Chain length

[Cormac O'Keeffe]

Hi,

I was wondering what your experience with chain length was. Since RBW frames have pretty long chain stays, what length chain do you tend to run?. For information I'm using a 48-38 in front and 11-34 at the back on a '24 Sam.

Cheers!

Cormac

[Ryan Frahm]

I’m have been using a KMC 10 speed e-bike chain. 136 links. I only removed 2 for my Clem with 34/24 rings and 11-42 cassette. As an extra bonus, they last forever!

[Wes A]

A big ring like that up front is going to require a long chain. With 118 links, I've got just enough for a Homer running a 34/24 and something similar for the cassette. E-bike chains are a good shout for sure: https://kmcchain.us/collections/e-bike-9-speed/products/e9

[DavidP]

My 60cm Platypus with 46t big ring and 34t big cog took 116+12 links. I used two 116 link chains and two quick links and kept the remnants of the second one for future use.

-Dave

[Bill Lindsay]

I always just use the St Sheldon method and use what I have to use, on whatever the bike.  big+big+2 links.  

Bill Lindsay

El Cerrito, CA

[Mike Godwin]

I second Bill's method, has worked for me on all bikes for decades.

Mike SLO CA

[Ray Varella]

Just to clarify my understanding and perhaps anyone else who isn’t 100% clear, the Big/Big plus two links is done without the chain running through the derailer, right?

Ray

[DavidP]

Yes - bypass the rear derailleur when wrapping the cog.

https://www.sheldonbrown.com/derailer-adjustment.html#chain

https://www.parktool.com/en-us/blog/repair-help/chain-length-sizing

-Dave

[Piaw Na]

Bill's method will not work for 1x. Shimano's specifications are big sprocket and chainring + 5-6 links.

[iamkeith]

Oops.  That's how I set up my 1x12 Shimano mountain bike drivetrain.  (Big/big+2links.)  Hasn't given me any trouble....  Unless bending the derailleur hanger when I got a branch stuck in the rear wheel was related - but I think that would have happened no matter what.

[J G]

Pretty sure you are all saying the same thing differently.

Bill's method is just fine I bet and is probably the same method as Shimano documents, but with a different baseline for what a link is, regardless of what is technically correct.  

I checked the Shimano site and they show every rivet as a link count where I suspect both Bill and I have always considered a link to be a full plate with a leading loop perhaps (2-3 links in Shimano doc).  The Shimano interpretation seems odd to me but what seems clear is the picture of their 5 links plus a quick-link looks like big/big+2 to me.  Next time I pull a chain, I guess I will verify if 116L is # of plates or rivets...whatever...

2 full plates and an open loop for my quick-link is always where I start and if I can remove a plate later to optimize, great, if not I am probably about perfect already.

I do also have 2 x 1x Hardtails and both were sized with what I define as big/big+2 per above and setup is about perfect.

Just my thoughts.  Hope that helps...

-Justus

Mpls, MN

[Cormac O'Keeffe]

Thanks to everyone for sharing their experience and advice on chain length and sizing techniques. It's all been very helpful. You've confirmed my suspicion that my chain was indeed too short — I'd taken a 116 link chain (mangled a link or two) and ended up with an 114 link chain. This meant that as soon as I was on the big chainwheel up front, once I went past 14 teeth in the back it locked up the transmission. 

One of the things they don't tell you, as obvious as it seems thinking back, is when you move the world of long chainstays, is that you are also in the land of long derailleur cables and long chains!

- Cormac

Paris, FR

[Cormac O'Keeffe]

Quick update for the curious. In the end, for a 48T big chainring and  34T rear sprocket on a 54cm Hillbourne, the chain length was 116 rivets + a quicklink. Almost standard chain-length but not quite.

[Garth]

The Omnicalculator works too. 

 https://www.omnicalculator.com/sports/chain-length

Or use #3, the math forumula. Most useful for overly long chainstays where the standard chain isn't long enough to begin with and will be added to. 

https://ilovebicycling.com/determine-bike-chain-length/