen/heard of a failure in the rear hub cush drive and there are around 200,000 machines using it, bearing failures yes due lack of sealing. The rubbers have been degrading and getting loose after around 30,000 kms but many 650GS owners have not been replacing them and not suffering failures. There have been at least 2 minor variations in casting over the years but all are interchangeable so any 650GS hub will fit

 

[mag00]

Arggh is this yet another design fault on the Lemon Bike or did the OP inadvertently cause serious damage in one way or another - I wonder ??

Yes, another design fault, carries over to the BMW's as well.

Dave,

I don't disagree with the actual torque values and I do use that same torque when I am messing with the rear axle, but those values were set by engineers that know the strength of the materials used. You you can (probably, I have no facts to back it) deduce that that value was over engineered by the designers for liability reasons.

I sort of have to agree with Engineer. I mean that's the reason the spacers are there right? I think if you over tighten you might risk stripping the threads on the axle or nut and maybe a remote possibility of stretching the axle itself but that would be an enormous force to cause that.

You will need to take your rear wheel off and line all the spacers and bearings up, examine how they function and come to your own conclusions. I have, and I stand by mine. Pay particular attention to the way the bearings and spacer are in the drive side. If you can, please take pictures while you are in there, and share with us the results.

It's been about 2 years since I have had mine apart, so the specifics elude me. It was "experts" at the Husky Dealership that screwed mine up. They over torqued the axle nut, and over tightened the chain amongst other mistakes. Don't put all your faith in "experts", we've been there with the air box. Some are still there with stumbling.

... certainly the failure of the cush drive needs a bit more investigation, rather than forum "guestimates"

It has been investigated, and the findings are conclusive.

1. Poor quality bearings
2. Poor design of spacers
3. Over tightening of axle and chain that stresses poor design and parts.

 

[MotocycleWriter]

It has been investigated, and the findings are conclusive.

1. Poor quality bearings
2. Poor design of spacers
3. Over tightening of axle and chain that stresses poor design and parts.

So, replace the bearings (or inspect them regularly)
Replace spacers with steel.
Inspect rubber from time to time.
Always tighten to correct torque (100 Newton-meters, says the manual, or 73 ft-lb)

 

[glitch_oz]

So, replace the bearings (or inspect them regularly) yes
Replace spacers with steel. if it makes YOU feel better....I'll happily use the alum spacer (the outer "spacer" is steel anyway...the C-clip!!)

Inspect rubber from time to time. regularly
Always tighten to correct torque (100 Newton-meters, says the manual, or 73 ft-lb)
again, if it makes YOU feel better, I've never used a torque wrench.... and never had an issue. I do it up tight and to a point where I can use the onboard tools in the bush to peel the wheel out...I don't care about the book or anyone else.

 

[mag00]

The problem spacers are the ones in the drive hub. It has been a couple years since I had mine apart, and forget exactly the details on why it sucks so bad. I just keep remembering some sort of overlapping spacer, that really didn't have a function other than not running the inner race on the axle shaft. Can somebody post up some good photos to refresh me?

None of the repair or parts manuals sufficiently picture the setup.

 

[PaulC]

If you owned a torque wrench YOU would use it

 

[glitch_oz]

If you owned a torque wrench YOU would use it

There's 3 in the tool box....somewhere.

The problem spacers are the ones in the drive hub. It has been a couple years since I had mine apart, and forget exactly the details on why it sucks so bad. I just keep remembering some sort of overlapping spacer, that really didn't have a function other than not running the inner race on the axle shaft. Can somebody post up some good photos to refresh me?

None of the repair or parts manuals sufficiently picture the setup.

There's only a single (alloy) spacer tube through the center of the hub.
It's a straight bearing knockout on one side, the other side has a C-clip over the bearing/ under the seal. Having replaced bearings on a Strada as well as a Terra hub, I couldn't find anything unusual (compared with other bikes I've worked on in the past). The spacer tube is not load-bearing nor rotating.

 

[mag00]

There's 3 in the tool box....somewhere.




There's only a single (alloy) spacer tube through the center of the hub.
It's a straight bearing knockout on one side, the other side has a C-clip over the bearing/ under the seal. Having replaced bearings on a Strada as well as a Terra hub, I couldn't find anything unusual (compared with other bikes I've worked on in the past). The spacer tube is not load-bearing nor rotating.

How many bearings in the rear wheel assembly? How are each of those bearings held in proximity?

It is a bit deceiving , it takes a close examination/study to see how it really is arranged and works.

 

[engineerk9]

There's 3 in the tool box....somewhere.




There's only a single (alloy) spacer tube through the center of the hub.
It's a straight bearing knockout on one side, the other side has a C-clip over the bearing/ under the seal. Having replaced bearings on a Strada as well as a Terra hub, I couldn't find anything unusual (compared with other bikes I've worked on in the past). The spacer tube is not load-bearing nor rotating.

The spacer tube is under compression load from the tension in the axle

 

[engineerk9]

There's 3 in the tool box....somewhere.




There's only a single (alloy) spacer tube through the center of the hub.
It's a straight bearing knockout on one side, the other side has a C-clip over the bearing/ under the seal. Having replaced bearings on a Strada as well as a Terra hub, I couldn't find anything unusual (compared with other bikes I've worked on in the past). The spacer tube is not load-bearing nor rotating.

What about the spacer in the cush-drive hub?