- make enough repairs to your bike to get you home (or to a phone or place where you can find help),
- be prepared in case of emergency (to you or someone else), and
- follow the golden cycling rule of fix it yourself or have the supplies so someone else can do it for you with your supplies (mooching repair supplies is tolerated but always looked down upon).
You can cram a lot of stuff in a little saddle bag. The rest goes on your bike or on you.
- Card with ICE (In Case of Emergency) info: your identification (name, age, important medical info), names and telephone numbers (parent, spouse, sibling, friend, etc.), health insurance, and important medical info (alergies, conditions, etc.)
- Cash, including a $1 bill: money for emergency ($10-20 should be good), plus a $1 bill which is handy in the event of a big tire blow out
- Cell phone, phone card/code, or credit card number (so can call or use pay phone to contact someone)
- Inner tube (1 or 2)
- Tire levers
- Tube patches: in case you get multiple flats or damage a tire severely
- Tire pump or CO2 cartridge inflater (check cartridges and pump regularly to make sure they work)
- Simple repair tools (multi-tool or individual tools) including: spoke wrench—if you break a spoke this makes the ride home a lot easier; 4, 5, 6 mm hex wrenches; and chain tool to reassemble your chain if it breaks
- Saddle bag: just big enough to fit the items above
- Water bottle: the water's great, but it also doubles as a wound cleaner, hand washer, and storage compartment
- Helmet: don't leave home without one