Race well all
Check spokes and rim tape on the inside of the wheel, to see if it's something from the inner side that is the cause.
Foggy, the only thing I would recommend based on my experience is eccentric stretches of the Achilles which has helped me a fair amount with my calf problems.......not completely cured but has helped.
Would love to be with you all, just make sure you all race well and then drink well afterwards / on Monday
Visit the official Runner's World page
Follow Runner's World on Twitter
Other Natmag-Rodale Sites
Run For Charity
About Runner's World