If the contents are all soft you can try to make it as flat as possible and then use straps to wrap it wound the top tube, a la:
I've got a full frame bag so that's not an option. With the bar bag properly stuffed it actually seems better anyway. I might see what I can do with some shock cord, but hopefully it shouldn't be a massive issue.
@Jon. started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
If the contents are all soft you can try to make it as flat as possible and then use straps to wrap it wound the top tube, a la: