I came home this afternoon from a hard (rocky) ride and had a flat just as I was pulling into town. When I got it home and pulled the rear to change both tire and tube - I found I'm also missing a spoke. The rim looks straight so I'm not too worried.

What size spoke does the rear take?

 

Funny, i had a really loose one and couldnt adjust the nipple on my bike so i ordered a new spoke and nipple from http://www.ronayers.com/