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Regarding the topic of tires


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#1 raildogg

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Posted 24 November 2012 - 08:29 AM

First, I must admit this topic is, a thorn in my side. I have strong opinions and feelings about it, that, may be considered "out there". I want the model manufacturers to make them fit, which despite modern mold making technologies, seems impossible for them. I have fostered ideas to anyone who would listen, and still results are not forthcoming. Recently while looking for something unrelated I happen upon an image that gave me another idea, I'm full of'em, ideas I mean. LOL. What if the tire was made so that the inner diameter was adjustable by the modeller himself !! So is that so difficult. Or since the majority are some kind of flexible material, deliberately make them smaller. I should think that, changing the molds where the tire impression are made can't be that expensive. C'mon they make changes all the time. See, I can get crazy sometimes. And making my own tires is not cost efficient. Instead of another '32 Ford or Model T let's have tires that fit.

#2 Draggon

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Posted 24 November 2012 - 02:51 PM

Funny how the Japanese can make awesome tires and wheels, but we in he states get, best to say, freakin' garbage.Witness the Oaki/Arii slots.

#3 Chief Joseph

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Posted 24 November 2012 - 04:24 PM

If the manufacturers would just take a cue from the real world, where a 15" tire will fit on any 15" wheel of the appropriate width, we wouldn't have so many problems. But the manufacturers have their own ways of doing things, and it's really not their job to make sure the tires they put into kits can be used with some other manufacturer's wheels. My biggest beef is with how they re-use the same old tires across several kits, whether those tires are appropriate for the subjects or not. I'd rather see accurate styrene tires in two halves instead of inaccurate vinyl tires. I took matters into my own hands for my models, but I know not everyone can do that.

#4 Jordan White

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Posted 24 November 2012 - 04:55 PM

Better yet, make the wheels so they are one piece wheels, like the Japanese do. Two piece wheels are pretty ridiculous, since they both look unrealistic and they mean that you won't have wheel backs to use for any extra wheels that may come in the kit. If they had one piece wheels, then they could more easily standardize tire sizes.

#5 Art Anderson

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Posted 26 November 2012 - 10:47 AM

First of all, virtually every model company from the US used (and AMT, Revell Monogram, and Moebius certainly still do) use a standard tire, or series of tires in their model car kits. That is something which goes all the way back to 1958 and the first AMT 3in1 Customizing kits, carried forward into their Trophy Series kits as well.

With the rise of the Japanese model kit industry in the 1970's, once they began doing, seriously. model car kits, companies such as Tamiya, Hasegawa, Aoshima and most all the others, went to outside suppliers for their tires--my understanding is that Shuzoka City, Japan was at one time, heavily dotted with small, almost mom-and-pop operations with perhaps a couple of small molding machines, producing both wheels and tires.

Now, enter a bit of tradition here, if I may: With any mass-produced model car kit, tooling for the tires is expensive, often second only to the multiple slide tooling used to create the one-piece body shells we all have preferred since AMT started making model car kits seriously back in 1958. In addition, model car kit tires in just about every brand of kit today, with the exception of those which come from Italeri tooling, are soft material, not hard styrene, in order to give us tires that have at least some semblance of tread detail. In serious mass production, in-house (which is how AMT/Round2, Revell, and Moebius kits in the US, and I suspect Revell of Germany in Europe) tires tend to be made in molds (dies if you will) which produce upwards of 48 tires at a single cycle of the mold machine, and using PVC (Vinyl) which is a completely different plastic material than the kit itself is molded in. This means a dedicated molding machine (or machines) which do nothing but mold tires. Now, with a tire mold that can cost 10's of thousands of dollars to cut, and a very large injection molding machine that likely can cost upwards of a million dollars new, that's a very serious investment, is it not? To this, add in that PVC once cooled enough to be demolded (PVC, just like styrene, is heated until molten to about the consistency of pancake syrup for injecting, is actually quite abrasive when it must slide sideways against even hardened steel, which is what happens when the tire tread area is pulled or pushed out of those mold cavitites. In the roughly three years that I was involved in product development for Johnny Lightning diecast models at Playing Mantis, we faced having to replace several tire tools which made the soft PVC "scale appearing" tires we used in many programs--even those tiny tire molds were expensive, generally about twice the cost of the entire diecast and plastic tools used to make any one single JL car--generally after about 1 million cycles or so. The same was, and likely still is, true of larger 1/25 scale PVC tires.

