How to Size a Bicycle Chain

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!

See all our chain videos in our chain repair help playlist ▶︎

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:
• MLP-1.2 Master Link Pliers –
• CT-3.2 Chain Tool –
• CT-4.3 Master Chain Tool With Peening Anvil –
• New Chain
• Marker
• Repair Stand –
• See all Park Tool chain products –

For a text-based walk-through of this process:

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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:
• The Park Tool Guide to Chains ▶︎
• How to Clean and Lube a Bicycle Chain with a Park Tool Chain Cleaner ▶︎
• When to Replace a Chain on a Bicycle ▶︎
• How to Fix a Broken Bicycle Chain ▶︎
• How to Replace a Chain on a Bicycle – Sizing & Installation ▶︎
• How to Replace a Chain on a Single Speed Bike – Sizing, Installation & Tensioning ▶︎
• How to Size a Campagnolo Bicycle Chain ▶︎


  1. gabespartan on June 21, 2022 at 10:27 pm

    Question: why is it 4 rivets w/ a SRAM 1X? I currently have a SRAM 2X and want to switch to a 1X (same derailleur and a 50t on both), and the 4 vs 2 rivets does not make sense to me.

  2. Diego Steffaloo on June 21, 2022 at 10:30 pm

    Does this procedure works with a 1x system on a hard tail bike? It’s 9 speed btw

  3. Julius Caesar on June 21, 2022 at 10:31 pm

    might be overlooking something here but do you route the chain throught the derreilieur while measuring for a 1×12 drivetrain ?

  4. Joseph Michael's on June 21, 2022 at 10:31 pm

    How about rear suspension with three front gears.go with the big gear???

  5. Mark T on June 21, 2022 at 10:33 pm

    @Park Tool Do I have to do something different if I have a rear derailleur extender? I have a 10 speed mountain bike with rear suspension. I changed out the rear cassette for a bigger on (11-46). My derailleur is a Shimano Deore XT (long cage). There was no way I was getting on to the biggest gear, even with b-screw all the way in. So I had to get an extender. I also ordered a longer b-screw but that hasn’t arrived yet, not sure if I will need it though. Great video by the way!

  6. Nicholas Northam on June 21, 2022 at 10:34 pm

    Hi – great video, thank you. However, having followed the instructions to calculate chain length and installed the chain it was too short. I believe the issue is that I have a long cage derailleur and so adding the 2 rivets is not enough. I assume that I need to add more than the 2 rivets to cater for the longer cage – can you help? Thanks …

  7. christianb7 on June 21, 2022 at 10:35 pm

    Great video. Super clear and helped me do the job easily. Thank you

  8. Robin Hughes on June 21, 2022 at 10:35 pm

    Thanks so much!!! I actually have a single blue raceface chain ring with SRAM 11 speed cassette on my fat bike… without knowing about those two extra rivets I would have been a sad boy!

  9. karhu bear on June 21, 2022 at 10:35 pm

    Thank you

  10. Trevor Jansen on June 21, 2022 at 10:38 pm

    I love these videos. A wealth of knowledge surrounding bicycles. And as far as learning how to maintain something goes, bicycles are at the top of the list. One of the coolest inventions of all time.

  11. Matthew Shelton on June 21, 2022 at 10:41 pm

    Do you add two rivets for full sus bike with the chain running through the pulley wheels or just the chain on the largest cog and chainring??

  12. Synysterjmz on June 21, 2022 at 10:46 pm

    Does the same Sram rule apply to a Shimano 11 speed?

    I’m upgrading my hard tail from a box four 8 speed to Shimano 11 speed, so do I stick with the 2 rivet method, or add 4 instead?

  13. Hugo Torrez on June 21, 2022 at 10:48 pm

    Hello I need help, I’m new to this and I’m trying to figure out what speed my bike is, my bike has 10 cassettes in the rear which are 12/25t and the front has two cassettes which are 50/34 what type of chain do I need or what speed is my bike ?

  14. Gary G on June 21, 2022 at 10:49 pm

    Excellent Job… Very clear and easily understood. Thank you!

  15. Frank Leurs on June 21, 2022 at 10:54 pm

    I replaced the chain AND cassette. It was worn after riding for 11.000 km.
    I have a 9-speed on my bike. And use a masterlink-chain.

  16. Unitedeurope on June 21, 2022 at 10:55 pm

    The guy is just great. Just focused on the relevant stuff. No unnecessary talk. I only watch park tool videos – and then buy their tools 🙂

  17. grocerylist on June 21, 2022 at 10:58 pm

    What if you don’t have the old chain?

  18. Douglas Dye on June 21, 2022 at 10:58 pm

    Excellent, comprehensive video. Thanks very much Calvin!

  19. mas apri on June 21, 2022 at 11:00 pm

    Thank you 👍 This answering my confusion why my new chain is longer than my old one.

  20. Formal. on June 21, 2022 at 11:01 pm

    7:02 I have a 10×1 speed non sram derailleur and no rear suspension. Do i still add 4 links?

  21. MrChlorinated on June 21, 2022 at 11:01 pm

    Wish I would have watched this before over-shorening my chain and ripping off the rear derailleur!

  22. santa fe, bantayan island life on June 21, 2022 at 11:02 pm

    It seems wierd and risky not running the chain through the derailer to size a chain . There are different lengths . How is that included in the calculation ? Or going from a 3x to a 1x with much larger cogs added

  23. Songs And Verses on June 21, 2022 at 11:03 pm

    6:52 what if it has suspension? And not a single from chainring? Maybe 2 or 3 is there some math to determine?

