Chain Length

On 20 Aug 2003 15:14:30 -0700, Chris Atkinson <[email protected]> wrote:

> This may be a stupid question, if so then sorry. I am looking for a chain for my 12-speed bike but
> I can only find chains that say 8, 9, or 10 speed chain. Does the 8,9, 10 refer to the number of
> rear sprockets? If not, what do I need?
>
> Thanks, Chris
>

Yes, it does. If you have 9 rear sprockets, you "need" a 9-speed chain. Are you going to put it on?
If so, there's a technique for determining how many links to keep. Basically, wrap the chain around
the large chainring and the large rear sprocket, then through the rear derailleur (sp?). Overlap the
chain and keep two extra links. Toss the rest (well, don't toss them -- keep them in your bag in the
unlikely event that you break a chaing).

--
Bob M in CT Remove 'x.' to reply

Chris Atkinson writes:

> I am looking for a chain for my 12-speed bike but I can only find chains that say 8, 9, or 10
> speed chain. Does the 8,9, 10 refer to the number of rear sprockets? If not, what do I need?

You are looking in the wrong store. Go to a bicycle shop and ask for a new derailleur chain. I don't
know of any good chains that are labeled as you say.

Chain length is determined by the largest sprocket front and rear that the chain must engage. You
can determine this by engaging a new chain with these sprockets and seeing how many links overlap
when the derailleur idler cage is in its mid position of chain tensioning. After making that
determination try the same length on the smallest pair, front to rear that you will engage and see
that there is still travel in the derailleur idler cage... still produces chain tension.

Much easier than that is to get a new chain from your bike shop and shorten it to the length of your
old chain that must have worked. Do this by laying the two chains side by side (on their flat sides)
and rune them between your fingers, one nested in the other's chain links, from one end to the
other. This is o take care of the wear in the old chain that is longer than it is when it was new
due to wear.

Jobst Brandt [email protected] Palo Alto CA

On Wed, 20 Aug 2003 22:40:26 GMT, Bob M <[email protected]> wrote:

>On 20 Aug 2003 15:14:30 -0700, Chris Atkinson <[email protected]> wrote:
>
>> This may be a stupid question, if so then sorry. I am looking for a chain for my 12-speed bike
>> but I can only find chains that say 8, 9, or 10 speed chain. Does the 8,9, 10 refer to the number
>> of rear sprockets? If not, what do I need?
>>
>> Thanks, Chris
>>
>
>Yes, it does. If you have 9 rear sprockets, you "need" a 9-speed chain. Are you going to put it on?
>If so, there's a technique for determining how many links to keep. Basically, wrap the chain around
>the large chainring and the large rear sprocket, then through the rear derailleur (sp?).

I have always seen this method WITHOUT going through the rear derailleur.

>Overlap the chain and keep two extra links. Toss the rest (well, don't toss them -- keep them in
>your bag in the unlikely event that you break a chaing).

On 20 Aug 2003 15:14:30 -0700, [email protected] (Chris Atkinson) wrote:

>This may be a stupid question, if so then sorry. I am looking for a chain for my 12-speed bike but
>I can only find chains that say 8, 9, or 10 speed chain. Does the 8,9, 10 refer to the number of
>rear sprockets? If not, what do I need?
>
>Thanks, Chris

You need an '8-speed' chain. SRAM PC-58, for example.

The basic width and dimensions of chains didn't change as they moved from 6 to 7 to 8 speeds. The
change occurred in the gears and the rear hubs. But when they went to 9 and 10 speeds, they had to
modify the chain dimensions to make it smaller (in width only, I believe) because they are now
shoving extra gears into the same space.

A great site for check out all sorts of weird bike things-

http://www.sheldonbrown.com/harris/#articles

http://www.sheldonbrown.com/glossary-c.html

On Wed, 20 Aug 2003 22:40:26 GMT, Bob M <[email protected]> wrote:

> On 20 Aug 2003 15:14:30 -0700, Chris Atkinson <[email protected]> wrote:
>
>> This may be a stupid question, if so then sorry. I am looking for a chain for my 12-speed bike
>> but I can only find chains that say 8, 9, or 10 speed chain. Does the 8,9, 10 refer to the number
>> of rear sprockets? If not, what do I need?
>>
>> Thanks, Chris
>>
>
> Yes, it does. If you have 9 rear sprockets, you "need" a 9-speed chain. Are you going to put it
> on? If so, there's a technique for determining how many links to keep. Basically, wrap the chain
> around the large chainring and the large rear sprocket, then through the rear derailleur (sp?).
> Overlap the chain and keep two extra links. Toss the rest (well, don't toss them -- keep them in
> your bag in the unlikely event that you break a chaing).
>

Oops. I forgot to say that you can use an 8 speed or lower chain.

