A multi-tool is great for on-the-road repairs and adjustments but try to have a good set of Allen keys in your toolbox.A decent T-handle set with a ball end on the long side is a good place to start (this allows you access to awkward bolts with reduced risk of rounding).
Torque wrenches are available cheaply and you can get very compact bike-specific ones — the bonus to using them is that you avoid over-tightening anything, which can affect your warranty on parts you regularly tighten like the frame, fork or handlebar.
Just remember to undo the torque adjuster before throwing it back in the box.
Always apply anti-seize compound to the pedal thread before installation. A good pedal spanner is usually flatter and thinner than a regular spanner, which you may struggle to get between the pedal and crank arm to undo.
A chain tool will come in handyOli Woodman / Immediate Media
How to know when it’s time to replace your bicycle chain
A chain tool is an essential bit of kit you should get familiar with using properly.
Use it to avoid stiff links and to enable you to take your chain off for serious cleaning and so prolong the life of your chain and parts. You can even use it to take out a link and put a speed-link in to make removal/cleaning even easier.
Investing in a chain-wear check tool can also help you keep on top of maintenance and save money in the long run.