To upgrade to Cat 1 all you need to do is complete a few Cat 2 races. There is no set race finsh qualification.
From the rulebook:
1D6. Mountain Bike Upgrades
(a) Riders may advance as quickly as they wish up to
category 2. However, once a rider has upgraded, he or she
will not be permitted to downgrade to a less difficult category
without making a formal request to USA Cycling. The
upgrading of categories will be noted on the racing license by
USA Cycling. The USA Cycling Official at the event may record
the upgrade of a rider to Category 2. The official will then
contact the USA Cycling Regional Coordinator to record the
change. A rider may also contact USA Cycling by email, in
writing, or online to change categories.
(b) Category 3 racers
must move to Category 2 after
placing in the top five in five races. Failure to do so may
result in license suspension.
(c) Category 2 riders
may move up to Category 1 after two
top five finishes by presenting an upgrade request and a
resume to USA Cycling.
(d) Category 2 riders
must advance to Category 1 after
placing in the top five in five races. Failure to do so may
result in license suspension.
For mandatory upgrading purposes, classes must consist of
the following competitors:
Senior-15
Master age 30-39- 15
Master age 40-49- 10
Master age 50+- 5
In those classes that require a minimum of ten competitors,
the top three in the class are counted for upgrading. In those
classes that require five, the top finisher will be counted for
upgrading. Upgrades will be based on a rider's placings in his
category over a calendar year.
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Bottom line- as a Cat 2 you need two top-5 finishes to upgrade to Cat 1. I'm pretty sure Norm has reached that threshold, though...