Not realy sure whether they are silicon based but unlike true silis you can true ortmans The grip is superb on plastic and they need no added traction aids ,the only down side seems to be that they leave a fine powdery deposit after prolonged use rendering other tyres useless ,we discovered at wrexham on sunday after the audi race that proslot ninco and even ppr tyres wouldnt grip properly ,Any one else had similar problems?
I have worked with silicon and resin for over 12 years as part of my own business. These tyres are not silicon though they have some content of silicon and lower grade silicon usualy contains chalk as a filler (for cost saving). If they do contain resin you should be very careful indeed as the dust from resins is very dangerous. When working with resin you should always wear a respirator, not a dust mask.
In terms of what they do to your track...the technical term would be that they knacker it!
There should be NO resins in a tire. I don't see why they would use a resin anyway. And, as Jonny says, nasty stuff when released as a dust.
Silicones usually only dust when they are made from low-grade, contaminated material. High-grade silicones, once cured, will wear so gradually and so finely that they leave no visible trace, except perhaps for a darkening of the surface they are running on - but they should NOT "powder" or "dust".
If these tires are a silicone and rubber combination, it may be some additive they have used to facilitate the mix of the two materials, or perhaps even a catalyst.
Simply put, Polysiloxane, (the proper name for Silicones), are stable synthetic compounds (polymers), with lubricating properties that mimic organic, carbon based compounds, such as petroleum, animal fats and vegetable oil.
Silicone is a term much like "plastic" - it covers a rather wide range of materials and properties. The chemistry of a particular polymer determines its characteristics, from hard and brittle varnishes, to soft and flexible rubbers. The initial work on polysiloxane chemistry dates back almost 60 years and it continues today.
Silicones are used for a lot of things. They can be elastomers and lubricating oils. The caulking in your bathroom is probably made of a silicone. Among other things, silicones are also used to make the heat resistant tiles on the bottom of the space shuttle, breast and other implants, and hair conditioners that don't cause buildup.
Dictionary.com defines Silicone as:
" 1) Any of a group of semi-inorganic polymers based on the structural unit R2SiO, where R is an organic group, characterized by wide-range thermal stability, high lubricity, extreme water repellence, and physiological inertness and used in adhesives, lubricants, protective coatings, paints, electrical insulation, synthetic rubber, and prosthetic replacements for body parts."
" 2) Any of a large class of siloxanes that are unusually stable over a wide range of temperatures; used in lubricants and adhesives and coatings and synthetic rubber and electrical insulation [syn: silicone polymer]"
Silicone is different from Silicon and Silica, though it contains a relatively high proportion of silicon. Silicon, which is found in rocks and sand, is the second most common element in the crust of our earth. It is not found in its elemental form, but occurs mainly as oxides and silicates. Silica is a three dimensional network of silicon dioxide, most commonly encountered as sand. Silica exists in crystalline and amorphous forms, is chemically resistant at ordinary temperatures, and can undergo a variety of transformations at high temperatures (greater than 500ºC, 950ºF) and pressures.
The basic difference between silicone polymers and "organic" polymers is in the molecular make-up. Silicone or Dimethyl Polysiloxane, is made up of silicone/oxygen linkages, the same found in high temperature materials such as quartz, glass, and sand. Natural rubber, or organic polymers, are made up of carbon/carbon linkages.
Through altering the chemical make-up of the silicones by adding phenyls, vinyls, and fluorines, significant variations in physical properties can be achieved. But these alterations are often responsible for creating toxicity.
Basically, we haven't a clue what is in our particular tyres and jonny is right about the potential dangers.
Thanks for that Tropi. I`m not trying to be alarmist guys, I hope it`s not dodgy. It`s just that I`ve been around this stuff and I know from experience that there are those that cut corners. To cut costs it is possible asFfergy mentioned , to use fillers/additives. Some are safe but most when eroded are not. Light weight filler does not break down in the human body for example and can cause you a real problem. Even the talcum powder used to fill out resin and rubber is not good and sometimes is used to line a mould.