Now, I know that the Japanese companies make some superlative tires for their kits--but with them, generally speaking, cost has been no object (for decades, US companies had to live with very rigid price points for a model car or truck kit, just now beginning to go away with the elimination of mass merchants from the equation) given that traditionally, Japanese manufacturers could price any new kit based largely on its development cost, rather than being constrained by some artificial price structure dictated by a big-box retailer. Hence, they have been able to use some synthetic rubber or another, which makes for a really gorgeous tire, but at both a higher cost for the tooling, as well as a slower production rate in all likelihood. In addition, neoprene rubber (which I suspect is what Japanese kit makers have used all along) doesn't have nearly the life of PVC--I, along with others, have witnessed those beautiful rubber tires drying out, splitting and cracking over the years--something that seldom has been an issue with PVC tires.

Some have said, in this thread even, "Why not highly detailed hard styrene tires?" Well, for starters, styrene plastic cannot be pulled out of a mold having engraving making recessed, even raised details, as styrene plastic, once cooled to demolding, will not flex out of the way of any engraving, if pulled at all sideways against that engraving. To come up with anything like accurate tread detail in a hard styrene tire, even were it made in two pieces to be glued together, would require a mold made of multiple segments around the tread. That, if done to any acceptable standard of mold alignment to minimize or eliminate mold parting lines around that tread would be frightfully expensive--so how many more $$ is anyone of us willing to pay for a car kit having such tires? My suggestion would be that the marketplace (you, me and the other guys too) would scream like so many stuck pigs, and likely vote with our feet, and our dollars elsewhere.

So, I see it as a tough compromise, but a compromise none the less.

Art

#6 johnbuzzed

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Posted 26 November 2012 - 10:58 AM

Art, how do some manufacturers provide modelers with well-engraved, curved parts for aircraft, such as fuselages and engine cowlings?

#7 dmk

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Posted 26 November 2012 - 11:45 AM

I'd rather see accurate styrene tires in two halves instead of inaccurate vinyl tires.

I think this would solve a lot of problems with tires. Aircraft and scale military vehicle models (wheeled armor and trucks) have two piece styrene tires and wheels almost exclusively. They can make them accurately and relatively cheaply.

The fact that the manufacturers have chosen to standardize on vinyl tires has both increased their expense and reduced the fidelity.

Edited by dmk, 26 November 2012 - 11:47 AM.


#8 Art Anderson

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Posted 26 November 2012 - 02:23 PM

I think this would solve a lot of problems with tires. Aircraft and scale military vehicle models (wheeled armor and trucks) have two piece styrene tires and wheels almost exclusively. They can make them accurately and relatively cheaply.

The fact that the manufacturers have chosen to standardize on vinyl tires has both increased their expense and reduced the fidelity.


How much are you willing to pay for accurately done street tires made in styrene! That tooling alone, to create anything like an accurate tread pattern would most likely involve a very complex mold, with at least 8 moving sections--now reproduce that tool into a multiple mold base large enough to mold more than one set of tires at a time. And, I dare not mention, do I, the problems of mold alignments and parting lines? Don't confuse this with making hard styrene military combat tires--they don't have anything like the intricate tread pattern of any street tires.

Art

#9 Art Anderson

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Posted 26 November 2012 - 02:27 PM

Art, how do some manufacturers provide modelers with well-engraved, curved parts for aircraft, such as fuselages and engine cowlings?


