Tire-making: musings on carbon black and the myth of (some) radials.....
 

Recently I got around to obtaining two different samples of carbon black
to try adding to the latex rubber I was using. I had read multiple
sources that carbon black was added as it increased the strength of the
rubber considerably. It didn't change anything other than the color.

Looking online I found that carbon black only increases the strength of
synthetic rubber, and can only increase some of its properties up to
about-equal to natural latex-

http://en.wikipedia.org/wiki/Carbon_..._carbon_blacks

I had also read somewhere that usually when you see a white rubber tire,
it is probably made of mostly latex. Styrene-butadiene rubber begins
white, but isn't strong enough for much without adding an extender. The
best extender for it is carbon black, but that also colors the rubber
black at the same time.

There is still another reason to add carbon to latex, in that the carbon
helps the rubber to resist UV damage.

----------

All this got me to wondering which tires were non-black.

I recall that some of the infamous Shell Eco-Marathon Michelin tires
were radials, and they were light blue.... So I went looking for more
info on them.

And it is now that NO noticed,,,, that they're not radials. At least,
not all of them.

This page for the Americas region:
http://www.shell.com/home/content/ec...aqs/technical/
has links to photos of them. If you zoom in to both pics, you can easily
see diagonal cords coming off the beads of inside both tires.
Prototype tires-
http://www-static.shell.com/static/e...pe_Tire_LR.jpg
Urban Concept tires-
http://www-static.shell.com/static/e...eline_tire.jpg

There is also two PDFs of 'tire specifications' but these only give the
sizing and the necessary rim dimensions, neither says anything about the
tire's construction.

,,,,,,,,

On this page:
http://www.bikeforums.net/archive/in...p/t-89497.html
is someone asking where they can get "eco marathon radials" and someone
else claiming that these tires are only sold to the EUROPEAN event....
?????
Something smells rotten in Denmark if this is supposed to be a "world
championship" yet the best tires are only available to the Euro teams.

But I don't even know if the Euro tires are radials.
I looked for a while and I could not find any photo of any Michelin Eco
Marathon tire that appeared to be a radial, either from recent or past
years. And yet everybody says they are? Except Shell?

Shell doesn't have the rules of past years online, I suppose to avoid
confusion.
I got to the Americas rules FAQ page by this address-
http://www.shell.com/home/content/ec...l/#subtitle_10
but when I changed 'americas' to 'europe' to try to see the European
rules (reflecting the change they use in other pages) it gives me a 404
page. If you are in Europe, can you reach a different rules FAQ page,
and does it show or state that different tires are sold there?

Does anyone have any first-hand knowledge of this event?
Were these tires ever radials?
I have seen that in the last few years there are a lot of teams using
regular bicycle tires; assuming that the Michelin tires sold by Shell
are just normal tires then there's hardly any reason to pay $40 for them.

Tire-making: musings on carbon black and the myth of (some) radials.....
 

On Jul 26, 2:35*pm, Doug Cimperman wrote:
Recently I got around to obtaining two different samples of carbon black
to try adding to the latex rubber I was using. I had read multiple
sources that carbon black was added as it increased the strength of the
rubber considerably. It didn't change anything other than the color.

I think you find that carbon filler provides shear stiffness (and
hysteresis loss) in thicker treads. "white strips" which would be
used for record breaking pursuit riding were simply painted on latex
and had sufficient tread stability in their thin form, which was all
that was required to last the event.


Looking online I found that carbon black only increases the strength of
synthetic rubber, and can only increase some of its properties up to
about-equal to natural latex-

http://en.wikipedia.org/wiki/Carbon_..._carbon_blacks

I had also read somewhere that usually when you see a white rubber tire,
it is probably made of mostly latex. Styrene-butadiene rubber begins
white, but isn't strong enough for much without adding an extender. The
best extender for it is carbon black, but that also colors the rubber
black at the same time.

There is still another reason to add carbon to latex, in that the carbon
helps the rubber to resist UV damage.

----------

All this got me to wondering which tires were non-black.

I recall that some of the infamous Shell Eco-Marathon Michelin tires
were radials, and they were light blue.... So I went looking for more
info on them.

And it is now that NO noticed,,,, that they're not radials. At least,
not all of them.

This page for the Americas region:http://www.shell.com/home/content/ec...cipants/region...
has links to photos of them. If you zoom in to both pics, you can easily
see diagonal cords coming off the beads of inside both tires.
Prototype tires-http://www-static.shell.com/static/ecomarathon/downloads/2011/america...
Urban Concept tires-http://www-static.shell.com/static/ecomarathon/downloads/2012/america...

There is also two PDFs of 'tire specifications' but these only give the
sizing and the necessary rim dimensions, neither says anything about the
tire's construction.

,,,,,,,,

On this page:http://www.bikeforums.net/archive/in...p/t-89497.html
is someone asking where they can get "eco marathon radials" and someone
else claiming that these tires are only sold to the EUROPEAN event....
?????
Something smells rotten in Denmark if this is supposed to be a "world
championship" yet the best tires are only available to the Euro teams.

But I don't even know if the Euro tires are radials.
I looked for a while and I could not find any photo of any Michelin Eco
Marathon tire that appeared to be a radial, either from recent or past
years. And yet everybody says they are? Except Shell?

Shell doesn't have the rules of past years online, I suppose to avoid
confusion.
I got to the Americas rules FAQ page by this address-http://www.shell.com/home/content/ecomarathon/for_participants/region...
but when I changed 'americas' to 'europe' to try to see the European
rules (reflecting the change they use in other pages) it gives me a 404
page. If you are in Europe, can you reach a different rules FAQ page,
and does it show or state that different tires are sold there?

Does anyone have any first-hand knowledge of this event?
Were these tires ever radials?
I have seen that in the last few years there are a lot of teams using
regular bicycle tires; assuming that the Michelin tires sold by Shell
are just normal tires then there's hardly any reason to pay $40 for them.