  24. Chris Ferguson on June 21, 2022 at 11:04 pm

    So basically you would add four links to the reference rivet if you’re installing a chain on a bike with BBSHD/02 and a 11 or 12 speed rear sprocket.

  25. Colby Scott on June 21, 2022 at 11:06 pm

    Sooooo, aparently the full suspension method doesn’t work on the 2017+ Niner Jet 9 RDO’s. I did this method and went one link (two rivets) longer, just in case. Figured it’s easier to take links out than put them back in. In order to get full compression and the chain still maintain contact with the rear upper pulley, I had to losen the travel screw to the point that the chain rubs on the chainstay. If I adjust it so that the chainstay doesn’t rub, the chain loses contact with the top pulley about 3/4 into the travel.

    Then I took one more link out (which puts it in line with this video) and now I can’t get full compression at all because the chain gets too tight.

    Limit screws are set correctly and I’ve been back and forth with the travel screw (or whatever that screw is called.)

    BTW, I’m running a 32T chainring with a 9-46 cassette.

  26. Brend-Petter Løvaas on June 21, 2022 at 11:06 pm

    funny I always disassemble the master link by hand, I find it simple? must be something wrong with my KMC master links

  27. Alex Paulsen on June 21, 2022 at 11:08 pm

    "Replacement chains for bicycles are always longer than you need"

    Well, I just built a short wheelbase recumbent, and I can assure that a single chain was anything but too long.

  28. CRAIG OPPERMAN on June 21, 2022 at 11:08 pm

    For those who know nothing regarding bicycles, what does the master link look like?

  29. Samantha Garcia on June 21, 2022 at 11:09 pm

    what I’m a little confused about, is when breaking a chain that has a connecting rivet, why bother avoiding that rivet? is it in case you want to reuse that chain? but then that would make replacing it obsolete. and so to replace the chain, wouldn’t that make that connecting rivet obsolete? and therefore unnecessary to avoid? I feel like I’m missing something here and I just have no clue what that thing is. love the videos otherwise!!!! definitely helpful for routine maintenance🥹

  30. Robert Boswell on June 21, 2022 at 11:10 pm

    Would this be the same procedure when a over sized pully wheel is fitted to a road race bike?

  31. Florin Sirbu on June 21, 2022 at 11:10 pm

    Great stuff, thank you. I tried sizing my new chain using the old one and to be sure I used the Largest cog and the chainring ,( 1×11 setup), method and the length was different. I wonder if I missed something as I was expecting to get the same length using two different sizing methods.

    Kind regards,

  32. Killroy76 on June 21, 2022 at 11:11 pm

    Worked like a charm. Thank you

  33. zedrick murro on June 21, 2022 at 11:11 pm

    thanks for this channel, its very helpful

  34. KrisAlex on June 21, 2022 at 11:12 pm

    Usually i route the chain trough is proper path, trough the derailleurs, while they are set to small-small. i allow the longest chain possible. pulling the chain rivet by rivet until i get any tension from the derailleur. the moment i feel the slightest tension, that’s the spot where i cut and assemble the chain. Works like a charm, the first time every time.

  35. #AkoSi- Bong on June 21, 2022 at 11:13 pm

    will these methods also apply to folding bikes? thanks

  36. The European Cyclepaths on June 21, 2022 at 11:13 pm

    I wish you lived in Cyprus. I’d bring my bike straight to you every time

  37. Ken Ken on June 21, 2022 at 11:17 pm

    Can I apply this technique even though my rd has an oversized pulley? Ceramic speed

  38. singbob on June 21, 2022 at 11:17 pm

    If I’m setting up my 1×12 with Shimano derailleur is it the same method as the SRAM 1×12 setup? The frame is a hard tail, in case that makes too much difference

  39. EEEEEE on June 21, 2022 at 11:17 pm

    So much better visually than the official SRAM video for eagle!

  40. John Q on June 21, 2022 at 11:19 pm

    @Park Tool 5:27 "add two additional rivets" Q: does this apply to Shimano 1x drive trains as well? Thx

  41. Dan Themann on June 21, 2022 at 11:20 pm

    Great video, you guys rock.

  42. Old Nightrun on June 21, 2022 at 11:21 pm

    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.

  43. Rado Hudran on June 21, 2022 at 11:22 pm

    thx for the tips! Pls eat some more you look unhealthy

  44. Fuad Persie on June 21, 2022 at 11:22 pm

    Can someone tips me I’m using 8 speed but upgrade the teeth to 11-40t, should I change the chain to 9 speed instead 8 ??

  45. Posa Negative on June 21, 2022 at 11:23 pm

    Ive got a question if my 1 by 8 chain broke can i get another 1 by 8 chain with different brand or do i need the same brand chain

  46. Cristopher Altobranto on June 21, 2022 at 11:23 pm


  47. Dave Rich on June 21, 2022 at 11:24 pm

    I noticed that when breaking the chain using the chain breaker that the river was pushed out the other side of the link. I find this hard to get back in when reconnecting. It’s possible to push the rivet enough so it stays in the far plate, but allows the chain to be disconnected, this is much easier to reassemble.

  48. Brad McDorfhead on June 21, 2022 at 11:24 pm

    Damn helpful video. Well done.

  49. smarc 13 on June 21, 2022 at 11:24 pm

    very helpfull… THNX

  50. Vern Frier on June 21, 2022 at 11:25 pm

    I have a Sram road bike set up with a 1×10 / 11-40 cassette. Do I use the 4 rivet rule for this system?