Chain length question

[Tdwfl]

I'm getting ready to change my first chain ever. I've read the instructions which seem
straightforward however it seems like if you wrap it around the big-big and add 1 link, when you
were in the big-big and through the derailer, the derailer would be pointing almost straight
forward. It seems like no bike I've ever owned was configured this way or maybe that extra 1 link
adds a lot more slack than I'm thinking it would. Do OEMs size their chains the same or do they tend
to be on the loose size to allow for different size rear cassettes?

Tim

 

[Jobst Brandt]

Tim DWFL? writes:

> I'm getting ready to change my first chain ever. I've read the instructions which seem
> straightforward however it seems like if you wrap it around the big-big and add 1 link, when you
> were in the big-big and through the derailleur, the derailleur would be pointing almost straight
> forward. It seems like no bike I've ever owned was configured this way or maybe that extra 1 link
> adds a lot more slack than I'm thinking it would. Do OEMs size their chains the same or do they
> tend to be on the loose size to allow for different size rear cassettes?

Don't bother with formulae and rules of thumb if you have the old chain that worked OK. Just replace
it with a chain of the same number of links. You can do this by laying the new chain on its side
next to the old one (that will be longer) and run your fingers pinching them together over their
length so that they match link for link and lop off the excess of the new one.

Jobst Brandt [email protected]

 

[Pete Biggs]

TDWFL wrote:
> I'm getting ready to change my first chain ever. I've read the instructions which seem
> straightforward however it seems like if you wrap it around the big-big and add 1 link, when you
> were in the big-big and through the derailer, the derailer would be pointing almost straight
> forward. It seems like no bike I've ever owned was configured this way

A lot of bikes have chains that are longer than necessary. I'm not quite sure why.

> or maybe that extra 1 link adds a lot more slack than I'm thinking it would.

I suggest starting off with a chain that is definitely a bit too long (full length or guess or
big-big without der. + two links), thread it through the derailleur and join, then remove one link
and repeat until you are statisfied that chain is a short a *reasonably* possible for the big-big.

Bottom gear tends to work better with a short chain. Small-small combos work better with a longer
chain - but since small-smalls are not good to use anyway, the big-big method normally suffices.

See: http://www.parktool.com/repair_help/FAQchainlength.shtml

~PB

 

[David Damerell]

TDWFL <[email protected]> wrote:
>I'm getting ready to change my first chain ever. I've read the instructions which seem
>straightforward however it seems like if you wrap it around the big-big and add 1 link, when
>you were in the big-big and through the derailer, the derailer would be pointing almost
>straight forward.

That's not a problem, especially since you won't be riding in the big-big, right? But if the
previous chain worked fine, use the same number of links.
--
David Damerell <[email protected]> Kill the tomato!

 

[Flatline]

When you measure the chain, don't thread it through the derailleur. Do that only after you've got
the chain cut to the length and are ready to put the chain on. You'll get enough slack. Sheldon's
instructions at http://www.sheldonbrown.com/derailer-adjustment.html#chain work for
me.

These three sentences are worth repeating. Here they are:

"The best technique for setting chain length is to thread the chain onto the large/large
combination, without running it through the rear derailer. Mesh the two ends on to the large
chainwheel so that they could be connected (outer link meets inner link), then make the chain one
complete link (one inch) longer than that. In almost all cases, this will give the optimum length."

I'm not a professional mechanic, but I've done this on two road triples, a standard double
chainring, and a double chainring road bike with a 32-tooth MTB cassette on the rear. The chain is
exactly right in all the gears.

If you're still concerned about too short a chain, then pick up either extra Shimano chain pins, or
SRAM power links and add back some links if you think you need them. I would be suprised if
manufacturers purposely install too loose a chain on assembled bikes.

m.f.

[email protected] (TDWFL) wrote in message news:<[email protected]>...
> I'm getting ready to change my first chain ever. I've read the instructions which seem
> straightforward however it seems like if you wrap it around the big-big and add 1 link, when you
> were in the big-big and through the derailer, the derailer would be pointing almost straight
> forward. It seems like no bike I've ever owned was configured this way or maybe that extra 1 link
> adds a lot more slack than I'm thinking it would. Do OEMs size their chains the same or do they
> tend to be on the loose size to allow for different size rear cassettes?
>
> Tim

 

[Harris]

Pete Biggs <pbiggmellon{remove_fruit}[email protected]> wrote:

> A lot of bikes have chains that are longer than necessary. I'm not quite sure why.

I guess because a too short chain is a lot worse than a too long one. Better to err by being a
little on the long side.

> Small-small combos work better with a longer chain - but since small-smalls are not good to use
> anyway, the big-big method normally suffices.

I don't follow that. The chain always appears "long" on the small-small combo.

Art Harris

 

[Pete Biggs]

Harris wrote:

>> A lot of bikes have chains that are longer than necessary. I'm not quite sure why.
>
> I guess because a too short chain is a lot worse than a too long one. Better to err by being a
> little on the long side.

And perhaps to make the big ring + largest sprocket but one work and feel better? Personally I don't
even use that gear (or even the next one+ along).

>> Small-small combos work better with a longer chain - but since small-smalls are not good to use
>> anyway, the big-big method normally suffices.
>
> I don't follow that. The chain always appears "long" on the small-small combo.

I must be wrong there. Thanks for the correction.

~PB