How a Rear Derailleur Works

In order to service and fine-tune the rear derailleur, we need to first understand how it works. This video will explain the function of each component that makes up the rear derailleur system, including the pulleys, barrel adjuster, limit screws, and index shifter.

Questions or comments? Leave them below!

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➤ About Park Tool:
Since our founding in 1963, Park Tool has been the leading name in bicycle tools. Our YouTube channel is an extension of our mission to be the ultimate resource for mechanics and riders of all skill levels. Here you will find comprehensive repair help tutorials for a wide range of components and processes, as well as troubleshooting guides, tips and tricks, and information on the latest Park Tool products.

➤ More Derailleur Repair Help:

[MrTomfooligans]

It's so uncommon and satisfying to watch a video whose makers clearly understand how to illustrate mechanical concepts visually. The notion to leave graphic markers to indicate progress, travel, minimums and maximums is brilliant and so cleanly done. I struggle with abstract thinking and so these guides perfectly help me keep up with the mechanisms being described. Thank you.

[breichard]

These videos are a brilliant public service for amateur mechanics. Thanks Calvin and Park Tool!

[timmothycopeland]

These videos should be shown to all kids, boys and girls, one summer between 5th & 6th grade as a required summer project.

[vaux_manvv]

The quality of the videos are just insane. This is why I love park tool instructions and tools. Calvin is a super awesome too. I am an designer/artist by hobby so you can only imagine how impressed I am with the little touches such as the blue colour to show different parts of the derailleur etc

[pagetvido]

Love the way you explain and visually highlight the information. Excellent video.

[mihaillefterov]

What really makes a difference is the actual knowledge of how mechanical systems work, and that is where Park Tool stands out ! As a true bike lover i take my classes at the Park Tool channel ! Thank you Calvin .

[sakkarugzo]

Park Tool...you got one of best prepared videos I have seen. You definitely know your material and surely know that your audience may know very little about bikes. You use those visuals really productively to close the gap between your explanation and the people like myself who are trying to get a clue. I did my first triathlon last summer after tuning my bike by myself while watching your videos. Continue the good work!

[schneefoen]

not least because of these very helpful videos it doesn't bother me to pay more money than elsewhere for park tool's high quality tools. thank you very much!

[andersbjorkman]

I bought a park tool-tool to support you since your videos are so helpful and have saved me a lot of dollars through the years :) You deserve every dollar you get! Cheers

[bengunn]

Concise and to the point. No waffle no attempted humour as in many YouTube videos.
Ten out of ten. Thank you.

[ChrizK]

A cycle distributor from the UK directed me here as I am having problems with the gears 'out of the box'. Wow, what an incredibly clear video ...true professionalism. Fabulous. Wish I had seen these years ago.
49 Dislikes ?!??! Even someone who can't speak English should surely appreciate the excellent video production. Perhaps they want a video for the blind as well?!?!

[thejohnleos]

This has to be one of the absolute best videos illustrating a concept, ever. Outstanding job guys.

[koagzero]

You are a legend. I love these videos showing the parts in action with the front and side view. Very clear visual rundown on everything.

[LEOMX]

This is like bike mechanic school for the uneducated ( like me) it could not be explained any better. The graphics any production are first class. Absolutely amazing job on all the video’s 👌🏼...thanks.

[pmarcum]

This video is the most informative explanation and demonstration of the functionality of rear derailleurs that I have ever seen. I used the video settings to slow the speed of the video down in order to not miss any details (I turned off audio and turned on the captioning). I very much appreciated the use of the blue graphic overlays that highlight the components being referenced. Absolutely brilliant and highly informative -- thank you!

[MrSharkWalsh]

Perfectly explained and very to the point. I learned more in this 4 minute video then I did in an hour of researching other websites. Thank you!!

[dlads]

Honestly, from someone who knew how to jump two cars on a BMX and wheelie for over a mile, getting a bike in my 30s this video has been the most invaluable video I have seen, period. 2nd to none, so thank you and here's a like and a sub.

This is specifically how videos for bikes should be made.. slowly and on point.

Absolutely superb video.

Thank you..

Perfect.

[TrevorAllen]

This video is awesome.
While I don't bike myself, I'm a curious person, constantly struck wondering how thing around me work. My latest obsession was how a bicycle gear system operates in the third dimension -- ie how does a purely mechanical system release tension, move the chain, and then reapply tension with a new gear ratio.
This video does an *incredible* job of explaining the pieces involved, what they're called, how they work, what they do, etc., and does an even better job at providing a visual depiction (with simulated highlighting) of the relevant pieces doing what they do.
Coming from a physics-educated individual: this is a very good quality video for teaching people both what a rear derailleur is and how it works.

[johnbarwick]

Just the best video I've seen explaining the derailleur great work thanks.

[snakeubowski]

I can't thank you enough for all these professional educational videos. I really appreciate it!