big/big plus 2 chain measurement
04-16-16, 05:20 PM
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big/big plus 2 chain measurement
Hello , just fitting a Shimano 11 speed chain on a 50/34 compact with 12/32 cassette. Shimano says big/big plus 2 . Anyone have experience with this configuration ? Hate to cut it too short.
Thanks , Frisky
Thanks , Frisky
04-16-16, 05:24 PM
#2
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I run the same combo as you and the big/big + 2 method works for me.
04-16-16, 05:53 PM
#3
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works for me too.
My OE chain came about 3 links too long.
I cut it down to big-big plus two.
My OE chain came about 3 links too long.
I cut it down to big-big plus two.
04-16-16, 05:56 PM
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Remember it's big-big+2 where the "2" means two 1/2-links or 1". Adding 2" (four 1/2-links) probably won't hurt but it's not necessary. Also, you loop the chain around the largest cog and largest chainring without going through the rear derailleur.
Finally, be sure the ends of the chain will join correctly, that is you need to have one male and one female end if you are using the specific joining pin or two male ends if you are using a master link. If the measured length winds up with a mismatch, add an extra 1/2-link to get the right configuration.
Finally, be sure the ends of the chain will join correctly, that is you need to have one male and one female end if you are using the specific joining pin or two male ends if you are using a master link. If the measured length winds up with a mismatch, add an extra 1/2-link to get the right configuration.
Last edited by HillRider; 04-16-16 at 06:00 PM.
04-16-16, 06:27 PM
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04-16-16, 06:28 PM
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Thanks all . I am going to get right on it . Frisky
04-16-16, 06:48 PM
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After you close the chain carefully check to ensure that you can shift into the big-big combination without straining anything. Do this by GENTLY turning the crank by hand. STOP if the chain gets tight, it is too short.
04-16-16, 07:26 PM
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Of course it's easier to measure a chain without fighting RD idler tension, so measuring w/o the RD makes sense, 'm just pointing out that it doesn't matter, and if it did, then you'd HAVE to measure including the RD.
BTW- BB+2 does not work for vintage derailleurs that are not slant parallelogram. Those still cal for measuring through the RD and pulling up available slack.
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
04-16-16, 08:29 PM
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Sure, but fighting the rd's cage tension spring makes getting the chain looped properly more difficult so why not avoid it? Obviously with and without using the rear derailleur in the measurement must not matter or you wouldn't be able to do it both ways.
04-16-16, 08:39 PM
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I posted to show the bigger picture, so that people understood a bit more. Some time back, I saw somebody destroy a mint condition vintage Nuovo Record derailleur because he followed this instruction by rote rather than thinking.
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An ounce of diagnosis is worth a pound of cure.
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“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
04-17-16, 07:07 AM
#12
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Excellent point but that would be a very rare incident these days. It does illustrate that dsbrandtjr's caveat to ".....carefully check to ensure that you can shift into the big-big combination without straining anything. Do this by GENTLY....." is very good advice to check that you've done the measurement and sizing properly and there are no other problems you missed.
04-17-16, 08:27 AM
#13
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I made a C* Bent out of a broken spoke to hold the ends, feed the chain over big-big & thru the pulley cage , to judge the needed length ,
By seeing what the chain loop looks like, before cutting .
*/__\
By seeing what the chain loop looks like, before cutting .
*/__\
