Wanted to get some thoughts from the long distance experts... here's my ride summary, would you weigh in with why you think I cramped, and what I might do about it in future?
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www.hh100.org

Did the cat 4 100 mi RR.

The course is soooo flat, and this year the temps were mild and there was barely any wind at all.

So... a 30+mph start (did not feel good on my not-warmed-up legs)...
A steady stream of surges and attacks and the accordion effect of an 80 rider pack with one lane (centerline rule)...
Attacks at every rest stop (where well-meaning volunteers were handing up cups of water... right)
Attacks at each of the 2 sanctioned feed zones (thanks to whichever studly dude made me chase while shoving water bottles down the front of my jersey.
Attacks on every patch of road that was not level (not many)

Despite all that, we rolled back into Wichita Falls with at least 50 guys together.

So a 100 mile rr turned into a bell-lap crit at the end. Which ordinarily I would dig, except I was full-leg cramping from about mile 85 everytime they surged. I discovered I could stand and sprint and not cramp, so that's how I did the final 3 miles.

I had no team support, so I wore a hydration pack w/ 4 servings of Hammer Perpetuem, plus a bit of coffee for flavor. 2 large (plain water) bottles on the bike, a gel flask and banana for backup. No breakfast other than a big glass of water, 4 sportlegs pills, and a cuppa coffee.

There were 2 feed zones that promised "neutral water" handups and luckily enough they both had plenty of volunteers with pre-opened bottled water. So I grabbed 2 bottles at each one.

I only finished a bit more than half the hydration pack, about half the gel flask and a couple bites of banana, so I probably should have eaten more. Might have prevented the cramping, ya think?

I used up _all_ the water, but timed it well so that I was taking my last swigs as we rolled into town.

If it had been much hotter, the water would have been an issue since I like to pour a lot on me.
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So here are the thoughts I've collected re: the cramping:
- first twinges started in my inside thigh, the Sartorius http://www.laboratorium.dist.unige.it/~piero/Teaching/Gait/Netter/thigh_muscles_superficial_anterior.png
- I suspect that the shape of my Brooks B-17 has something to do with that, it rubs a bit while pedaling. But could it be position-related?
- by mile 90 or so, it was full-leg cramping, which to me indicates some combination of exhaustion / lack of nutrition/hydration.
- the odd thing is, my legs "felt ok" as in I didn't have the dead, nearly-bonked feeling I'd expect. I still had the gumption to jump out of the saddle, but the muscles werent' supporting me while seated.

Thanks for any input!

So, what average speed or time did you take to finish the 100 miles.

I didn't do the HHH110 this year but a couple of years ago when it was very hot, I ended up with problems from mile 80 onward that I attribute to an electrolyte imbalance.

I had been hydrating with just plain water for the three days in advance of the ride. While I used GU sport drink during the ride, I believe I had managed to dilute the electrolytes in my body before the ride and the intake during the ride wasn't sufficient to correct the problem. Next time as I hydrate before the ride I will take in electrolytes with the water on the days before the ride.

You might never pinpoint the exact reason you cramped up.

we finished in 4:11; after cooling off and riding back to the hotel my speed avg was 23.1

another guy said to me, "don't over think it, it's always one of the usual things - heat, fatigue, electrolytes, food, water"

I know that of course, and my suspicion is that I didn't take in enough Perpetuem. But always looking for 2nd opinions.

The lack of any meaningful nutrition before the ride and the minimal amount of electrolyte replacement would suggest electrolyte imbalance to me. Sounds like you took in some carbs, but not much sodium or potassium.

Even if you were examined directly after the event by professional medical staff the nature or cause(s) of your cramping would remain speculation.

As with 99% of any and all cramping that results from exercise (exercise-induced peripheral muscle convulsions) - current research remains inconclusive and contradictory. However, acting as "Doctor" Richard Cranium I hereby declare that you cramped because your muscles were tired and your fluid and mineral balances failed to remain homeostatic.

Please send $79.95 to my paypal account.

Your Welcome.

"current research remains inconclusive and contradictory"

That's what I read years ago, and I haven't seen anything to negate it. People normally associate it with lack of electrolytes, but two different people can drink the same things and one will cramp and one won't.

I had cramping problems too. And I was chugging pickle juice and power ade at every rest stop I came to. It wasn't my whole leg. But anyway, I don't know that there's a way to prevent it in any given circumstance.

hope you don't mind me asking some questions here also?

What is the proper hidration prep for before...meaning straight 16oz of water for 3 days before kind of thing.
Also pickle juice...I am assuming for the sodium?

The Pickle Juice website is here:
http://www.goldenpicklejuice.com/
More electrolytes than other drinks it, says, whether sodium or whatever. I don't know that this is the same stuff actually found in a pickle jar, for that matter, I assume not.

Perpetuem has almost no electrolytes in it. That could easily be contributory.