Not sure if RR="Race Ready". I suspect that a single R means "Race", and they just double it to emphasize extra "raciness"...err, hmmm, like they do with some cars, some have "S" (for sports model), or "SS" (even sportier) or even "SSS" (now were getting gay) tagged onto their model number etc.
I think that the "ZX" designation is applied according to the following:
"Z" = Road.
"K" = Off-road.
"X" = Competition.
Out of that you get ZX-6/10/7/2, whatever, and KX250/125/60/80/500, whatever.
You can argue that bikes like the ZX-11 and ZX-6E (ZZR-1100 and ZZR-600 respectively) aren't competition bikes, but they were when they were new.
Suzuki have a similar thing for their models. GSXR isn't just a name, it's an actual model designation according to what the bike is.
I think "G" indicates 4-stroke, "S" = twin camshafts, "X" = 4-valve head, and "R" is something I can't remember, but probably has something to do with road or race-replica.
GPZ = grand prix street
KZ = street
Z = sport street
ZX = faired sport
KX = off road sport
# = CC designation / class for street and off road use
R = competition
ZZR = Supersport
RR = race homologated (the RR was introduced on the street when the 6R got 636 cc's, the RR had a 599cc engine for race rules homologation...the ZX-RR is for faired sport race homologated, and the lack of a CC # means it's race-only)
The letters themselves, I think, are arbitrary. They had to pick something, and it had to be something no one else picked...so why not.
BTW, SS is Super Sport in the car world, too, not just in Ducati Land. =)
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