Even if you have the best friendship in the world with the mechanics down at the local bike shop, you should be prepared to do the most basic repairs yourself. To do that you will need a good basic toolkit. What should go into this toolkit though?
The first thing you should put in is a full Allen key wrench. You will need one with a ton of different sizes and all in one easily accessible central place so you can quickly test through them to find the right size for the job. The reason for this is that just about everything on a new bike or even a bike from the past ten or 15 years is adjusted by Allen wrenches.
The next thing you will absolutely need is to have the tools to easily change a tire. This is the single most common bike repair procedure you will be doing and you will want to have everything on hand so that when it happens you can quickly and easily repair it. The tools you will need are a patch kit, a spare inner tube for when its really bad, and the tools to remove the tire from the wheel. If you are really good you will also have backup rim tape you can use.
Next up is to have all the cleaning and lubrication things you will need to keep the bike running smoothly. Grit and grime work their way into a bike with ease all the time so it is important to clean and maintain your bike regularly. The easiest way to do this is to keep a chain cleaning kit, degreaser and some form of chain lubricant. Using these regularly (some people do it every ride, some people every couple) on a set schedule is very very important. Also for the best effect with the chain lubricant make sure to use the same type every time.
Source by Jeff Hendrix