2011-07-16/17 Sat/Sun - Dunwich Dynamo DD19

I've used/own a large and a medium version of that ortlieb saddle bag, they work good. Personally, for a single ride I wouldn't take more than the medium sized one but I like to pack light - if you want to pack lunchboxes, spares, and clothes and other miscellaneous crap a la fakenger style then the large one is your best bet. The waterproofing has worked well in my limited experience of using it in the wet - depends if you do it up properly.

I've never had any problems with it swinging though, since there is also the little velcro clasp which secures it to the seatpost, in addition to the plastic bracket which attaches to the saddle rails.

If you don't have a brooks, you needn't worry about extra straps. If you do I can't help you....but you can probably buy them online somewhere...or improvise. In a nutshell:

Cheers mate that helped out no end. I don't have a brooks so no trouble there! I was going to buy this to hold food and spares my current saddle bag is a specialized wedge and I can't quite get everything in there and thought if I'm buying new I might as well buy three biggest one as that will benefit me more in the long run.