# Thread: Derailer and Chain Length

1. ## Derailer and Chain Length

I switched from a long cage XT to a med cage XT. Should I remove links? The chain is measured big/big rings plus 2 links with suspension distance taken into account. It seems alittle long.

2. Yes, you will need to remove a couple links if you are running a triple. If you are switching from a triple to double then re-measure your chain length in the big/big+2 combo.

3. Originally Posted by dhpimp
Yes, you will need to remove a couple links if you are running a triple. If you are switching from a triple to double then re-measure your chain length in the big/big+2 combo.
I apologize, this may sound dumb but some people use the word couple loosly and do not mean exactly 2. Please confirm that I would measure big/big + 0.

4. I read on these boards that the formula works for all derailleurs regardless of their lengths. So, big/big + 2 (no derailleur involved in the measurement.)

5. Originally Posted by Ouchies
I read on these boards that the formula works for all derailleurs regardless of their lengths. So, big/big + 2 (no derailleur involved in the measurement.)
I agree, both SRAM and Shimano say to use the big/big approach plus 2 links. You don't warp it around the derailleur when setting the length. This works fine on both my long and medium cage derailleurs.

Wombat

6. If you make your chain big/big+2, should you be able to shift to the big/big combo? I know you "shouldn't" do this but ...

My LBS installed a new chain and there ain't no way it will shift to big/big.

7. Anyone?

8. I'm interested for more response as well....as I've heard big/big+2 and have heard the "bottom-pulley-at-4o'clock-position -in-big/big" to measure chain length.

9. Originally Posted by WildJackal
should you be able to shift to the big/big combo?
Yes. That's the whole point behind the "big-big" method: just enough chain to safely shift to big ring and big cog and not break anything.

Like Wombat wrote, the derailleur isn't involved in this process, so cage length has no impact on chain length.

<img src="http://www.booboodog.net/images/chainlength.jpg">

10. just make sure your new derailleur won't be maxed out in the big/big setting (for safety's sake, but never shift there...). Break your chain, thread it thru everything while on the big/big gears, and pull it together by hand. You'll see when the der is stretched to max, then back it off a link or two...reassemble the chain at that point/length.

...you'll most likely find that it's about the same length as the standard big/big measurement mentioned earlier...for future reference.

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