WHy no red tires on cars - only antique bikes?*

On Feb 7, 4:35*am, wrote:
Dear Martin,

The best rubber for early bicycles (highwheelers) was considered to be
Para rubber (from the Para rubber-tree region of Brazil, as opposed to
African and other sources).

The red color came from the compounds (kmostly antimony) that made the
natural rubber harder and stronger and longer-wearing, but not so
stretchy.

Gray rubber tires were considered inferior, even though they might use
the same Para rubber. Gray rubber was stretchy and wore quickly and
failed more easily because it was mostly natural rubber, plus the
minimum amount of sulphur needed for vulcanizing. Gray rubber simply
lacked the compounds that turned natural Para rubber into better
stuff.

This passage about the gray and red rubber used in inner tubes
explains the basic idea:

"To effect proper vulcanization, only about three per cent of sulphur
is needed. Tubes which are made of red rubber, while stronger, are not
so elastic as as those made of gray rubber. The red color is given to
rubber chiefly by the use of metallic oxids, chiefly antimony. When so
treated, the elongation is about five times its length when not more
than fifty per cent of oxids are used. Gray rubber, which is free from
adulteration, except the necessary sulphur, should stretch to seven
times its length."


Thank you, Carl, for clearing that up. I was thinking of this again
this morning as the sun came up like a red rubber ball.

(And you're correct about Google Books and Canadian - or possibly all
Non-USA-based ISPs) being blocked from the actual contents.)

On Feb 7, 1:59*pm, Martin Krieg wrote:
THX for taking the time to do research for this!! I am going to post it
at the Wheelmen sitehttp://thewheelmen.org/forum/default.asp*where I
have also posed this question.

* *THX 4 U!

In article
,



wrote:
Dear Martin,

The best rubber for early bicycles (highwheelers) was considered to be
Para rubber (from the Para rubber-tree region of Brazil, as opposed to
African and other sources).

The red color came from the compounds (kmostly antimony) that made the
natural rubber harder and stronger and longer-wearing, but not so
stretchy.

Gray rubber tires were considered inferior, even though they might use
the same Para rubber. Gray rubber was stretchy and wore quickly and
failed more easily because it was mostly natural rubber, plus the
minimum amount of sulphur needed for vulcanizing. Gray rubber simply
lacked the compounds that turned natural Para rubber into better
stuff.

This passage about the gray and red rubber used in inner tubes
explains the basic idea:

"To effect proper vulcanization, only about three per cent of sulphur
is needed. Tubes which are made of red rubber, while stronger, are not
so elastic as as those made of gray rubber. The red color is given to
rubber chiefly by the use of metallic oxids, chiefly antimony. When so
treated, the elongation is about five times its length when not more
than fifty per cent of oxids are used. Gray rubber, which is free from
adulteration, except the necessary sulphur, should stretch to seven
times its length."

*http://books.google.com/books?id=HKI...frontcover#PPA...
orhttp://tinyurl.com/32q5cr

Canandian posters may have limited or no access to Google books.

Elsewhere, the book gives examples of gray stretchy inner tubes being
made of 94% natural Para rubber and 6% sulphur (hardly any compounds),
while red inner tubes, longer lasting, were only about 75% rubber and
25% antimony, magnesia, and so on (four times as much non-rubber
compound).

Tires were harder and used even less rubber than inner tubes, but the
same principles held. Red rubber meant lots of antimony and other
stuff to improve the soft, too-stretchy natural rubber, while gray
rubber meant the bare minimum of improving chemicals.

Improvements in technology led to the use of carbon black to make the
natural rubber last longer and still provide good traction, followed
by the rise of synthetic rubber.

Here's an example of an 1887 highwheeler ad that boasts of tires made
of the "very best quality red Para rubber", as opposed to the inferior
gray stuff:
*http://www.tallbike.com/tall/87rudge.html

Note that the huge online book about tires is discussing early car
tires and inner tubes.

Cheers,

Carl Fogel

Dear Martin,

Everything that you ever wanted to know about making rubber bicycle
tires, in popular form:

http://books.google.com/books?id=rZD...#PRA1-PA381,M1

or http://tinyurl.com/yqmmt7

Alas, the McClure's magazine pages can be beastly slow to load and may
not be available to non-U.S. posters.

The article is from McClure's Magazine volume 8, 1896-1897 November-
April, page 381, "A Visit to the Hartford Rubber Works," Cleveland
Moffett.

Cheers,

Carl Fogel

On Feb 7, 1:59*pm, Martin Krieg wrote:
THX for taking the time to do research for this!! I am going to post it
at the Wheelmen sitehttp://thewheelmen.org/forum/default.asp*where I
have also posed this question.

* *THX 4 U!

Dear Martin,

Here's a really short, clear explanation, from the English Mechanic of
1878:

"Get the best quality rubber. The grey is in reality the purer of the
two [red and grey], but the red is rather more durable on account of a
mixture of a hardening nature, sulphur being the principal ingredient.
Therefore, have the red, or, as it is called, 'indestructible'."

"The weight will be about 4 lb. The better the rubber, the lighter--
consequently, there is not much gained by buying the lower quality."

http://books.google.com/books?id=Unk...rr=0#PPA144,M1

Actually, both grey and red rubber used sulphur for vulcanizing, and
the red color and durability was from antimony and other added
ingredients, but the advice was basically good.

Cheers,

Carl Fogel