I bought a medium at first and it was definitely too small. The large overlaps just a little, but it is much better than the medium.
i bought the large and HATE it. I just took everything out of it and put it all losely in my bag. It is too big, too tall, pockets are too deep. Hope you like it better than I!
I have a medium and it's too loose in a Speedy 30. Try the large.
Large is best for a speedy 30.
Check out this thread...