Why aren't tires in model kits made of rubber?

[Greg Myers]

After receiving a great set of tires from Alan Raab of MA'S Resin made of rubber, I was wondering about this. Back in the day, Revell had several kits with rubber tires as well as the early Monogram kits.

[Harry P.]

Just a guess here... but cost?

[Greg Myers]

Ah yes, Dry-rot I forgot. So it's damned if you do and if you don't. Although the old Monogram Rubber tires hold up.I just got some from Alan Raab of MA'S Resin and they look like they will hold up as well. Seem to be of the same material as the Monogram tires.

Edited November 2, 2010 by Greg Myers

[Greg Myers]

Just a guess here... but cost?

I suppose there are probably many other things too.

[Harry P.]

There is flexible rubber-like resin out there. Great stuff for casting tires.

I just bought a pair of aftermarket tires for a Pocher kit made of soft black resin. Looks and feels like rubber.

[Jon Cole]

What tire melt?

Model & photos courtesy Karl Sheffer

[Greg Cullinan]

I like whatever Modelhaus uses,it is delicious.

[Harry P.]

I like whatever Modelhaus uses,it is delicious.

What flavor is it?

[Greg Cullinan]

Why black licorice of course.

What flavor is it?

[Art Anderson]

As others have alluded, there just isn't a pat, easy answer. Early on, when soft tires were included in a model car kit, they were rubber--most generally neoprene (the same stuff used for rubber fuel lines), but even that has a limited life. Strombecker, before they introduced slot racing sets, produced a line of 1/24 scale model car kits which were motorized, steerable front ends, and used neoprene rubber tires. Monogram's earliest model car kits having "soft" tires also used neoprene rubber tires, which for them came from a source outside the company--a toy mfr who had the equipment and the knowledge to work with neoprene, and were already producing prodigious quantities of rubber tires and components for the toy industry.

PVC (Polyvinyl Chloride) has been around for more than a century, and in the 1930's, chemists learned how to formulate the stuff so it had flexibility, softess. However, that came at a price, as the early, soft flexible PVC had some "plasticizers" which when placed in contact with hard plastics such as "Tenite" (DuPont's acetate plastic) and the subsequent styrene and polystyrene plastics with which we model car builders are acquainted, those plasticizers attacked the hard plastics, softening their surfaces (tire burns) and would even attack most enamels and lacquers--especially decal sheets, which are produced with lacquers. Early AMT promotional models used a very hard PVC compound for their tires, and never experienced any problems, but with the beginnings of plastic model kits of cars, they went to the softer, plasticized PVC, and there the problems cropped up; and Revell kits had that very problem, in spades as well.

By the late 60's however, it became possible to produce soft PVC tires which didn't leach out those plasticizers, at least not enough so as to just simply melt down a styrene wheel overnight before your very eyes, and with the fairly brief "PVC Monomer Gas" scare of aabout 1975-77, the problem became less and less an issue for manufacturers and hobbyists alike.

But why not Neoprene? Neoprene has to be vulcanized, just as with natural latex, but it's still problematical as to how long those tires will last once on the model--Neoprene, like most other moldable rubber compounds, oxidizes readily in the open air--exposure to light, natural sunlight or artificial accelerates the problem, Add to this unsatisfactory characteristic the simple matter of cost: Molding and vulcanizing neoprene takes a lot more time per cycle of the molding machine that the production cycle of an injection molder shooting PVC into steel dies. Of course, the Japanese kits are produced with far less concern about their ultimate pricepoint unlike us in the US (or countries where model kits are made for the US Market), but domestic/offshored model kits are much more cost-sensitive than those made in Japan for their domestic market.

Oh well, I've gone on a bit long here.

Art

[kitbash1]

WOW After seeing the pictures of the melted tires on that funnycar model, I went and checked some of my older Tamiya and Protar F1 kits for dryrot. Kit tires that have sat around in their boxes for 10 to 20 years or longer, showed no signs of this problem. I think that the way I store my kits may help. I keep my kits in my basement hobby room and only a few kits are still shrink wraped. The room is not damp or too hot or cold. The temp. in the basement is around 70 to 72 degrees year round. But I did notice that one of my old MPC McLaren Mk8D kits tires were starting to show some sort of weirdness.

[LDO]

For the life of me, I'll never get why modelers insist on having tires that are soft and molded in black. Model cars don't have metal engine blocks. They don't have any parts made of carbon fiber. Model Corvettes don't have fiberglass bodies. Seats aren't covered in leather/suede/vinyl.

