Extra long tourer chain

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Vetus Ossa
Posts: 1051
Joined: 22 Oct 2012, 7:32pm
Location: London, Paris, New York but mostly Plymouth.

Re: Extra long tourer chain

Postby Vetus Ossa » 29 Aug 2018, 2:22pm

Have to agree with the above. Even if you never “intentionally” select big ring, big sprocket, the chances are one day you will and as mentioned, that is not a good thing.

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Mick F
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Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Extra long tourer chain

Postby Mick F » 29 Aug 2018, 2:26pm

I have 116 links on Moulton.

114 links on a Campag chain include a special outer link.
Get rid of that!
Now 113 links, with an inner link at both ends.

Take two quick links. These are outer links of course.
Take an inner link from a spare set of links. Be careful it will fall apart.
Fit one quick link at one end plus the spare inner link.
Take the other quick link and join the chain.
Hey presto, 116 link chain.

I did this to make a 118 link chain by using three spare links - one outer plus an inner at each end - and used two quick links as before with the 113 links.
Mick F. Cornwall

NetworkMan
Posts: 512
Joined: 25 Aug 2014, 11:13am
Location: South Devon

Re: Extra long tourer chain

Postby NetworkMan » 29 Aug 2018, 2:38pm

KTHSullivan wrote:Try this, I have always found it to be "in the parish"!

http://www.machinehead-software.co.uk/b ... hcalc.html

You can do it without any of these new-fangled aids!
Take one steel rule, one pencil and the back of an envelope. :)
For all common varieties of bicycle in units of links:-
Half way round the largest sprocket + half way round the largest chainring + twice the chainstay length + 2 links, rounded up to an even number.
If you deliberately use big to big - not a good idea - then add 4 links not 2, to save some strain.
My tourer has 17.9 inch chainstays, 48T big ring and 34T big sprocket
so it needs 17.9*4 + 48/2 + 34/2 + 2 = 114.6 links so round up to 116 links.
I bought a KMC since it had 116 links.

KTHSullivan
Posts: 111
Joined: 4 Aug 2017, 1:15pm
Location: Wind Swept Lincolnshire

Re: Extra long tourer chain

Postby KTHSullivan » 29 Aug 2018, 3:42pm

Just remember, when you’re over the hill, you begin to pick up speed. :lol:

NetworkMan
Posts: 512
Joined: 25 Aug 2014, 11:13am
Location: South Devon

Re: Extra long tourer chain

Postby NetworkMan » 29 Aug 2018, 3:56pm

KTHSullivan wrote:http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html


QED!

Yes, I'd expect it to agree. The error in the quick and dirty method only becomes significant when the chain is running far from horizontal so that the chainstay length approximation is not near enough. For that you need a relatively tiny biggest sprocket which is unlikely. edit:- or short chainstays.

Is gaz, king of search, here? I vaguely remember on the old CTC site there was a hideous account of someone trying to select big-to-big by mistake with consequences beyond a 'simple' jam. I can't find the reference though.