Consider the lowly Chain

In "]news:[email hidden],
[email hidden] <[email hidden]> typed:

Quoted message said:

I was just sitting on the toilet thinking, ok so this isn't the most inspiring thought I've had,
about the bike chain. Now if you measure it, it is supposed to be exactly 12 inches from pin to
pin. If it is more than that your chain has stretched some.

As far as I know this is true of all bike chains. So here's the poser: Why is it 12 inches and not
in milmeters or centimeters? Is this some kind of carry over of the English measuring system and
bikes? Screws and bolts on bikes are in milimeters and I think chain width is in mm's.

Chain and gear pitch is in inches. Or half-inches if you prefer.

Seat tube is in mm but the steerer tube is in inches.

Hub width is in mm but wheel diameter is in inches.

Road frames are in mm but mtb frames are in inches.

Did I leave anything out?

Mike

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

Quoted message said:

I was just sitting on the toilet thinking, ok so this isn't the most inspiring thought I've had,
about the bike chain. Now if you measure it, it is supposed to be exactly 12 inches from pin to
pin. If it is more than that your chain has stretched some.

As far as I know this is true of all bike chains. So here's the poser: Why is it 12 inches and not
in milmeters or centimeters? Is this some kind of carry over of the English measuring system and
bikes? Screws and bolts on bikes are in milimeters and I think chain width is in mm's.

Would you prefer to call it 305 mm?

Pete

Quoted message said:

I was just sitting on the toilet thinking, ok so this isn't the most inspiring thought I've had,
about the bike chain. Now if you measure it, it is supposed to be exactly 12 inches from pin to
pin. If it is more than that your chain has stretched some.

As far as I know this is true of all bike chains. So here's the poser: Why is it 12 inches and not
in milmeters or centimeters? Is this some kind of carry over of the English measuring system and
bikes? Screws and bolts on bikes are in milimeters and I think chain width is in mm's.

Consider this:

www-personal.monash.edu.auQuotes.htmlOpen ↗

Start reading the third paragraph, the one that begins: "The US standard railroad gauge..."

--
Westie (Replace 'invalid' with 'yahoo' when replying.)

"Michael Dart" <[email hidden]> wrote in message news:<[email hidden]>...+

<list of non metric sizes>.

Quoted message said:

Did I leave anything out?

Pedal/crank threads are inches.

MTB handlebars are 1" diameter at the clamp (anything that is 25.4 mm probably traces back to a 1"
standard).

Loose bearings are in inches.

Dave D.

Westie said:

Consider this:

www-personal.monash.edu.auQuotes.htmlOpen ↗

Start reading the third paragraph, the one that begins: "The US standard railroad gauge..."

So this all goes back to the old Ox Cart, wagon rut thing.

Quoted message said:

Westie said:

Consider this:

www-personal.monash.edu.auQuotes.htmlOpen ↗

Start reading the third paragraph, the one that begins: "The US standard railroad gauge..."

So this all goes back to the old Ox Cart, wagon rut thing.

Yep. It appears that the decisive measurement of whether or not your chain is stretched is the
result of how wide a two thousand year old horse's [censored] was....
--
Westie (Replace 'invalid' with 'yahoo' when replying.)