John,

There is a vast difference between molding an aircraft fuselage in two halves, with relatively faint engravings, and a tire having the intricate, and fairly deep grooved tread patterns in hard styrene. I'm not saying it could not be done, but I have pointed out that such a tire mold for making styrene street automobile or truck tires would have to have many more segments than any aircraft fuselage, in order to just get the tire out of the molds once cooled and hardened. Styrene is not at all flexible, and it won't move sideways out of the way of engraved tooling as will either a soft PVC or neoprene rubber. Just take a good look at the tires in any Italeri car kit having styrene tires, you will see what I mean. And in addition, the tooling, and possibly the production costs as well, could very well be more than for any one-piece body shell--and that mold is the most expensive tooling in just about any model car kit.

Art

Edited by Art Anderson, 26 November 2012 - 02:29 PM.


#10 Chief Joseph

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Posted 26 November 2012 - 03:23 PM

Instead of relying on a complicated multi-part tool like those used to make body shells, how about this: mold the two sidewalls as halves and the treads as six to eight individual sections that are placed around the tire casing. This approach uses a little more plastic and would take up another sprue, but it allows great sidewall detail and accurately-engraved tread without having to worry too much about the draft angles on the mold. I think with modern methods and tooling we could get very tight-fitting parts that would not require a lot of extra work to look good. Car models are certainly not the only segment of the hobby that suffers from tire woes... look at how many aftermarket resin tires are available for all kinds of airplane models. I remember when resin parts were first starting to come onto the airplane scene and replacement tires were among the very first parts introduced.

#11 Jordan White

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Posted 26 November 2012 - 03:53 PM

Art, are the reasons you outlayed above also the same reasons that NOBODY, gives us a correct looking radial tire with the proper bulge at the contact patch?


I'm thinking it's more due to the fact that the kit manufacturers think that people want rolling tires on their plastic models.

#12 Art Anderson

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Posted 27 November 2012 - 04:06 AM

Instead of relying on a complicated multi-part tool like those used to make body shells, how about this: mold the two sidewalls as halves and the treads as six to eight individual sections that are placed around the tire casing. This approach uses a little more plastic and would take up another sprue, but it allows great sidewall detail and accurately-engraved tread without having to worry too much about the draft angles on the mold. I think with modern methods and tooling we could get very tight-fitting parts that would not require a lot of extra work to look good. Car models are certainly not the only segment of the hobby that suffers from tire woes... look at how many aftermarket resin tires are available for all kinds of airplane models. I remember when resin parts were first starting to come onto the airplane scene and replacement tires were among the very first parts introduced.


Ahhh, but to play the "Devil's Advocate", I can well imagine that any product or brand manager would look at that and wonder why--considering how loathing model car builders are of multipiece body shells. And, I can't visualize many model builders being enamored with the idea of having to clean up all those joints after assembling all those parts.

Art

#13 Art Anderson

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Posted 27 November 2012 - 04:11 AM

Joseph I don't think it would require that many parts. There's no reason with that design the tread needs to be more than two halves. One split at the contact patch and the other at the top. One outer sidewall, one inner. Four pieces total per tire.


Except, that the more oblique the angle of a surface is to the raised detail on a mold one of two things: Either that detailing gets badly munged in order to be able to pull a half circle part out of a half-circle mold, or the steel tooling will merely shred the hard styrene unacceptably. Indidently, this is the exact same reason that model car body tooling has to be itself, multi-piece--as if it weren't, the step of pulling that styrene body out of a one-piece cavity would simply tear off the likes of door handles, side trim, even gently engraved badges and scripts. Please keep in mind, with styrene injection molded kits, we are NOT talking about flexible rubber molds here.

Art

#14 Art Anderson

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Posted 27 November 2012 - 04:14 AM

Art, are the reasons you outlayed above also the same reasons that NOBODY, gives us a correct looking radial tire with the proper bulge at the contact patch?


Jacen, the tire bulge at the contact point would be very possible, I'm quite sure. However, I wonder how that would play out in actual practice (it has been done, in the past, with 1/48 scale model aircraft tires, and apparently didn't cause enough stir for more than just a very few kits made with tires done that way.

