The Arundel Tubi seat bag is large enough to securely hold a well folded tubular tire but we imagine a lot of sales to clincher user who like to carry more than just the minimum tools. Its always good to have one of those guys in your group ride to bail out most riders like us that only carry the bare minimum.
This bag is certainly a welcome addition for tubular users. Just tightly fold a tubular for a nice secure fit in the Tubi for a small tidy bag that does not flop. A CO2 cartridge can be placed in the first fold of the tire or in the separate zippered side pouch. The Tubi is designed with a thin profile so it won't rub your bike shorts. The strap is double sewn so it can be cinched tightly and not flap.