Every endurance event teaches me something.
At the half marathon, I kept a faster pace than I was used to over the distance, and the new intensity drained my energy. I bonked, was very close to the wall.
Lesson: fuel up, keep the gels and energy drinks going!
During Paris to Ancaster, I had major cramping, to the point that my quad was absolutely locked and wouldn't release. I've had this once before, when I came back and did a 65K ride after being injured for 2 months and not training... so I already pretty much know the answer to this one!
Causes of Cramps (source: here and roadbiker.com)
The most common cause is under-training. I haven't had much time on the bike this spring, it was colder later and it was tough to get out, plus I was battling a knee injury. So the 3-4 times I got out just weren't enough. This was probably the reason for my case.
This might have played a role. I didn't bring that much water - two big water bottles, and one little one that I almost finished before the race even started. I managed to grab a bottled water along the way, too, but only about half of it made it into my mouth.
I read a few theories here, but most point to salt, potassium, calcium, or magnesium. Sports drinks cover salt and potassium, but I might just carry Rolaids next time for calcium and magnesium.
Endurolytes sounds like a way to go - everything in a pill.
So I'll start carrying some of this stuff as back-up, but I'm pretty confident the issue was just a training thing. I've done harder rides without problems, but not usually so early in the season.