Originally Posted by NJRoadBiker
You may have nailed the cause here. I find that I only cramp when I've ridden significantly beyond either the distance or degree of intensity of my conditioning.
You probably just need to train more above the distances and level of intensity that you'll be doing group rides.
This makes sense, but it happened at about mile 30, and I do 30-40 mile rides without any discomfort all the time.
I'm leaning toward insufficient electrolytes. I've ordered some pills to try on my next long one, and I'll be sure to drink more water.
Thanks for all the responses.
Jim