My cramping experience is that I have cramped a few times on long/difficult rides (four of them that I can recall). 2 of them were under conditions where dehydration/etc is totally ruled out (temps under 50). These cramps were all in the inner thigh area and the 'solution' is to completely straighten the cramping leg (which can be extremely difficult sometimes). If it is both legs and you are going uphill (where standing up without pedaling is impossible) you have like 2 seconds to unclip and get off. Flats or downhill just stand up for 30 seconds.

I have had identical cramps just sitting around the house, in the middle of the night, etc. I would guess that has happened maybe 50-100 times in the past 5 years. They are exactly the same as the ones that have showed up during long/difficult rides. I recall one in particular that was on a third consecutive rest day (and I recall that because 3 consecutive rest days are most unusual for me). It showed up while I was watching TV.

My sense is that these 'not exercise related cramps' are triggered by specific positions of the leg. I just feels that way. It is like there is some very specific angle of my leg that if you hit and hold it for a few seconds (like within 0.1 degrees or something), here comes the cramp. It just feels like that. I never get non-exercise cramps when I am anything other than totally still.

Just my personal experience.

dave

ps. I routinely do 100 minute rides in weather as hot as NC can throw at me and more often than not just don't bother drinking from my luke warm water bottles. I have never cramped as a result of that and I am a heavy sweating type (up to 4 pounds per hour). But 100 minutes is roughly the max that I would consider going without drinking.