Years ago, a Kiwi friend sent me several sets of 1/8 scale wide whites copied in resin. I took them to a model car club meeting and no one wanted them...at no charge...because they were in white resin.

[Railfreak78]

For the life of me, I'll never get why modelers insist on having tires that are soft and molded in black. Model cars don't have metal engine blocks. They don't have any parts made of carbon fiber. Model Corvettes don't have fiberglass bodies. Seats aren't covered in leather/suede/vinyl.

Years ago, a Kiwi friend sent me several sets of 1/8 scale wide whites copied in resin. I took them to a model car club meeting and no one wanted them...at no charge...because they were in white resin.

I have a really nice set of white resin tires that was mixed in an old kit I bought and They look really great. I'd certainly take more if I had the chance. Whats a little more painting?

[Jordan White]

LDO: probably because rubber tires are hard to replicate without actually using rubber IMO. Usually the engine is painted, so you wouldn't know if it's metal. Carbon fiber can be done with decals. Corvette bodies are painted, and seats can be painted to look like leather or can be covered.

Plus with rubber tires, you can easily make them squat, bend, and ripple like real tires.

Edited November 3, 2010 by Jordan White

[Greg Myers]

"Oh well, I've gone on a bit long here. ART"

Yes you have,but you most certainly have answered all the questions anyone could have ask on the subject. Thank you very much.

[Greg Myers]

For the life of me, I'll never get why modelers insist on having tires that are soft and molded in black. Model cars don't have metal engine blocks. They don't have any parts made of carbon fiber. Model Corvettes don't have fiberglass bodies. Seats aren't covered in leather/suede/vinyl.

Years ago, a Kiwi friend sent me several sets of 1/8 scale wide whites copied in resin. I took them to a model car club meeting and no one wanted them...at no charge...because they were in white resin.

So I think you are saying we shouldn't strive for realism? I wonder what Gerald Wingrove was thinking about when he built the lovely Bentley above, replicating 1:1 materials throughout his build?

[2002p51]

For the life of me, I'll never get why modelers insist on having tires that are soft and molded in black.

I'm with you.

I wish all model cars "tires" were made of the same plastic as the rest of the kit. It's much easier to make them look real with various paints.

I do like resin tires, like those from Modelhause and others. But rubber or the usual vinyl, hate 'em!

[Jordan White]

I wish all model cars "tires" were made of the same plastic as the rest of the kit. It's much easier to make them look real with various paints.

Easier to make them look real than real rubber?

Edited November 3, 2010 by Jordan White

[Jordan White]

Alright, I get it now!

Course I'll still stick with my rubber tires thank you very much!

Oh, I thought of something else, rubber tires are much better if you want to mount a narrower tire on a wider "wheel" or a narrower wheel on a wider tire, such as on off-road vehicles! Ha!

[Brutalform]

Alan's tires are the best I've used so far. I bought a few, and just love em! Found some nice wrinkle walls on the Slixx decal website. I figured I give them a try too, since they also have "deep" rear steel rims for sale too.

[62rebel]

don't forget the late seventies two-piece hard plastic tires; AMT had SEVERAL different designs for their various kits and while i hated them with a passion THEN, i think they're more durable and less likely to melt plastic than the pvc tires...

the trick to getting them to look right was sanding down the mating edges and rubbing them down to reduce the shine.

[Modelmartin]

An added disadvantage for "rubber-like" tires is that you get just so many stock sizes to fit everything. There are way more tire sizes used everyday in 1/1 cars than there have ever been in 1/25-24 scale. That does not even cover older, obsolete sizes used in older cars.

With plastic and resin you can produce whatever CORRECT or DESIRED size is needed cheaply and quickly.

You "rubber" tire guys need to move on!!!

[LDO]

So I think you are saying we shouldn't strive for realism? I wonder what Gerald Wingrove was thinking about when he built the lovely Bentley above, replicating 1:1 materials throughout his build?

I didn't say we shouldn't strive for realism. In fact, I believe I said we should...but with paint, instead of molding tires in rubber.

I wonder why we can't buy a 1/15 scale Duesenberg with a body of hammered brass & copper, an engine of machined metal, and an interior of leather and wood...at Wal-Mart for 18 bucks?

[Chuck Most]

I wonder why we can't buy a 1/15 scale Duesenberg with a body of hammered brass & copper, an engine of machined metal, and an interior of leather and wood...at Wal-Mart for 18 bucks?

Because Wal-Mart no longer carries model kits! (Rimshot...)

[Greg Myers]

Because Wal-Mart no longer carries model kits! (Rimshot...)

Were you there too? Back in the mid seventy's I bought several Pocher kits there for $20 each.:lol: