How do you carry your flat kit?

[MartianDestiny]

Camelbak, but then I always wear one on the MTB. If I didn't I'd move the seat bag over from the roadie.

[Irulan]

Ditto on the seat bag for tube & levers. Jandt used to make a really nice small one that is perfect for this. DH has a nice frame pump, I keep one in my pack.

For MTB, you want a nice little one that won't get in the way of your body english when riding.

[sundial]

I have a small seatbag for 1 tube, tire changer, and patch kit for when I ride with tubes. When I'm tubeless, I carry just the inflator and an old tire to be used as a boot. I keep a spare tube handy even though I'm riding tubeless. Note to self: Duck tape would probably be a good idea to carry too.

[spokewench]

I carry a multi tool, a couple of co2 cartridges, a tube, and some tire levers either in my pocket of my jersey; or more usually in my camelback since I don't use water bottles when I mountain bike. They get too dirty and are too hard to drink from when I am bouncing around on a bunch of rocky trails.

You can use a small saddle pack; but I don't ever put the tubes in those because sooner or later the tube will get rubbed by the zipper and be damaged.

[lph]

I have a tiny seatbag (PI) that holds one tube in a ziplock bag, (folded around and rubberbanded to protect the tube), a co2 pump, a cartridge and a couple of tire levers, and that practically disappears under my saddle. I can squeeze in 2 tubes and 2 cartidges in a pinch but then it bulges a little more.