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#1021362 - 10/22/18 02:15 AM Re: Final drive service - spline lube? [Re: poodad]  
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Pappy35 Offline
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Near Memphis, TN
This is true but another factor is the compressive stress on the clamped components. Since the final drive casing is aluminum and the bolt is presumably steel, one could very well crush the underlying materiel. The low torque limit, and the need for secondary retention (torque and then loctite or locking nut), suggests to me that clamping down the bolt to such a high value might have other unpleasant consequences. It's been a long time since I've calculated bolted-joint loads (I've worked gas-turbine engine stress analysis for many years) but this could be a contributing factor to that low max torque spec.


'13 R1200RT 90th Anniversary Edition
#1021377 - 10/22/18 12:35 PM Re: Final drive service - spline lube? [Re: Pappy35]  
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dirtrider Offline
The Oracle
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Originally Posted by Pappy35
This is true but another factor is the compressive stress on the clamped components. Since the final drive casing is aluminum and the bolt is presumably steel, one could very well crush the underlying materiel. The low torque limit, and the need for secondary retention (torque and then loctite or locking nut), suggests to me that clamping down the bolt to such a high value might have other unpleasant consequences. It's been a long time since I've calculated bolted-joint loads (I've worked gas-turbine engine stress analysis for many years) but this could be a contributing factor to that low max torque spec.


Morning Pappy35

While it is true that the final drive casting is an alloy (mostly aluminum) the paralever reaction link doesn't bolt directly to the aluminum casting ear. The final drive reaction ear contains a rubber bushing with a steel-center-sleeve molded into it so the paralever reaction link actually bolts to that thick walled steel sleeve in the center of the bushing.

Even so, the BMW service manual specs the bolt torque on that 10mm/10.9/ x 55mm long bolt/nut at 42mn & as mentioned above that is way below the max bolt/nut generic torque specifications for a 10mm/10.9 bolt/nut.

Obviously that 10mm bolt is used in shear not tension so it doesn't need a high torque to on the nut to do it's job.


D.R. ___
Sent from my rotory dial wall phone!
#1021442 - 10/23/18 04:24 AM Re: Final drive service - spline lube? [Re: poodad]  
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Pappy35 Offline
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Ah. Yeah. Good stuff. I love learning (or relearning) stuff. Nerds never grow too old to geek out on engineering chatter.


'13 R1200RT 90th Anniversary Edition
#1021456 - 10/23/18 04:50 PM Re: Final drive service - spline lube? [Re: Pappy35]  
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poodad Offline
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Originally Posted by Pappy35
Ah. Yeah. Good stuff. I love learning (or relearning) stuff. Nerds never grow too old to geek out on engineering chatter.


Except that I'm even more confused about what I need to procure in order to lube the splines on the final drive!

#1021486 - 10/24/18 03:19 AM Re: Final drive service - spline lube? [Re: poodad]  
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Pappy35 Offline
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Pappy35  Offline
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Near Memphis, TN
Get a new lock nut and torque as specified.


'13 R1200RT 90th Anniversary Edition
#1021497 - 10/24/18 12:13 PM Re: Final drive service - spline lube? [Re: poodad]  
Joined: Jun 2010
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dirtrider Offline
The Oracle
dirtrider  Offline
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Ohio
Originally Posted by poodad
Originally Posted by Pappy35
Ah. Yeah. Good stuff. I love learning (or relearning) stuff. Nerds never grow too old to geek out on engineering chatter.


Except that I'm even more confused about what I need to procure in order to lube the splines on the final drive!


Morning poodad

On your 2011 1200 camhead--

Most (that I have worked on anyhow) 1200 camhead bikes require as new bolt as they use a micro encapsulated bolt. My official camhead BMW dealer service manual also calls for a new bolt but not a new nut.

To be sure (on YOUR bike) you will have to determine (IF) your bike now uses a microencapsulated bolt or a standard bolt with locking (torque prevailing) nut. Then replace the bolt if it is microencapsulated or replace the nut if it is a locking (torque prevailing) nut.

OR, if still in doubt then just order a new bolt & a new nut then replace both. (this way you cover ALL bases). (new nut is only about $1.10 from BMW)

Or, another option is to re-use your original bolt & nut using Lock-Tite on the cleaned threads (personally I use red Lock-Tite).

The original bolt & nut are not stressed anywhere near their working limits so are basically re-usable many times (as far as stretching & work-load limits go), the reason for required replacement is ONLY due to the nut retention safety aspect.

[Linked Image]




D.R. ___
Sent from my rotory dial wall phone!
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