There is no single task more crucial to the performance of your drivetrain and the integrity of your frame, rear wheel and rear derailleur than proper alignment of the rear derailleur hanger. Any bike with a thread-in hanger can be checked and adjusted for alignment, and this should be inspected at every bike service. A leaning or falling bike can easily tweak the hanger, especially aluminum versions, as can transportation or careless storage. An improper alignment can easily result in an overshift that damages your frame, rear wheel, derailleur and chain. Shimano's TL-RD11 Rear Dropout Alignment Tool is the best alignment tool we have used, and though it may seem pricey, add up the cost of a rear wheel rebuild, derailleur and chain- you'll find the tool will easily pay for itself. You notice the frame price wasn't included in there? Every cyclist who services their bikes at home should have the TL-RD11. Not only is it the best such tool, it is easy to use and precise for bikes with wheels from 20-29".

Shimano uses heat-treated high grade carbon steel as the stock for this tool. It is precisely made and will resist torsion and damage that could alter it's accuracy. The finish is a chromed which not only looks great, but also protects the tool from corrosion. Shimano delivers a scale, with precise numerical measurement on the rotatable extension. This allows you clear the frame and chain with ease, as well as maintain perfect measurement from one position to the next as you check and set alignment. An indexing system allows the scale to return to the exact measurement after rotation.

The ergonomic handle is easy to use, despite the tool's heft, and the overall design is telescoping for ease of use with small wheels, as well as more compact storage. The main knob is used to thread in M4 steel bolt into the female hanger opening. It should always installed so that the billet sits flush against the hanger. Every aspect of this tool has been thought through for accuracy, ease of use, and proper use. We highly recommend that anyone who uses a rear dropout/hanger alignment tool get proper instruction in use. Replaceable hangers and fixed dropouts can come in steel, titanium, and aluminum, and some care and experience is required so that you don't damage or weaken the hanger. Most hangers should be visually inspected for cracks or damage before tool use, bolts tightened (if applicable), and caution must be used when threading in the TL-RD11. If a hanger, especially an aluminum replaceable model, feels flexy or bend under very little pressure, it should be replaced.

All hangers should be checked and aligned when a bike of frame is new, as should any hanger that is being replaced. Ideally all hangers should be manipulated as little as possible, but again, alignment is absolutely crucial to rider and equipment preservation. Create the best possible platform for your drivetrain with the TL-RD11 Rear Dropout Alignment Tool from Shimano. Your goal is to never have a problem or failure and it starts with the best tool for this application.