Length of the chain?

Discuss light weight issues concerning road bikes & parts.
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TonyM
Posts: 2025
Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

Hi,

Would the length of the chain (Dura Ace 11 speed or Sram 11 speed) have to be changed when switching from 52/36 with 11-28 to 50/34 with 12-25?

The chainstay is: 405mm (specialized Tarmac disc)

Is there any online tool where I can calculate that?

Tony
Last edited by TonyM on Mon May 15, 2017 6:38 am, edited 5 times in total.

sungod
Posts: 1504
Joined: Fri Dec 24, 2010 9:37 pm
Location: it's raining, it must be uk

by sungod

in this instance you can be sure the chain won't be too short as the largest front/rear are both lower than current

that leaves the difference between 52/11 vs. 50/12, which i don't think will trouble you

but, you will have a chain longer than you really need, shortening it can reduce the chances of slack chain hitting the chain stay on rough surface

madik
Posts: 75
Joined: Sun Jan 08, 2017 12:44 pm

by madik

It will work but might not be ideal. Specially if you have a short cage RD. With medium/long cage you woudn't have probably noticed a thing.

slick1
Posts: 211
Joined: Wed Nov 30, 2005 1:35 am

by slick1

Going by this ratios you might be a few links too long.

When you are in 34/12 is there any sag in the chain and is the rear derailleur in the fully retracted position?

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alcatraz
Posts: 859
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Chain should work but it's longer than you need. You got only a 1 tooth decrease of your slackest gear (12+34 vs 11+36) but a good 5 teeth in the biggest diameter gear (28+52 vs 25+50). One link should probably be removed. Possibly even two.

/a

savechief
Posts: 305
Joined: Wed Aug 31, 2011 2:36 am

by savechief

This calculator puts those two combinations at 2 inches apart:

52/36 + 11-28 = 54 inches
50/34 + 12-25 = 52 inches

http://www.machinehead-software.co.uk/b ... hcalc.html
Time VXRS Ulteam (7.16 kg)
viewtopic.php?f=10&t=120268

2lo8
Posts: 368
Joined: Thu Mar 31, 2016 10:32 am

by 2lo8

Setting chain length by small-small instead of big-big usually gives you the most cassette compatibility if you're the type to swap out cassettes.
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boots2000
Posts: 1428
Joined: Mon Oct 15, 2007 9:28 pm

by boots2000

This^^^^

2lo8 wrote:Setting chain length by small-small instead of big-big usually gives you the most cassette compatibility if you're the type to swap out cassettes.

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