Originally Posted by OnyxTiger
Have you checked your bike fit? You may possibly be putting undue strain on your calves if the bottom of the pedal stroke is just a bit too low. If not, I'd probably play with lowering the saddle ~5-10mm and see what that does.
^^^^^This is accurate info. My seat was about 1 cm too high and even though I had a bend in my knee at the 6 o clock position, I was being forced to push my toes down on the down stroke and didn't even know it. I was not cramping but on long rides with lots of elevation I could feel something wasn't right in my feet and ankles.
On another note, several years ago my right hamstring started cramping and it was a nuisance for many years. Even while kneeling at church sometimes the thing would start to cramp. I started stretching and I occasionally eat pickles, pickles, pickles lol. Pickle juice does wonders for cramps.