How to Size a Bicycle Chain

Replacement chains for bicycles are always longer than you need. This video will take you step by step through sizing a bike chain, including determining whether your old chain was correctly sized, sizing to an old chain, and the largest cog & chainring method, as well as some exceptions and considerations such as rear suspension and chain guides.

Questions or comments? Leave them below!


Video contents:
00:39 Tools Needed
00:57 Check & Remove Chain
02:57 Sizing to Original Chain
04:01 Sizing to Largest Cog & Largest Chainring
06:26 Exceptions & Considerations

➤ Tools & materials used:
• New Chain
• Marker


➤ Fix It:
Did you know that Park Tool is the #1 resource for bicycle repair education?

➤ 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 Chain Repair Help:

[wadebesack]

If there were awards for YouTube videos, Park Tool would win hands down in the "How-To" category. They are clean, consistent, professional, clearly scripted, well organized, step-by-step...I could go on and on. Excellent way to promote the purchase of high-end tools and ensure happy customers after the sale, having empowered them to do the job right. If I owned a bike shop and hired a new mechanic or had an employee wanting to transition into that position, I would point them to the Park Tool channel and say "watch every video, then we'll let you start touching the bikes". Great as usual.

[Braindead]

As a total beginner I have watched many Youtube videos. I have to say that your site is the most uderstandable site to watch. You use simple, easy and precise language, without all the unnecessary waffle that I see on many other videos. Thank you for a site that I can understand and follow with ease.

[HardwareUnknown]

Calvin is this best bike service teacher I've found on YouTube. I've nearly finished replacing my entire drivetrain for the first time from his videos. Others have said it before; this is the kind of value added benefit that a company can do to make me want to support them by buying their products. Granted it would be one thing if the tools were awful, but Park Tool stuff has consistently held up much better than cheap alternatives. For the premium, I'll take the better tools and support the consistently professional videos. Thanks Calvin and Park Tool!

[lumpythefish]

Honestly... the single best How-To vid I've ever seen on You-tube. Kudos to everyone who worked on this gem.

[redrocker]

Park Tools are expensive, I get it. But everyone should try to purchase at least one item from them to show appreciation for the knowledge they share we these videos. Park Tools and RJ The Bike guy are the two quintessential Youtube channels every cyclist should follow.

[masaharumorimoto]

THANK YOU! Just completed my 1st sizing a new chain, delinked 5 links and it was a complete success :) Chain looks perfectly sized now and no more loosy-goosy :)

[David..]

See you in a few months when I forget this shit again for the millionth time.

[MichelOcampo]

this video wasnt really what I was looking for because I was searching for the wrong thing BUT I must accept that I watched the whole video just because of the good quality of it, I was suprised of how well explained it was, highlighting and showing examples of your explanation, just perfect! I wish there was more channels (tutorials) in youtube like yours.
well done sir

[trekimpossible]

My road bike has Shimano system. I followed the instructions, especially the way 4:02 for chain sizing, to replace the chain myself. Went out to ride for 40 miles with 2000 feet elevation gain, no problem. Thx for the tutorial.

[kenm]

Thank you. These videos are incredibly helpful when I go to do maintenance/repair and the technology changes. Also, I started acquiring tools from Park when I was working in bike shops in HS and college. Now in my 40s, they still work great, still have warranty, and have been worth every penny.

[reggier]

This really helped me. First time replacing a chain. Tiagra 10s. Before I watched THIS video, i watched another video and I didn't pay attention to the details. I opened my new chain wrapped it around the sprocket and the cassette put the pin in and linked the new chain. Couldn't figure out why the chain was so loose. LOL So realizing my dumbness, and that I couldn't reuse that pin, I ordered a set of pins. In the meantime I found your channel. I watched the chain install and chain resizing 5 times each. Resized the chain, installed the new pin. Everything is good. Going to watch the videos on rear-derailleur adjustments and then ill hit the road. You guys also showed me that my brand of bike tools where trash.

[tomaskotulek]

Great video! After days of reading of "how to size the chain" I'm finally able to do it by myself without a fear of doing something wrongly. Thank you.

[virkelie]

What I like about these Park Tool videos and Calvin Jones is that the repair videos are very clear and specific. For instance other videos also say to add 2 links in sizing a chain; - but are unclear how to count a link. Calvin Jones is very specific and clear, so that you don't need to guess how to count 2 links.

[tonydeady]

This is the best video on chain sizing! Clear and precise instructions and explanation. I watched about six videos before this one and they all left me more confused than when I started. From one teacher to another, thanks!

[scottsprojects]

4:00 Sizing: Largest COG & Largest Chaining Method is what I needed. Thank you!

[celticwinter]

If people want to know how to make good "how to" videos, they should look at this series. Cutting, illustration, guidance and explanation. Just excellent.

[bakedpotato]

Thank you so much Mr. Calvin Jones and to the park tool team! You've helped me so much to the point I'm capable of being able to independently service my bicycle!

Thanks to your wide array of impeecable video guides, I was able to get a blown inner tube replaced when I was at least 10km away from the nearest bicycle shop!

Another incident, I was able to cruise back home with a bent derailleur hanger from a crash, by readjust my derailleur indexing and limits!

Besides, I just got my bicycle chain resized to have less chain slap and probably reduced 10 grams of chain's weight! After learning how to correctly cut and size the chain here 😊😊

[Mindaugas_]

after washing this :D I will try to repair my bicycle for sure. It rested 2 years in the cellar but now it won't. Wish me luck :D

[DJKLIBRA]

Thanks to the people of park tool I had no issues replacing my chain after my old one snapped in two yesterday. Threw it in the bin at the side of the road so had no comparison for my new chain. Very calm and clear instruction. Measure twice, cut once. Instant succes. Thank you Park Tool! By the way, your chain cleaner device also works like a charm, so as your Alan keys. Quality guaranteed with Park Tool. Greetings from a very satisfied customer.

[johnhenrick]

I note the 563 down votes and I wonder why. Are those down voters more knowledgeable or better mechanics than Calvin? He makes excellent videos, the very best! I appreciate his clear, concise instructions.