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trail addict
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Discussion Starter · #1 ·
this was posted in the drivetrain forum, but when nobody responded, I figured my questions might get a better response here...

My new chain (installed at LBS) is way longer than necessary. I would like to get it shortened to the point where I can run big/big without damaging anything AND have a spare link or two in case of problems on the trail. That would mean taking out like 8-10 links, I think.

Question 1: Does using a chain breaker hurt the strength of the chain? I used a chain breaker on my old chain and in its final day it blew apart 4 times (although that old chain had other issues as well that may have stressed it out)! Any advice?

Question 2: Is there some kind of rule for the chain tension "preload" screw (I don't know what else to call it) as you shorten a chain? I assume I should just turn it in enough to keep the tensioner from doubling over completely when I am in little/little. Is it more complicated than that?

Thanks for any advice!
 

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The way I size a chain is to run it on both the big cogs. Get the rear deraileur to extend to it's max, add 1 link and away you go. When you use the chain break besure not to press the pin all the way out of the outter plate, it will make reinstallation very hard. Check the chain for stiff links. If you do have a stiff link, which usually happen when you shorten or install a new one, just flex the chain side to side to loosen it up. You could also use a quick link instead of using the break to put the chain back together. good luck.
 

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if it's a Shimano chain, push the pin all the way out and repair it with the appropriate pin ($1 at the lbs...9sp is shiney, 8sp is dull/ black, 10sp has 3 lines).

if your chain is 8 - 10 links too long and a shop installed it, i'd take your bike back and get your money back on the labor. those guys are idiots, apparently. though, running spare links on your chain will also leave it too long. invest in a Power Link, instead, and if need be on the trail, avoid big/ big.

chain tool doesn't compromise the strength of the chain if repaired correctly.

not sure what you're referring to in question #2...the b-tension screw?
 

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You need to miss the rear derailleur out when sizing a chain. Go around the biggest two gears and add two links (one inner and one outer).

Consider finding a different shop.
 

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I always incorporate the rear derailleur when sizing the chain, And it always comes out fine. Before we go calling the shop rats at the LBS idiots lets be sure the chain is sized incorrectly.
 

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trail addict
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Discussion Starter · #6 ·
the Inbred said:
if your chain is 8 - 10 links too long and a shop installed it, i'd take your bike back and get your money back on the labor. those guys are idiots, apparently.

invest in a Power Link, instead, and if need be on the trail, avoid big/ big.

chain tool doesn't compromise the strength of the chain if repaired correctly.

not sure what you're referring to in question #2...the b-tension screw?
Well, I didn't pay for labor since the old chain had some issues when it was only a month old... and in all fainess, it would probably be a fine length for most mt bikes with a 42 tooth big ring (I have 2x9, so my big is only 36)

I think I have a power link (gold).. does it work like a master link? I would still need to break the chain to shorten it though, right?

The preload screw I am talking about is the one that "stops" the deraileur at it's slackest setting, turning the screw in rotates the deraileur back and loads the tensioner more (kinda like the spring tension adjuster screws on v-brakes).

Thanks
 

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If you're doing 'big-to-big' to determine the length of your chain, it will end up too long if you take it through the rear mech. Not so much of a problem with one ring up front, but I can't see how you'd be able to avoid shifting issues in the middle and, especially, the inner front rings. Check out Park Tool for three different methods for sizing your chain.
 

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Vaginatarian
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1 problem with running it through the deraillier is you have to deal with the spring tension of the deraillier and the adjustment the op is talking about is another variable. the standard practice is no deraillier, big big + 2 links. your method might work for you but you're the only one I've ever heard of using it.

Yates , if the lbs installed the chain and charged you to do it, they should have cut it to length. goto the Park tools site and look at the deraillier adjusting page it explains the adjustment you asked about, they also recommend the chain method above
 

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i notice the Park site leaves out two methods -

Big ring, little cog, pulleys inline

and

Little ring, little cog, chain through rear deraiileur with as little tension as possible w/o being slack.

they should all give the proper length. i prefer big/ big + 2 links, but use the big/ little, pulleys inline when questioning the length of the chain (w/o wanting to going into big/ big).
 

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trail addict
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Discussion Starter · #11 ·
Well, now I know what that little screw (B screw) is called...

Anyway, I was way off, when I straightened the pulleys and saw all that slack, I figured I'd be cutting out a serious hunk of chain (the 8-10 links was an estimate only), when I actually did it today, all that slack was only 4 links (2 inches), even after tweaking the B screw a little.

Thanks for pointing me to the Park Tool site-lots of good stuff there.

And no-I wasn't charged labor for the job, only the price of the chain.
 

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Double-metric mtb man
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I usually leave derailleur adjustments out of the equation until the chain is the proper length.

Myself, as I run Shimano chains, I ususally leave the chain running through the derailleur for sizing. Once I have found the right length for a bike, I have a 2nd chain for rotation (less wear on the chainrings and casette) and use it for sizing the next one for that bike...after all, if it ain't broke, why mess with it more, right?

As for sizing technique, I either use the Park Tools version or Atwood's from Mountain Bike Maintenance as I have had good experiences using both methods.
 
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