Last Sat I and 5 others did a 115 mi loop around Lake Okeechobee. I drank 5 qts of "gatorade", and had 3 endurolytes at each of 3 stops: 38, 63, and 93 mi. When we took off from the last stop they picked up the pace a bit to 22 - 23. At almost 100 mi is started to cramp in my left leg. I dropped the speed down to 18 and raised my cadence and kept my heels down. I spun it out for a few miles and we got it back up to 20 no problems.

We had to do a "cyclocross" over part of a golf course to get back on the levee for the finish. I was careful to not work too hard in the grass or on the ascent up the levee. I was able to get it back up to 22 by mile 105. When they pushed it back up to 28+ in the final 2 mi, this old man dropped out at 26 as my HR was up to 90% and I could "feel" a cramp coming on.

So indeed, properly handled a cramp does not mean the end of the ride. Just slow down and spin faster at the first signs of a cramp.