Pitch

On Wed, 25 Feb 2004 17:35:55 -0000, "Neil Smith" <[email hidden]>

Quoted message said:

Need new rings, how do you measure the pitch on a chainset? Thanks

how old is the bike?

Neil Smith said:

Need new rings, how do you measure the pitch on a chainset?

Sheldon Brown has a conversion table. You measure distance between adjacent bolts, the table gives
you bolt circle diameter:

sheldonbrown.comgloss bo z.htmlOpen ↗
--
terry morse Palo Alto, CA terrymorse.combikeOpen ↗

On Wed, 25 Feb 2004 10:00:08 -0800, Terry Morse <[email hidden]>

Quoted message said:

Neil Smith said:

Need new rings, how do you measure the pitch on a chainset?

Sheldon Brown has a conversion table. You measure distance between adjacent bolts, the table gives
you bolt circle diameter:

sheldonbrown.comgloss bo z.htmlOpen ↗

ah! I thought he was talking about the pitch of the chain! Aren't all chains (at least in the last,
er, 40 years?) the same pitch (length of links)?

thanks
"Terry Morse" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Neil Smith said:

Need new rings, how do you measure the pitch on a chainset?

Sheldon Brown has a conversion table. You measure distance between adjacent bolts, the table gives
you bolt circle diameter:

sheldonbrown.comgloss bo z.htmlOpen ↗
--
terry morse Palo Alto, CA terrymorse.combikeOpen ↗

Neil Smith said:

Need new rings, how do you measure the pitch on a chainset?

Chain pitch is simply the distance between adjacent pins in the chain. All modern bikes use 1/2"
pitch; a few antiques use special 1" pitch chain that is not interchangeable with 1" pitch
industrial chain.

Any rings that you can buy off the shelf will be 1/2" pitch. They are distinguished only by their
tooth width, with single-speed equipment traditionally using 1/8" width and derailleur bikes using
3/32" width. Industrial 1/2" pitch chain is designed for 1/4" wide teeth.

Chalo Colina

Thanks for the informative reply. The bike shop having trouble selecting
replacement rings for my chainset and they were talking "Pitch". How do you
establish which type of ring is required for a particular chain ring. The
old one, I suspect very old is Suigino Comp super-shifter. Would anyone how
to find the size by which I could find something similar? Also I am thinking
of going for a larger large ring, moving up from 48 to 50 or 52. What will
be the sizes for the other two rings. I believe that I will have to adjust
the front derailleur. How to I determine, apart from the hard way, the
correct position?
Thanks
"Chalo" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Neil Smith said:

Need new rings, how do you measure the pitch on a chainset?

Chain pitch is simply the distance between adjacent pins in the chain. All modern bikes use 1/2"
pitch; a few antiques use special 1" pitch chain that is not interchangeable with 1" pitch
industrial chain.

Any rings that you can buy off the shelf will be 1/2" pitch. They are distinguished only by their
tooth width, with single-speed equipment traditionally using 1/8" width and derailleur bikes using
3/32" width. Industrial 1/2" pitch chain is designed for 1/4" wide teeth.

Chalo Colina

Neil Smith said:

How do you establish which type of ring is required for a particular chain ring. The old one, I
suspect very old is Suigino Comp super-shifter. Would anyone how to find the size by which I could
find something similar?

You're going to have to clarify what you mean by "ring" in the first instance.

Quoted message said:

Also I am thinking of going for a larger large ring, moving up from 48 to 50 or 52. What will be
the sizes for the other two rings.

You can probably make a change of 2-4 teeth on the big ring without replacing the other rings. If
you intend to replace them anyway, the best thing to do from a front derailleur standpoint is to
maintain the same intervals between rings, e.g 28-38-48 -> 30-40-50 or 32-42-52. However, I have
never had a problem using a larger big ring, and the ratio between a 28 and a 38 is the same as
between a 38 and a 52. I think it's nice to have the same size step between successive rings.

Quoted message said:

I believe that I will have to adjust the front derailleur. How to I determine, apart from the hard
way, the correct position?

Yes, you'll have to move it upwards along the seat tube to clear the larger ring. Detach the cable
first. With an older front derailleur that has a mostly flat outer cage, just set the derailleur so
that the outer plate is parallel to the big ring, and so that it clears the teeth on the big ring by
about 1.5mm when it is swung through its motion. Verify that your limit stops are set appropriately,
and reattach the cable.

Chalo Colina

The're all the same: 1/2 inch pitch. It's one of the few things on a bicycle that stubbornly refuses
to go metric. Why they can't change it to, say 12 mm, I don't know.

"May you have the wind at your back. And a really low gear for the hills!"

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner geocities.comczcornerOpen ↗