The dust given off is a real problem and as Fergy outlined, a 100% pure silicone rubber will just degrade safely with wear. Anything that gives off dust is suspect as is the price. As an indicator a pea sized portion of high grade silicon , which is what I use, costs around 50 pence. So a set of tyres should come in at what price? You do the maths but be careful guys!
Finding the compound of Ortmann tyres is one of lifes holy grails.
What I will say is that (health and safety aside) they are incredible on Carrera, wood and Scaley Sport but not worth the money spent on Ninco and Scaley Classic.
I DO know their silicone content is very low but do not know more than that. I have a complete list of Ortmann tyres made and will do an article on that very wsoon, now that I can relax a little at Swiss Race Bahn (more soon on the opening weekend) BUT . I have a few long overdue commitments to people to do first (post wise)
QUOTE If you had asked this last week I would have said yes now I would say no because if a new racer turned up with a box stock car then he would be at an immediate disadvantage
Interesting quote Grah1.
In the recent Audi Challenge at Wrexham, there was a distinct advantage to the cars being driven on Ortmann tyres, which is great if you were aware of the fact that:
a - Ortmann tyres were classed as rubber tyres and therefore legal within the rules of the competition.
b - Any other combination of tyres used would be rendered virtually useless because of the residue left on the track by the Ortmann tyres.
c - able to obtain a supply.
I know of one team who turned up at Wrexham with no knowledge of these tyres.
I think in the interest of the competition alot of thought should be given to the legality of these tyres.
Come on Inte, as a regular 'user' what are your thoughts about Ortmann - a balanced opinion would be good to help decide.
I understand that Ortmanns are made from a racing rubber compound called 'Speedy Weasel', though quite what goes into the compound I don't know. They certainly do not behave like a silicone tyre - they will stretch and will not split, for instance. I disagree with Swiss' regarding their performance on Scaley Classic, I have to say. On my home track (about 50') I get a 3/10 second improvement on lap times on mag cars, seemingly regardless of what original tyres were fitted, and it's more than that with non-mag cars. There's more info at www.rsslotracing.com, who bring them into the U.K..
In Europe 3 types of tyres are most commonly used, Hard rubber, Silicon or Polyutherane and Sponge.
Sponge Offers the biggest grip, but only on "permanent" tracks. Doesn't matter if its routed or plastic, as long as its dust free and has a thin layer of rubber deposit. Scaleauto, Sigma and GP Speedtyres al make suitable sponge tyres for 21 rims. Sponge comes in hard and soft compounds indicated as Shore. The lower the softer, picking the right compound is sometimes a true Black Magic.
Silicon or Polyutherane
In Europe also know as Ortman/Wiesel tyres. Both Messrs Ortman and Wiesel have their own "secret" recepy form which they pour their "rubber" into the tyres mold. The good thing about these tyres is that they offer instant grip on any clean surface, and will continue to do so even after the car has been "shelfed" for months. Downside is that becuase they are quite hard, they have to be "trued" perfectly round. Which can be difficult if you dont have a tyre truer.
believe it or not, but the hard rubber tyres that are supplied with most model kits can be used, and if treated with a bit of oil or petrol will provide reasonably good grip. Not something to try at the local club track, but for home use it will do and hey...they were in the kit anyway. Best rubber is found on Tamiya an Hasegawa kits. Even if you dont use the rears, the fronts can always be used. A good trick is to coat the fronts with some Cyanoacrilite glue and polish them with 1200 wet sandpaper. This will decrease the roll resistance of the car.
hmmm...the thing I've found with Ortmanns is that they are so easy to true it's..er..untrue. Fine grade sandpaper will true them literally in seconds. One great thing about them is that they retain the same characteristics throughout a race. When 250GTO and I used them in the Wrexham 4 hour last year, driving one hour stints, the car felt the same at the end of the hour to how it was at the beginning.
hi guy,s Michael makes the tyres i suply for my kits, i have asked him what they are made from, he tells me they are resin based.they true very quickly with fine wet and dry, there is an advantage on sports track , but on sandtex or poly surfaces there are better ttyres to be had. hope this helps macp
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