Whether its your phone and keys or everything you need for a 100 mile ride cyclist always face the dilemma of just how to best carry their personals on a bike ride. For some that means shirts with funny back pockets or back packs, others use bags that attach to the bicycle in various out of the way locations. In the world of cycling not all carrying solutions are created equally. Luckily I am going to try lay down the basics I have learned over the past 20,000 miles as to what goes best where.
The most common bag sold at bicycle retailers is the saddle bag. A fist sized bag that secures itself to the under belly of your seat. All of my bicycles have one of these and I generally keep the things I would not leave home with out:
Spare Inner tube, multitool, patch kit, inflation device and some spare currency for emergency.
This bag never leaves the bicycle and I try to keep a separate one stocked for each of my 2 wheeled whips.
Now what if you want to ride a little longer and you want to carry a phone, wallet, some snacks and maybe even a camera? well a bicycle jersey is a form fitting garment that has 2-3 pockets across the lumbar area. The fact that these supplies are on your lower back makes them less likely than a pants pocket to chafe, and it also secures them in one of the least mobile parts of your body (close to your center of gravity)
For the all day excursion where you might want spare H2O, a lunch, some spare clothing such as a rain coat or arm/leg warmers this is where a back pack shines! Most bicycle shops worth their salt will carry a variety of hydration packs, these are back packs that have a pouch that can be filled with liquid that has a long straw that reaches all the way to your mouth so you can hydrate on the go. Hydration packs also have pockets to hold other supplies as well. They will also usually have secondary straps that secure the pack to you much better than the two standard chest straps most packs have.
These are the most common bags that cyclist use but stop by your local bike shop and see the plethora of options that exist because there is surely one to fit your needs.