5 replies to this topic

[prseagerthomas]

Two questions in one thread.

 

Both Mercedes-Benz and Auto Union seem to have used related wheels, but then weren't most wire wheels related?

 

Bearing in mind the great efforts by Germany in the Silver Arrows period to  avoid imports (and thus avoid having to send German Reichsmarks abroad), it seems likely that the wheels in question were of German origin. The only manufacturer of the period I have been able to come up with is Fabrik Hering.

 

Any answers/comments appreciated.

 

White tyres, related to my earlier Delage thread. many vintage and Edwardian cars seem to have had either white tyres, or white painted tyres. Guesses/opinions as to why this was again appreciated. The only idea I have so far is that it was an effort to reflect the heat of the sun, perhaps worthwhile at a period when tyres really did not last long.

 

Peter.

[Vitesse2]

 

Natural rubber needed some kind of additive for wear resistance and structural strength. Zinc oxide ( yes the stuff that gets put on noses as sunscreen) was used and it made the tires almost white, really still a bit off white gray light tan. Iron ozide ( rust) was used too and those tires and tubes are dark pinkish red. Next came carbon, it is still used because it worked well and was the cheapest. In old time black and white pictures the red tires can be mistaken for white or black. There were many color combinations, black tires with red walls for instance!

Source: http://forums.aaca.o...ite-300480.html

 

IIRC this is also covered in some detail in a book by Eric Tompkins called 'The history of the pneumatic tyre' (Eastland Press/Dunlop Archive). I borrowed it from the library a few months ago, but that wasn't really the focus of what I was looking for. There are two very cheap copies on ABE at the time of writing.

[D-Type]

I always thought that adding lampblack (carbon) to the rubber was to provide a screen to protect the rubber from degradation under ultra-violet light.  Well, you live and learn.

[Lee Nicolle]

A little off topic but white tyres are used on Gophers, wheel chairs etc because they do not leave marks. But they do perish quite badly.
I have just fitted a set of tyres on a Gopher!! Quite expensive for little tyres.

[austmcreg]

A little off topic but white tyres are used on Gophers, wheel chairs etc because they do not leave marks. But they do perish quite badly.
I have just fitted a set of tyres on a Gopher!! Quite expensive for little tyres.

From someone who works in the rubber industry; carbon black is what gives the rubber its mechanical properties related to wear resistance, hardness and strength. Very simplistically, more carbon black = harder and stronger. Natural rubber (from the tree) is a yellowish, opaque colour, and the various synthetic polymers which are blended with natural rubber are mostly opaque (varying colours) as well. What we call coloured rubber (ie non-black ) is obtained by adding pigments or coloured fillers (such as zinc oxide for white). These are more expensive, generally, than carbon black, Coloured rubber requires very clean mixers etc to avoid contamination by black, and so either needs dedicatedeqipment or an expensive cleanup before production. Thus non-black rubber tends to be quite expensive.

 

Perversely, because carbon black is cheaper than the natural rubber or the synthetic polymers, the more strength / hardness you add to the rubber with increasing carbon black, the cheaper it gets (by the kg).

 

Some early motorcycle tyres were white, and can be bought as reproductions. In my experience they are good for display only and should not see a road. They will not last long on a warm day or if subjected to any high loads. Yes, white or grey (with very small quantities of carbon black) are used in non-marking tyres. Gophers and wheel chairs do not subject the tyres to any loads that would be a problem (though I suspect the competition type wheelchairs might use something better).

 

The reason some early tyres were non-black? I dont know for sure but I suspect, because carbon black is a by-product of the oil refining process, in veteran & Edwardian times it was probably either difficult to obtain, very expensive, or both.

 

 

Rob Saward

Edited by austmcreg, 24 December 2013 - 05:43.

[ray b]

 

 

Perversely, because carbon black is cheaper than the natural rubber or the synthetic polymers, the more strength / hardness you add to the rubber with increasing carbon black, the cheaper it gets (by the kg).

 

 

 

The reason some early tyres were non-black? I dont know for sure but I suspect, because carbon black is a by-product of the oil refining process, in veteran & Edwardian times it was probably either difficult to obtain, very expensive, or both.

 

 

Rob Saward

 I wonder if carbon nano tubes would be a trick

 

would coal soot work in stead of pure oil carbon

the ED's should have had alot of that