Ken- Your take on bearing load capacity is the opposite that I understand. I've always heard (and see in my work) that the load a bearing is a geometric factor of it's diameter. So half the balls of twice the diameter will result in the unit having twice the load. If the ball count remained the same (and the overall size of the unit then grew) the unit would have 4 times the load capacity.
My take on the smaller balls in the Pista unit was two fold. First the smooth track conditions didn't require maximum load capacity and the overall stack height could be lower. this allowed a lower bar/stem position.
Any one out there have more definitive information?
> For the same race diameter, smaller balls allow more balls in that
> circumference. Half the ball diameter would allow twice as many balls.
> More balls allow more points of contact and better load sharing, i.e. the
> contact pressure at each contact point is less than for a larger ball.
>
> No, bigger is not always better!
>
>
>
> On Sun, Jan 10, 2010 at 8:46 AM, Dean Nixon
> <vintage.lugged@gmail.com>wrote:
>
>> In particular for the Super Record models - they seem identical even in
>> the
>> old catalogs. Other than the bearing size (3/16 vs. 5/32) is there any
>> way
>> to tell the difference visually? Measuring the diameter of the races
>> would
>> be difficult I think. Also, will the races get damaged if they are used
>> with
>> bearings that are either to large or too small? What is the rational
>> behind
>> using 3/16" bearings for the pista version anyway? Just wondering...
>>
>> Dean Nixon
>> Toronto, Canada
>> _______________________________________________
>>
>
>
>
> --
> Ken Freeman
> Ann Arbor, MI USA
> _______________________________________________
Andrew R Stewart
Rochester, NY