Art

#15 Harry P.

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Posted 27 November 2012 - 04:37 AM

Here's an idea.

Mold the two halves of the tire in styrene, like the rest of the parts, with a shallow "trough" around the perimeter where the tread will go.

Mold the tread itself as a flat strip of flexible PVC.

Glue the styrene halves together and paint them. Then take the tread strips, sand the surfaces down to get that scuffed look, and wrap the tread strips around the tires. If engineered correctly it will be a friction fit in the styrene tire. Or a dot of CA will hold it in place.

That way you get both crisp sidewall detail and crisp tread detail, and no need for fancy multi-part molds.

#16 Chief Joseph

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Posted 27 November 2012 - 05:26 AM

Ahhh, but to play the "Devil's Advocate", I can well imagine that any product or brand manager would look at that and wonder why--considering how loathing model car builders are of multipiece body shells. And, I can't visualize many model builders being enamored with the idea of having to clean up all those joints after assembling all those parts.

Art


So you don't think many car modelers would want to tackle the Individual track-links found in so many tank kits? :D
I suppose for now we just have to either accept the tires that manufacturers put in the kits, or opt for aftermarket tires made with other mold technology. When personal 3D printers are cheap and good enough, we'll just print tires in one seamless piece!

#17 Gluhead

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Posted 27 November 2012 - 06:23 AM

Here's an idea.

After making a couple of my own tires out of parts of other tires for a particular project, I've often thought this would be a good way to go...at least for some tires. For some tires, the shape of the shoulder and detail that rides over from one plane to the other would make for too conspicuous of a seam, no matter how well it fit. But for the former, I'd love to see this.

Thanks, Art, for the insight on the manufacturing conundrums faced here. With how much we're able to accomplish on a small scale with resin, I think we sometimes lose sight of what it takes to produce some of this stuff on a mass production level.

It does make one wonder, though. You mentioned tooling which produced 48 tires per pull, as well as a die needing replacement after a million or so cycles. I'm likely mixing bags of potentially mis-matched information here, but it begs the question; Are kit manufacturers really producing nearly 50 million of a given tire?

Either way, we really don't have it all so bad, as it is. We could be having to whittle them out ourselves, after all. :P

#18 raildogg

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Posted 27 November 2012 - 06:37 AM

Wow!, what a firestorm!. If they made tires like Tamiya does we'd all be satisfied. I think they have the best tires in both accuracy and fit. I also like the idea of wrapping the tread detail around a styrene carcass. It would lend itself to some fine script engraving on sidewalls. If done correctly they could be made of styrene also, made thin so they would flex too.The tread pattern strips could then be varied as to type make and size. Laid out flat all kind of details are possible, even the flat side bulge to show a weighted stance.. And I've never met a modeler who wanted to roll his models about, at least in my travels. What with the prices climbing you'd think they would be willing to keep we buyers very happy, yes?.

#19 Chief Joseph

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Posted 27 November 2012 - 06:57 AM

If they made tires like Tamiya does we'd all be satisfied.


+1 to that, sir. So the question remains, "why don't they?" "It costs too much" is no longer a good excuse since the big chain discount stores rarely sell models now.


Actually, I'll retract that question. Old kits will not be retooled to fix their tires and wheels-- it just isn't going to happen. Some of the brand-new kits we are getting have decent tires in them, with some reservations. It will always be the model builder's option to scratchbuild or buy something better than what the kit provides.

Edited by Chief Joseph, 27 November 2012 - 07:33 AM.


#20 Casey

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Posted 27 November 2012 - 07:56 AM

I suppose for now we just have to either accept the tires that manufacturers put in the kits, or opt for aftermarket tires made with other mold technology.


I think that's the best solution for now. Eventually, more options will be available (no pressure, Joseph! :lol:), and I think more builders will see the advantages and embrace "hard" plastic or resin tires, and welcome finishing them just like any other styrene kit part, instead of settling for what's included in the kit. ^_^