Apart from your mind, hands, and probably a bottle opener, there is no tool that you would use more than a hex key (or Allen key/ hex wrench). Despite this, it is quite saddening that most people prefer to spend more money on other bike tools, or worse – they make do with a multitool.
To make sure you get the best out of your bike, you need to get the right kind of allen key set. But, most professionals don’t agree on which is the best. Well, I would leave that choice to you. But first, you need to know the different types out there.
This tool is the most popular of the different types of hex tools. If you would have just one hex key set, it should be this. The L-shape is quite versatile and gives you access to tight spots. One drawback of this type is that it doesn’t have the weight you would need to easily spin the wrench making it uncomfortable to hold for long periods of time.
The T-shape of this type serves as a balanced weight to make it easier for you to spin the tool. It is the most popular for motorsport use. However, this tool would not be ideal for some parts of the bike, like the seatposts, cranks, and pedals. This is because those positions would be tight for the T-shape.
The P-handle is a type of hex wrench made popular by manufacturers like Park Tool and Pedros. If you frequent professional workshops, you are sure to see it lying around. It is essentially an oversized L-shaped wrench. The comfortable grip it has on its bend also gives it the same benefits you would get with a T-handle.
This type also became popular due to its creation and promotion by Park Tool. In this design, Park Tool places three of the most common sizes into a single device.
A lot of brands already have different sizes for the the three way Allen key. Regardless, the standard 4, 5, and 6 mm size still remains the popular choice. As an attestation to its versatility, you can easily build most parts of a bike with this single device.
Unfortunately, its triangular shape and limited length means that you can’t use this device in tight spaces. Trying to install bottle cages, adjust saddles or disc brake calipers would be quite difficult or practically impossible.
This type isn’t always a necessity. However, they would be quite useful if you deal with a lot of low torque and tight clearance. The screwdriver key would be best for adjusting disc brakes lever reaches or bottle cages.
The Ratchet Allen wrench is available in multiple varieties. The ideal type for bicycle maintenance will usually have replaceable bits and not actual sockets. This in turn helps to give the tool a shallow profile. If you are looking for speed, then a ratchet would be the ideal for you. However, if you deal with a variety of bike sizes, you might need to swap between multiple sizes.