Chain length... old chestnut

Is there general agreement that when replacing chain the method of placing
chain around largest rear cassette cog and largest chainring PLUS 2
links(WITHOUT routing the chain through the derailleur) is good procedure?
Also... my ratios are 12/21 at rear (8 speed) + 42/52 at front - I have
acquired a new spare pair of chainrings although the outer chainring is up a
tooth on my old one - now 53. I guess this will mean at least one additional
chain link to previous or is it small enough an increase in teeth not to
matter?

On Mon, 09 Jan 2006 14:26:18 +0000, Deep Thought wrote:

Is there general agreement that when replacing chain the method of placing
chain around largest rear cassette cog and largest chainring PLUS 2
links(WITHOUT routing the chain through the derailleur) is good procedure?

Should work. The fundamental is that you need to be able to get the chain
on and off of that big-big combo, even though you should not use that
combination. Anything shorter could be disastrous, anything longer makes
shifting sloppier. I always set the length with the chain through the
derailleur, but that hardly matters.

acquired a new spare pair of chainrings although the outer chainring is
up a tooth on my old one - now 53. I guess this will mean at least one
additional chain link to previous or is it small enough an increase in
teeth not to matter?

Probably won't matter. You only added 1/4 link more distance for the
chain to go around -- only half the number of extra teeth since the chain
only touches half the chainring, and it's two teeth per link.

--

David L. Johnson

__o | Deserves death! I daresay he does. Many that live deserve
_`\(,_ | death. And some that die deserve life. Can you give it to
(_)/ (_) | them? Then do not be too eager to deal out death in judgement.
-- J. R. R. Tolkein