Getting your bicycle tuned up at a bike repair shop in advance of a trip is a good way to limit the risk of running into a problem when you're on the road. Although this service appointment is valuable, you should also take the time to put together a small toolkit of items that you can rely upon in the event of a problem with your bike. Just as you might carrying a first-aid kit for unexpected problems along the way, a handful of repair tools can be vital in getting you back on the road — even if you have to make a detour to the closest bicycle repair shop for more of a permanent solution. Here are some essential tools to carry.
An Allen wrench is a handy item to keep in your bike repair kit because it has multiple applications. Depending on the design of your bicycle, you may be able to use this simple tool for adjusting the brakes, handlebars, or another part of the bike. Take a look at your bike before you travel and select only the sizes of Allen wrenches that you'll need. These wrenches typically come on a ring that contains many individual sizes, but there's no point in carrying those that aren't the right size for your bike.
Tire Patch Kit
You aren't likely to carry an actual spare tire on your bicycle trip, but as long as you're carrying a tire patch kit, you can fix most tire-related issues on the side of the road. This kit is small and lightweight, consisting of one or more rubber patches and a bonding agent. If you suffer a flat tire, you can remove the inner tube from the tire, identify the source of the leak, and patch it in short order. Although you may wish to buy a new inner tube when you're able, the patch kit will allow you to continue to ride.
An adjustable wrench might seem like a simple tool, but it's valuable because you can use it for several adjustments on your bike. In many cases, the things that aren't adjusted with an Allen wrench are designed to be adjusted with an adjustable wrench. If you're concerned about the space that a full-sized wrench occupies, you can look for a stubby version. It will still get the job done, but without adding bulk and weight to your backpack, which may be an issue if you wish to travel lightly.
Just remember it's best to leave serious problems to the professionals!