Timbuk2 Under-Seat Bicycle Pack
The Timbuk2 under-seat pack is a simple design that I like a lot. It can be used to carry just about anything. It is available in a variety of colors to match your bike.
The Timbuk2 pack size large weighs 107g. For my road bike, I take a scissors to it, and cut out all interior padding and the keychain hoo, which also provides just a bit more stuffable interior room, and drops the weight to 86g as a trivial bonus.
On my road bike, I use it to carry a spare tubular tire and tire sealant.
On my mountain bike, I use the Timbuk2 pack to carry a spare tube, CO2 cartridge, Lezyne pump, tire levers and a few small tools. A size large is best for a full kit, but a medium can be used for a basic kit.
Warning: on the mountain bike, I have found that the Timbuk2 can unzip itself on very rough descents. This has happened to me twice, scattering the contents all over the trail, a real disaster if one is far out, where loss of a tool or CO2 or etc could mean a long walk home.
Therefore, I can no longer recommend this pack without care taken to secure the rear hatch with another strap. Nice pack, very poor zipper design, though I’ve never had a problem on my road bike.
I am looking for a similar capacity pack without this critical problem— perhaps JAND.
See pricing at Amazon @AMAZON.