Phelps Morris:
Thanks for that post---it's very informative and in line with what we've been finding with a similar process and "reasonable maximum" green speed study at my course--Gulph Mills G.C. (Ross-1916) in Pa.
I've been to and played Crystal Downs a number of times over the years and have been aware that a number of people (I think including Tom Doak) felt the club was running speeds too high for the types of greens the course has.
Some of the greens of Crystal may have a bit more slope on them than we have, but perhaps not. It sounds to me like the membership greenspeed survey as to what's ideal or the "reasonsble maximum" green speed (9.5-10.5) for that course is right on the money and completely in line compared to what we're finding!
However, there seems to be a couple of interesting factors involved with playability when putting greens reach the 11 area on stimp reading. That is at right around that reading and green speed the putting surface loses the necessary friction to bring the ball to rest and the phenomenon of "ball creep" enters the equation of playablility where the ball on any kind of slope or contour simply loses its ability to come to rest and continues to move obviously taken by the effects of gravity. One thing all should come to realize with putting speeds with this phenomenon at work is none of us are going to alter or reinvent physics!
A good example of "ball creep" due to lack of necessary friction on the putting green to bring a slowly moving ball to rest which some might remember was the putt of Phil Mickelson's on Saturday on the 7th green of the US Open at Shinnecock. He had about a 10 ft putt for par breaking right to left from slightly above the cup. The ball missed and the camera followed it very closely as it ever so slightly continued to roll very slowly (ball creep) until it appeared to almost rock and catch perhaps on a single blade of grass app. 20 ft below the cup. If that single blade of grass had not caught the ball it would've continued to build up speed on the higher slope below it and roll into the bunker to the left of the green.
Speeds that high (obviously over 11) with the inherent lack of friction on the putting surface incapable of holding even an extremely slowly rolling ball is really playing with fire in the area of playability.
In my opinion, a stimpmeter reading in the range of 11 may be the magic greenspeed number that no greens anywhere in the world ever need to exceed again! It'd be my hope that the USGA Green Section may step in soon and make this declaration officially to golf courses, supers and green and golf committees everywhere!
It's looking to me like the universal maximum speed limit on greenspeed may've now been identified and determined and that it's apparently right around 11! Anything over that stimpmeter number will get into the freakish problem of lack of necessary friction on putting surfaces with any amount of slope and contour to allow a rolling ball to come to rest! Clearly this is a problem with playability that putting greens never had before in the history of golf until relatively recently!
I have no problem with putting greens that're interesting and very challenging requiring large amounts of imagination and concentration that may even require taking some lines of putt heretofore unthought of but it appears even slightly above 11 on the stimp with greens with any kind of slope or contour even for the best players in the world speeds have entered the area for everyone of just "no can do!" And when that starts to happen the only thing anyone can expect is simply non-stop "train wrecks" on the putting greens.