Taking a bike out on the road or out on a trail means you put your bike in harm's way. There are many things that can go wrong when you are out on the trail, and if you are not prepared, then your bike can end up riding on your shoulder instead of you enjoying a nice ride in the country. While you may not be able to prepare for everything that could go wrong, the right set of tools can help you to deal with most problems.
One of the most common problems that you could have out on the trail is a flat tire. Whether you decide to patch the tire with a flat kit or carry a spare tube so that you can get on your way quickly and patch the damaged tube at your leisure, you will need a bike pump to inflate the tire to get on your way. Look for a model that is easy to use, inflates your tire quickly, and will be easily transportable.
There are many multi-tools on the market. Some of these tools are designed for generic usefulness, and you will find on them a set of tools that could be useful in a variety of different situations. If you buy such a tool, you will get something that may have some usefulness on a bike ride but will otherwise be extra weight. Look for a multi-tool designed by a company that makes biking tools. Furthermore, make sure that any tool you are interested in has pieces that are designed for the bolts and components that you have on your bike. This will allow you to make adjustments to detailers, brakes, or other malfunctioning equipment while you are out on the trail.
The final piece of equipment that you will need is a spoke wrench. As you are bumping along down the trail and riding through brush or what not, your spokes can get knocked out of true. If you know what you are doing, you can use your spoke wrench to adjust your wheels and make sure they are working properly.
If you are looking to buy a few tools to take out on the road, you should be able to find what you need at a bike shop. Just make sure that you know the brand of componentry you have on your bike so you can buy the best tools for your bike. Check out a company like Tri-A-Bike Inc to get started.