I have the 1/35 scale Italeri M-923 A1 Big Foot kit & was planning to do the build & I've been browsing through the reviews & all that stuff regarding this particular kit. Based on the reviews, the tires that comes with the kit doesn't look realistic so I got a AM set from Hobby Fan. Now my question is, is there a particular direction that the tread of these tires have to be in when installed or is it like in any direction?

-notice the front tires on this box art.

-the left two rear tires on these one.

The tires are unidirectional. They can be put on in either direction, doesn't matter. That is why the look differnt on the box art and the HEMMET in your second pic.

This is not quite true. By design these tires are directional and should in theory be all installed in the same direction. When you look at the front of the vehicle, pattern should be like that:


At least this is how Michelin wanted it to work, when they designed XL tire tread. In practice however it only makes logistics more difficult as tires have to be put differently on different wheels of the truck. Please note that the same rim is used on front and rear wheels, but what is outer rim side on front wheel becomes inner side on rear wheel. This means that to achieve correct pattern, as Michelin designed it, tire on the front wheel would have to be put on rim differently from rear wheels. And of course tires on both vehicle sides also would have to be in different directions. This of course also means that spare wheel tire direction is correct only for some wheel positions...

Below horizontal blocks represent "front / outer" side of the rim, which becomes back / inner side on rear wheels.


US Marines trucks usually have tires on them according to this "proper" scheme. But US Army found that Michelin XL tires work just as well when used "the wrong way" and to simplify logistics their trucks (at least M939 series ones) usually have tires this way:


Note that all tires are put on rims in the same direction - you can swap any two wheels and the pattern will still be as on the picture. Of course spare wheel would also be assembled this way. This is what you see on the box art of Italeri kit. In reality it sometimes happens that tires are quite randomly put on wheels, but what I shown above is most common.

Pawel

The one way you can tell for sure is looking at the real tire, even a lot of tire men don't even know that it is there, but on the sidewall of the tire is an arrow, and it is a tiny arrow, so that is why so many miss it. Most of the time it is all by itself, or it could be hidden by the brand name

When there is a tiny arrow on the sidewall, that means it is directional, some companies do put on a little bigger arrows then others, and some you really haft to search for, but I have seen companies put them on back-wards for years without much effect, cause they never knew that the arrow was there.

Now the arrow is supposed to be in the direction of the rotation of the tire, to make it last longer. If you ever get by one, look real close at the side walls, and if you see a little tiny arrow, that is what it is for.

Another-thing tire mounters usually don't know is, on tires like Bridgestone, when they are brand new, they have a little colored dot, on the sidewall, that isn't there for art work, that is supposed to be lined up with the valve stem, on the rim, with factory balance. You still might haft to balance it after-wards, but not as much, I have had some that never even needed balancing when done right.

The thing of it is, when these tire companies come out with these new ways to help you, and you got an old tire man that is set in his ways, and he don't think he needs to do it, so you end up with tires put on back wards, or wrong.

Thanks for the info guys.

I think you read too much into the reason why the tires are facing different ways. It is not to simplify logistics, it just does not matter what direction the mechanics mount the tire on the wheel. Not to say they are being negligent, but that it really doesn't matter which direction the tire is facing. When you mount the spare to replace a flat, there is a 50-50 chance that it is facing the "wrong" way when you put the tire on. Then when the mechanics put a new tire on the wheel that is about to become the spare, does it really matter which direction the tread pattern is facing? The next time you use that spare, it will have another 50-50 chance of being the "wrong" way once again.

So in the end, there is no right or wrong direction to mount the tire treads.

Rob,

There must be some good reason why on 90% of my photos of Army M939s with Michelin XL tires, they are mounted the way I shown above. Not randomly, but exactly that way. Sometimes I believe in coincidences, but this is hardly one

Even M923A2 and M931A2 on photos in your motorpool gallery have tires mounted strictly according to the "plan" I scetched above :-)

Pawel

Most likely because they came from the factory that way. We don't rotate tires as a general rule. Also, unless a vehicle is in the field or on the road, when a flat is discovered, it is replaced or repaired on the spot. When the tire is removed to be replaced on the spot, the mechanics will replace the tire in the same direction the flat tire was facing.

But of course I really don't know what I'm talking about. It's not like I was a battalion maintenance officer for an armor battalion that had several dozen HEMTT, 5 ton, 2½ ton trucks or command a maintenance school that trains over 400 soldiers a year on maintenance of vehicles like the HEMTT, 5 ton, 2½ ton trucks and FMTVs. Oh wait, I do.

Indeed this may be the case. I assumed that it was Army idea, because as I wrote earlier almost all Marines trucks on my photos have tires monted all facing the same direction in relation to the truck. This is the way XL tires are mounted on lots of other military vehicles used all over the world (e.g. French VAB, German Fuchs and Luchs, even British Land Rovers). At the same time almost all Army 5-ton trucks on my pictures have tires facing the same direction in relation to the wheel rims, what means that they are not the same direction in relation to the truck. And I'm talking about several hundred photographs here...

I do not try to insinuate that you don't know what you talk about! I apologize if you think I did. You sure know lot more about it than I ever will. But what you wrote only means that I was most likely wrong about the cause why tires are mounted this way on Army trucks, but not about the very fact that they ARE indeed usually mounted this way.

If 5-ton trucks were arriving from the factory with tires mounted this way - what would be indeed easy to explain, as mounting all tires on rims in the same direction makes installation of large numbers of them on a production line easier - then interesting question is why Marines trucks usually have tires mounted differently?... Maybe reason as simple as different production runs at the factory?
"Usually" is a key word here - I have photos of Marine trucks with tires mounted in "Army" way, and photos of Army trucks with tires mounted in regular "Michelin standard" way. I also have photos of trucks with completely random tire directions.

Here is a small photo collage of 5-ton trucks:
US Army:


US Marines:


By the way - I of course know that this whole discussion has very marginal importance to majority of modelers, but I find this little mistery interesting...

EDIT: I just noticed that on my photos above all Army trucks are A2 models, while Marines trucks are A1 models - maybe this is the answer?!

Pawel

Cardinal : Alex

I hope this thread has removed any doubt... on what direction the tire treads are positioned.

Some times I have to just sit back ... and have a good chuckle.

Jim

:-) :-) :-) :-) Well, when in the service, I was taught there was the right way, wrong way, and the Navy way...... and we did things the Navy way...... like it or not...... :-) :-) :-) :-)
I now work for the State of New Jersey..... and there is the right way, wrong way, and the Joisey way........
:-) :-) :-) :-) :-) :-)
I actually believe that if I was the poor sod who had to hump a 2 or 3 hundred pound tire and replace it, I wouldn't give two hoots not to mention two cr*ps which way the tires were facing..... round and inflated would be all that was required........ :-) :-) :-) :-)

Amen to that!

I hear you, I doubt any guy who has to change those tires in the field is thumbing through the manual going ... "Now which way do they face ... hmmm?"

My guess would be they are thinking ... does it have air? is it round? can it be made to fit?

But hey .. I travelled on LPC's and they do have a certian why of being put on.

there is enough information on this topic now



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