--
Bob M in CT Remove 'x.' to reply

catharus <[email protected]> spake thusly on or about Wed, 20 Aug 2003
23:03:33 UTC

-> You need an '8-speed' chain. SRAM PC-58, for example. ->

actually the PC-10 are made for the 5-7 cog clusters and the 58 would be worth as much as the bike
in all likelyhood
--
I hurt before the ride so fibro gives me a head start on the rest of the pack. silver lining?
[email protected]

On Wed, 20 Aug 2003 22:58:00 GMT, <[email protected]> wrote:
> Chris Atkinson writes:
>> I am looking for a chain for my 12-speed bike but I can only find chains that say 8, 9, or 10
>> speed chain. Does the 8,9, 10 refer to the number of rear sprockets? If not, what do I need?
>
> You are looking in the wrong store. Go to a bicycle shop and ask for a new derailleur chain. I
> don't know of any good chains that are labeled as you say.

I thought that 9 speed chains are narrower than, for example, 7 speed chains.

Granted, the width of the chain has nothing to do with the length.

Also, I concur, visit a LBS (local bicycle shop), bring the bike, and ask for the proper chain. They
will likely have it, and for a small fee they should shorten it to the correct length for you, so
you just have to put it on.

Ask for a special tool-free link, if it doesn't come with one (all the chains at my LBS come with
one), so you can put the chain ends together without a chain tool...or just pay them to put it on,
too. It's not hard to do yourself, though.

> Jobst Brandt [email protected] Palo Alto CA
--
Rick Onanian

Bran wrote:

> catharus <[email protected]> spake thusly on or about Wed, 20 Aug 2003
> 23:03:33 UTC
>
> -> You need an '8-speed' chain. SRAM PC-58, for example. ->
>
> actually the PC-10 are made for the 5-7 cog clusters and the 58 would be worth as much as the bike
> in all likelyhood
> --
> I hurt before the ride so fibro gives me a head start on the rest of the pack. silver lining?
> [email protected]

everone likes shiney things. charles

Thanks for the input everyone!

I think asking at my LBS is probably the best idea since people who know what they are talking about
can actually see my bike and tell me what I need. I am a graduate student on a very limited income,
(and also like getting my hands dirty) so I think I will bypass the fee and do it myself. I have
looked at Sheldon Brown's site, and it does not seem too hard to appropriately size the chain.

The reason I am considering a new chain is due to the chain streching measurements suggested by
Sheldon Brown. I measure exactly 1/16" over, which according to him, means I should get a new chain.

Nesting further into my reasoning, I was looking at chain info because I just got an older Schwinn
world sport I am having some problems with the one of the rear (i don't know if this is the proper
term) sprockets. When I pedal in this sprocket, the chain jumps ahead. Upon more consideration, I
realized that since it is only one sprocket in which the problem occurs, the offending equipment is
probably in the sprocket, not the chain.

I am sure one of you more experienced cyclists have experience with this problem and could advise me
on what the problem could be and possibly how to fix it. If it is an expensive fix, then I will say
"screw it" as I don't mind having a 10-speed as opposed to a 12-speed.

Thanks, Chris

On Thu, 21 Aug 2003 14:47:01 +0000, Chris Atkinson wrote:

> Nesting further into my reasoning, I was looking at chain info because I just got an older Schwinn
> world sport I am having some problems with the one of the rear (i don't know if this is the proper
> term) sprockets. When I pedal in this sprocket, the chain jumps ahead. Upon more consideration, I
> realized that since it is only one sprocket in which the problem occurs, the offending equipment
> is probably in the sprocket, not the chain.

This is typical when a new chain is used on a worn-out sprocket. But the worn sprocket (others may
be nearly as bad) will quickly wear out the new chain, so if the chain shows the wear you mention,
it should also be replaced.

--

David L. Johnson

__o | Arguing with an engineer is like mud wrestling with a pig... You _`\(,_ | soon find out the
pig likes it! (_)/ (_) |