It's what they did stock.
I think the same blank may have been used for 1" as well as 1/2" and the
shoulder was there as reinforcement and rigidity.
If you look at the older steel rings you will see similar construction.
style.
It was carried over for "X" years until modern metallurgy and design enabled
otherwise.
Ted Ernst
Palos Verdes Estates
CA USA
> Thank you Mark, Galen and Ted. I've officially been schooled on this one.
>
> So were all 151 bcd Campy Pista rings extra enforced? Or is it more of a
> half-half thing?
>
> Thanks
> Mark Buswell
> SF, CA USA
>
>
>
> On May 14, 2007, at 8:47 PM, Mark Bulgier wrote:
>
>>
>> Mark Buswell wrote:
>>> I don't know what the BCD is of this particular ebay crankset.
>>
>> galen pewtherer wrote:
>>
>>>> I don't know that the one pictured is 151 BCD, [snip]
>>
>> http://tinyurl.com/
>>
>> Here's the trick to spotting 151 cranks/rings at a glance: Notice the
>> space between the chainring bolt heads and the crank spider. On a 144
>> crank that space is almost nothing - about a millimeter - vs. 5mm on a
>> 151. The crank pictured is 151.
>>
>> Mark Bulgier
>> Seattle WA USA