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Discussion Starter · #1 ·
Sorry for being anal-retentive about this but I can't help it. This is a new build and when I did the chain length formula I was between 55 and 54 inches. I went with the longer option. It shifts fine but in the small-small combo there is very little slack. First picture is small-small combo, second is big-big. Thoughts?

Wheel Bicycle tire Bicycle wheel rim Bicycle part Spoke
Wheel Bicycle tire Bicycle wheel rim Bicycle part Spoke
 

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perfection
 

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'brifter' is f'ing stupid
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Don't bother doing math to size your chain. Your chain is perfect. Just put it on the bike and do exactly what you did. Done.
 

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Discussion Starter · #7 ·
Don't bother doing math to size your chain. Your chain is perfect. Just put it on the bike and do exactly what you did. Done.
Thanks everyone for the advice/confirmation. I was a bit worried about sizing because I am going with the Campy medium cage derailleur and a monstrous 32t rear cog. A few years ago I was building up a new bike and I trusted the chain "formula". The chain ended up too short and I had to buy another chain
 

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A few years ago I was building up a new bike and I trusted the chain "formula". The chain ended up too short and I had to buy another chain
Maybe it's a too-obvious question: Why do you continue to use a "formula" that you know doesn't work? Or did you use a different formula this time?

As others have noted, there is no need for a formula. Put the chain on the small ring and the smallest cog and then take out enough links so the derailleur just starts to tension the chain. That's the right "formula." And it looks like you are pretty close. One more link and your chain might be hanging loose.
 

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Discussion Starter · #9 ·
Maybe it's a too-obvious question: Why do you continue to use a "formula" that you know doesn't work? Or did you use a different formula this time?

As others have noted, there is no need for a formula. Put the chain on the small ring and the smallest cog and then take out enough links so the derailleur just starts to tension the chain. That's the right "formula." And it looks like you are pretty close. One more link and your chain might be hanging loose.
The answer is I tried the formula, and the Big-big approach than Zinn suggests and then I decided not to trust either. I cut the chain a little longer and put it on with a missing link to see how it looked figuring I'd cut it down if it wasn't right.
 

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I've always done the big-big going around only the cassette and the chainring bypassing the RD then add 2 links. Then route normally and either put the pin in or masterlink. Worked fine for me so far.
 

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'brifter' is f'ing stupid
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I've always done the big-big going around only the cassette and the chainring bypassing the RD then add 2 links. Then route normally and either put the pin in or masterlink. Worked fine for me so far.
As some of us have posted dozens of times, this works pefectly if you either 1) never change the range of your cassette, OR 2) you size the chain w/ the biggest cassette the derailleur will handle.

But, it's more of a pain to actually do it this way. It's easier and quicker to do small/small, but whatever floats your boat is fine.
 

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As some of us have posted dozens of times, this works pefectly if you either 1) never change the range of your cassette, OR 2) you size the chain w/ the biggest cassette the derailleur will handle.

But, it's more of a pain to actually do it this way. It's easier and quicker to do small/small, but whatever floats your boat is fine.
Ah, I see. Yeah I run the same cassette on all of my road bikes and cross bikes. I even go as far as running the same series cassette on my spare wheels and to make sure the spacer is the same thickness so that if I do need to swap a wheel out during a race the chance of me needing to trim the RD is minimal.

Once again though, that is probably more so due to my OCD kicking in at times.
 
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