dan kasha wrote:
> In setting up a proper BB for my track bike, I am trying to
> understand the campy NR thick vs thin BB cups.
>
> 1) Is there a way to visually tell what I have, or to measure
> something with a caliper?
The think cups are thick (~3mm) and have rifling inside the hole.
> 2) What is the reason for the thin vs the thick, is it to be able to
> get the crank closer in? Are both the fixed cup and the adjustable
> cup thinner?
Both cups are thicker to accommodate the rifling, which in turn is done
as a means of expelling debris that collects on the spindle. You need
the proper spindle to work with these cups, as the races are closer
together than on an ordinary spindle.
> 3) Finally, why did other models use them, I think the tripples
> (again, is it for more clearance so the crank can be in closer?), and
> the GS cranks used them.
Nuovo Record and Super Record used the thick, rifled cups. Everthing else used the thin cups. The short-lived off-topic "off road" group from the early 90s also used thick cups, but a neoprene seal (like the on-topic Tange sealed cups) instead of rifling to keep contamination out of the BB.
--
-John Thompson (john@os2.dhs.org)
Appleton WI USA