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Any of you guys ever spent any time playing with Harley Sportsters? One of the major things that separate a Sporty from a Big Twin and a very easy way to instantly tell one from the other is by looking at which side of the rear wheel the bike is being driven by.. Sporty on the right, Big Twin on the left (ok,, there are some aftermarket tranny companies that also produce right side drive for a big twin but we wont go there)..
The Sporty right side belt drive to the rear wheel is not that far off in basic design when compared to the SS and I thought,, for discussion sake,, maybe we could apply some lessons learned therein to the SS...
One of the things anyone who has ever built a Sporty up to over a 100 horse,, put a little more tire on it to help it hook up and than played with it on a drag strip, will tell you is that the drive pulley on the tranny (found on the right side of the bevel gear on the SS) has to have additional bearing support or the internal bearings within the tranny have a very short life span!!
If you look at the front pulley on an SS and than look at the front pulley on a Sportster you will notice that neither of them have an outer bearing supporting the right side external portion of the pulley.. What happens is as torque is supplied to the pulley, the shaft it is riding on suffers undo stress because it is only supported on one side.. After many transmission bearing problems with 600 pound, 100 horse, belt drive Sporties,,, someone came up with the brilliant idea of adding another support bearing to the outside of the pulley on the Sporty - IT WORKED!!! All the grinding, howling and destructive behavior of an unsupported pulley putting undo stress on the end of an output shaft was instantly cured!!!
It will be interesting to see how the stock SS bevel gear noises change over time,, its possible that break-in will eleviate most if not all of the noises BUT,, its also possible that 1700 pounds at 170 horse is speaking the words "please add some support to that drive pulley" that us ol Sporty folks are familiar with.. If nothing else,, as we see the SS evolve into extremism with motor mod's, turbo charging and wider rear tires to give us that AWESOME hooking up feeling we love,,, my moneys on the added bearing support for that pulley is something we are gonna see - DO I HEAR AN AFTERMARKET BUSINESS OPPORTUNITY KNOCKING?
 

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Not too crazy about the cantilevered shaft either but if diameter and material is right, no reason it can't be reliable. I don't know the numbers on the SS so don't have an opinion on that yet.
 

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I agree with Otter; bearings are all about adequate load rating.

Also I'm not sure I get how an undersized bearing results in pulley/belt noise, unless maybe the supporting structure is deflecting so much that tooth engagement geometry is affected.
 
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