What kind of chainring is this?

What kind of chainring is this, Why are the teeth spaced so wide?

http://cgi.ebay.com/5-pin-49mm-B-C-5...QQcmdZViewItem

-Nate

On Mon, 02 Jan 2006 10:29:51 -0800, Llatikcuf wrote:

What kind of chainring is this, Why are the teeth spaced so wide?

http://cgi.ebay.com/5-pin-49mm-B-C-5...QQcmdZViewItem

It's for old "block" chain, which was 3/16 x 1". Such chains/cogs were
used on the track up to the late '60s (I had one then, and so did maybe
25% of those on the track). They were also used on utility bikes until
probably somewhat later.

Track bikes then went to 1/8x1/2 chain, and now many are going to the
3/32x1/2 that is the standard size for road bikes.

Chains for that chainring are nearly impossible to find any more, and if
you do find it, it would be a roller chain rather than the traditional
block chain, with two rollers fitting between each pair of teeth on the
ring.

See also http://www.sheldonbrown.com/gloss_ba-n.html#block

If I had to guess, I'd say it looked a lot like a TA chainring; at least
the bolt circle looks like what was used on the TA cyclotouriste cranks.

--

David L. Johnson

__o | It is a scientifically proven fact that a mid life crisis can
_`\(,_ | only be cured by something racy and Italian. Bianchis and
(_)/ (_) | Colnagos are a lot cheaper than Maserattis and Ferraris. --
Glenn Davies

On Mon, 02 Jan 2006 13:53:17 -0500, "David L. Johnson"
wrote:

Chains for that chainring are nearly impossible to find any more, and if
you do find it, it would be a roller chain rather than the traditional
block chain, with two rollers fitting between each pair of teeth on the
ring.

IMLE, such sprockets usually work just fine with a conventional 1/2"
single-speed chain, though.
--
Typoes are a feature, not a bug.
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Nate Llatikcuf writes:

What kind of chainring is this? Why are the teeth spaced so widely?

http://tinyurl.com/9affz

It is for an inch pitch chain that came to bicycles in the days when
Renold invented the bicycle chain, before roller chains that are
common in most chains today. Elongated steel blocks with rounded ends
were linked by side plates and pins just as chains are today. These
chains were replaced by roller chains on bicycles, first with 1/8"
wide half inch pitch chains and then with the 3/32" half inch pitch
derailleur chain that today has gotten even narrower so the
mechanical aficionados can have 30 gears.

Meanwhile track bicycles continued to use block chain because many of
them were equipped with inch pitch sprockets. These riders even
eschewed the roller modified inch pitch chains that were common on
every day balloon tired street bicycles. These chains had a pair of
rollers close together that replaced the solid steel block.

http://www.sheldonbrown.com/gloss_ba-n.html
http://www.bikecult.com/works/chainwheel.html

Jobst Brandt

Where's the hatrack writes:

Chains for that chainring are nearly impossible to find any more,
and if you do find it, it would be a roller chain rather than the
traditional block chain, with two rollers fitting between each pair
of teeth on the ring.

IMLE, such sprockets usually work just fine with a conventional 1/2"
single-speed chain, though.

Not true. Don't succumb to MAS (Male Answer Syndrome) when you don't
know. The teeth on inch pitch sprockets are way to big to fit into a
1/2" pitch chain. The pitch would fit but the teeth don't.

Jobst Brandt

On Mon, 02 Jan 2006 19:10:57 GMT, Werehatrack
wrote:

On Mon, 02 Jan 2006 13:53:17 -0500, "David L. Johnson"
wrote:

Chains for that chainring are nearly impossible to find any more, and if
you do find it, it would be a roller chain rather than the traditional
block chain, with two rollers fitting between each pair of teeth on the
ring.

IMLE, such sprockets usually work just fine with a conventional 1/2"
single-speed chain, though.

On further reflection, the ones I've seen that were in use with a
regular chain were made with a different tooth shape; they were
actually just skip-tooth, not block-chain sprockets. The one pictured
is almost certainly for block chain or the inch-pitch roller chain
with irregular spacing that is no longer used on new bikes TTBOMK.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Where's the hatrack writes:

Chains for that chainring are nearly impossible to find any more,
and if you do find it, it would be a roller chain rather than the
traditional block chain, with two rollers fitting between each
pair of teeth on the ring.

IMLE, such sprockets usually work just fine with a conventional
1/2" single-speed chain, though.

On further reflection, the ones I've seen that were in use with a
regular chain were made with a different tooth shape; they were
actually just skip-tooth, not block-chain sprockets. The one
pictured is almost certainly for block chain or the inch-pitch
roller chain with irregular spacing that is no longer used on new
bikes TTBOMK.

Oh? Where do we find such sprockets and how do they look? Are you
sure you saw such a beast? That this is an inch pitch sprocket is
obvious, that it was used with a block chain is not. Most youth
bicycles were equipped with inch pitch adaptation roller chains, the
block chain having vanished from all bicycles except track riders who
swore that only a steel block was strong enough to withstand their
sprinting.

I recall listening to that BS while a friend and great sprinter
converted his bicycle to 3/32" derailleur chain to win many sprints.
The nay sayers warned him that the chain would soon fail. Of course
we know today that MTB's using 20t "chainwheels" put more force on
chains than any track sprinter did.

Jobst Brandt

wrote:
Of course
we know today that MTB's using 20t "chainwheels" put more force on
chains than any track sprinter did.


"gelul"

With a trackbike the largest forces on the chain occur when things go
wrong, ie when the chain climbs a tooth. With a MTB the derailleur cum
chaintensioner will add some slack, on a fixed gear bike something else
will have to give.

--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Jobst Brandt wrote:
Where's the hatrack writes:
...
On further reflection, the ones I've seen that were in use with a
regular chain were made with a different tooth shape; they were
actually just skip-tooth, not block-chain sprockets. The one
pictured is almost certainly for block chain or the inch-pitch
roller chain with irregular spacing that is no longer used on new
bikes TTBOMK.

Oh? Where do we find such sprockets and how do they look? Are you
sure you saw such a beast?...

I saw a mixte frame Kabuki Submariner [1] a few years ago equipped with
a freewheel where the largest cog (equivalent to 36 teeth) only had a
tooth for every third chain link, IIRC. The other cogs and chainrings
appeared conventional, and the chain appeared to be standard 1/2" pitch
and 3/32" width.

[1] Stainless steel tubing with aluminium alloy lugs cast around the
tubing.

--
Tom Sherman - Fox River Valley

Tom Sherman writes:

On further reflection, the ones I've seen that were in use with a
regular chain were made with a different tooth shape; they were
actually just skip-tooth, not block-chain sprockets. The one
pictured is almost certainly for block chain or the inch-pitch
roller chain with irregular spacing that is no longer used on new
bikes TTBOMK.

Oh? Where do we find such sprockets and how do they look? Are you
sure you saw such a beast?...

I saw a mixte frame Kabuki Submariner [1] a few years ago equipped
with a freewheel where the largest cog (equivalent to 36 teeth) only
had a tooth for every third chain link, IIRC. The other cogs and
chainrings appeared conventional, and the chain appeared to be
standard 1/2" pitch and 3/32" width.

That isn't a chainring. Maybe you missed the initial picture and
question which was a bout a steel chainring of old.

[1] Stainless steel tubing with aluminium alloy lugs cast around the
tubing.

I don't get it. What does this have to do with chain pitch?

Jobst Brandt