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New Crankset, Longer Chain?

Old 05-07-21, 04:53 PM
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twowheelies
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New Crankset, Longer Chain?

I am going to switch out the compact crankset on my bike to a normal 53/39, both shimano 105 R7000. I think that would require a little longer chain, yes? How do I determine how much longer?

also, there is a KMC chain on there now, should i stick with that? I have a SRAM with the power link on my other bike and no problems...

thanks

-Joe
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Old 05-07-21, 05:31 PM
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So the big/big combo determines the minimal chain length. Assuming the current big ring is a 50T and given your stated 53T goal it would seem that 1.5 links (of 1/2" each) will take up the added 1.5 ring teeth the chain will need to wrap around. Of course chains for derailleur systems can only be changed by 2 links (of 1/2" each).

I suggest placing your current set up in the big/big and seeing who much spare chain length (or not) you currently have. It's easy to fold up a pair of links (of 1/2" each) to reduce the effective chain length by nearly 1". This gives you more data with the current set up and might help you see if there's enough chain to handle the larger ring as is.

But since you will be replacing the chain if now now then sometime in the foreseeable future I would just get a second chain to have on hand just in case after the crankset swap out you fine a longer chain is better/needed.

As to what chain to get... I'm a SRAM guy but KMC makes good enough chains too. Andy
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Old 05-09-21, 01:10 PM
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Originally Posted by Andrew R Stewart View Post
So the big/big combo determines the minimal chain length. Assuming the current big ring is a 50T and given your stated 53T goal it would seem that 1.5 links (of 1/2" each) will take up the added 1.5 ring teeth the chain will need to wrap around. Of course chains for derailleur systems can only be changed by 2 links (of 1/2" each).
Since the chain only wraps around half the chain ring (approximately). I concur.
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Old 05-09-21, 02:08 PM
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Good call guys thank you, makes total sense to try the existing chain first. Much appreciated
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Old 05-10-21, 07:44 AM
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Use the equation at the park tool website. A 3T increase requires 3/4 inch of chain, but changes can only be made in 1 inch increments or two links, so it should require 1 more inch. A link is 1/2 inch long.

https://www.parktool.com/blog/repair...-length-sizing
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Old 05-11-21, 12:06 PM
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Is there somewhere consolidated to review/research stuff like this? I am mechanically inclined, but I just don't have any experience working on bikes, and I'd like to do a bunch of part swaps. First in I'd like to replace the crank set including arms and pedals, but I can't even identify the part i have on Sram's website and despite the wealth of information on this forum, I can't seem to find anything through my searching.
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Old 05-11-21, 01:24 PM
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Sheldon Brown's website is excellent (newbie can't post a link).
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Old 05-11-21, 02:12 PM
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parktool.com has a lot of repair info.
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