Maybe esotheric question but... I was asking me about the rubber use for tyres during WW1 and later. Most cars seems to use natural rubber with a light grey or event white color, but looking at the New Osprey about the armoured vehicle of the red army during the russian civil war most of the tyres seems to be on a very dark color event not black. Was there any synthetic rubber at that time?
As some one who worked at Dunlop for a time I know somethings about tyres and rubber.
First, many tyres (almost all today) contain more than one type of rubber, for example the rubber in the side of the tyre will be different from the tread. Tyres may contain botn synthetic and natural rubber. No tyre contains real 'natural' rubber it has to go through a number of processes.
Secondly, black or grey is not the natural colour of rubber. The black in tyres is there because various substances have been added to the rubber when it is being mixed. This is usually a form of carbon akin to lamp black or soot. It is not there just for cosmetic reasons. Rubber can deteriorate under UV (ie sunlight) and this protects against this. Consequently differences in the colour of rubber tyres could merely reflect different abounts or qualities of 'blacking' added to the rubber mix. I once worked on adding computer controls to Dunlop's Manchester factory where the basic rubber 'crumb' was made to supply both Dunlop factories and other rubber goods manufacturers. - every surface everywhere in the plant was coated in black fine carbon dust ( a major problem when trying to introduce sensetive electronic equipment). The factory was the original Mackintosh works and rubber had been mixed there since long before WW1, the basic process had not changed. The mix of ingredients the length of time for which it is agitated and heated and the temperature can all have major effects on the quality of rubber (so you could produce a batch of very soft rubber and later a batch of ebonite (which sets harder than bakelite and was used before plastics became generally available). The dark rubber might just be the result of using more carbon in the mix or a substitute material.
Thirdly, whilst there was little use of synthetic rubber in WW1 as in Britain , the US etc The Central powers were experimenting with various ersatz rubbers (and often producing some very unsatisfactory resulys) using coal as a basic raw material.
Earlier tyres might have had less 'blacking' in the mix. However when my late father was restoring a WW1 War Department Douglas motor cycle the old tyres were very perished but blackish. When replacement tyre were acquired (theoriginal moulds were still in use !) the newly moulded tyres looked much the same.
Before carbon black was used in tires, they used zinc oxide, which is white, for the same purpose. The Goodyear company website give 1915 as they date when they switched from zinc oxide to carbon black, but other companies may have changed over at different times. So those early tires may well have been white when they came out of the factory, though exposure to the grime of everyday use may well have darkenned them.
I think that Goodyear may have been one of the last to switch - Dunlop appear to have been using carbon black before ww1. Given that all zinc products were scarce resources in wartime in the Central Powers one would think that if blacking was not used at the start of WW1 it soon would be.
I've seen dates as early as 1906 for the first use of carbon black in a tire, but you can see in photos that at least some of the vehicles in WWI are clearly not running black tires, but some very light colour would seem to suggest that zinc oxide based tures were still being used through most, if not all of the Great Wa, thugh this certainly may not have been universal. I imagine further research could shed some light on this.
The enclosed WW1 colour phot shows a French vehicle with whitish front tyres although the rear ones are greyer. Note however that the tread is slightly darker in both cases. I've seen this effect on some colorised photos and possibly monochrome, some times the contrast being greater. I don't think that it is purely dirt or fashionable white wall but more likely that the tread is a different quality rubber (as is normal in most tyre technology). Doing a first pass through my photo files suggests that lighter tyres are more likely earlier in the war but there is no hard and fast rule. Much I suspect depends on which company made the tyres and how old the stocks were. I also suspect that less carbon black was used in the mix in the early days when it was employed so these tyres would tend to be a light grey.
BTW slightly off topic, did you know that the Gestapo specified Dunlop tyres as standard fit for all their vehicles? They were especially fond of Dunlop white walls. This was an aspect of Dunlop history that was not particualry emphasised by the company.
Some more clarification Zinc Oxide is NOT used for the same purpose as carbon black. Zinc Oxide is used to assist in the vulcanisation process whereas carbon black is used both as a protection against UV and as a means of increasing the resistance of the rubber to wear. Tyres today contain BOTH materials. This would make sense of some tyres I have seen in WW1 photos that have a very light side but a darker tread, carbon black may well have been added to the rubber in the tread to reduce wear. Looking again at photos tyres range in shades from what looks like a creamy white through various shades of grey from quite light to very dark. Itis not ususual to find vehicles with different coloured tyres, for examply whitish front tyres and dark rear ones or the reverse. I've a shot of a British military car with grey tyres on the wheels and a whitish spare tyre. American trucks can be seen some with light tyres others dark. A colour photo of a preserved WW1 truck has tyres that are a light brown!
I would suspect that it all depends on where the tyres came from. As a vehicle could be retyred many times in its service the colours of its tyres could change over its history. For the modeller the safest thing would be to try an find a photo of the particular vehical. Failing that I would suspect that light grey is a prety safe bet in that probably at least one vehicle of the type probably had light grey tyres at some time in its history.
The best tyres of IWW was Russian, from "Prowodnik" (Riga) - 2nd greatest manufacturer of rubber and tyres worldwide! The best tyres of the world was "Prowodnik-Columb"!!!
Also was good russian "Gussmatic" (no pneu-tyres) with chemie fouled, special maked for armoures cars.
