|The PAX Index
was a system of handicapping cars, so that drivers in different SCCA classes
could compare times against each other. John Kelly tells us it was invented by Jim McKamey for a series of
autocrosses he ran at one time, and has been updated each year by Dave Beck.
The RTP index is a separate set of indexes, calculated from
different events, but basically similar. They used to be
separate, in any case, but as of 2002 Dave Beck no longer maintains
the PAX index, and Rick Ruth has combined them into the
index. Info about it is maintained at
"This Index was developed by Rick Ruth and reflects
results from over 30 large events including, the Tire
RackŪ Solo II National
Tour, Subaru CenDiv,
Region SCCA, Tri-State
Sports Car Council and Wisconsin
Autocrossers Inc events. This index is designed to
incorporate some of the previous PAX substance with the RTP
Index of the past"
This index is the basis for the SFR Handicap
The RTP/PAX index for the fastest class (AM) is always 1.0. For any
other class, multiply your time by the index for your class to get the time
you theoretically would have run in an AM car.
2004 SFR Handicap IndexSan Francisco Region uses the straight
RTP/PAX index, with the addition of entries for OSP and
are not national classes and therefore do not have RTP/PAX indexes). We index
OSP at .856 for people running in Novice
and Street Tire classes, for example.
||CS ||.811 |
|STS Street Tire||.810
||STX Street Tire||.830
Street Touring indexes
For 2004 all Street Touring classes must run "real street tires"
while Stock and Street Prepared classes may run competition tires
(e.g. Hoosier Autocrosser) which are a lot stickier and provide a
significant performance improvement, perhaps 1-2 seconds per
minute. The RTP/PAX index takes this difference into
account for indexed overall order of finish. However, in
classes that require the Stock and Street Prepared
classes must run street tires (e.g. Novice, Street
Tire) these indexes give Street Touring cars a
As of 2004 March 16, Street Touring (STS, ST2, STX, STU) cars are
excluded from the Street Tire class.