A misaligned hanger is often the main culprit behind poor shifting and a tweaked hanger will make it impossible to get your drivetrain running smoothly in every gear. All it takes is a bit of a knock from a rock or log, putting your bike down the wrong way, or a crash, and suddenly your gears are all over the place. The worst thing is that the hanger often looks fine but can be juuust wonky enough to make your gears skip a little and drive you insane.

Even brand new hangers are rarely totally straight and will need to be tweak a little when they are first installed, so having one of these tools handy will save you lots of head scratching and trips to the mechanic.

Who's this item for: This tool is for home mechanics that want to have everything they need to ensure their shifting is as crispy and smooth as possible.

How does it work: The tool threads into your hanger in place of the derailleur and is used as a pivoting point to measure the distance between the gauge and the rim at different points (normally 9, 12, and 6 o'clock positions). If the gauge isn't the same distance from the rim at each point, the arm of the tool is used as a lever to make small adjustments to tweak it back into place.

See the video below for more info.

Note: Hangers are made from aluminium and don't hold up well to a lot of bending. If the hanger is substantially bent you will need to replace it as the metal will fatigue and fail if you try to bend it back into place.

Compatibility: Works with most 20-29" wheeled bikes. Some bikes may have clearance issues depending on the hanger position and the placement of the suspension pivots but it's impossible to predict which ones will have problems.

Pros: Affordable alternative to the expensive workshop quality tools from Park, Abbey etc.

Cons: This tool will do the job nicely in most cases but you get what you pay for and it may not be as precise as those fancy tools that cost 2-4 times as much.