Airless tyres

[red750]

Michelin in the US have developed airless tyres, first for the military, but will be releasing them for road cars later this year. No more punctures.

 

[onetrack]

They're called Tweels (combining the words Tire and Wheel) and they've been available since 2012. Scroll down the page below to the FAQ's. Michelin actually invented them in 1990, but it took a lot of work to perfect them.

 

https://business.michelinman.com/by-technology/michelin-airless-tires#:~:text=The term “TWEEL” is the,center in Greenville%2C South Carolina.

 

Edited February 27 by onetrack

[old man emu]

The first thing that I thought of, after recently having to remove and replace a tyre/wheel assembly, was that these tyres would be much lighter than what they replace. Since weight is the enemy of fuel consumption, these tyres might provide a smidgen of lowering of fuel usage for a vehicle. It might not have much financial benefit for the individual, but over the whole national fleed it could be significant.

 

Also, it seems that the structural polyurethane making up the spokes and hub can be recycled. Those spokes reduce the amount of difficult to recycle rubber used in a tyre.

[nomadpete]

Curiously, Michelin do not mention the weight, compared with conventional hollow tyres.

 

If they are lighter, they reduce the unsprung weight, which in turn improves the comfort of the ride.

 

Nor does it compare the deflection resistance.

 

But it does imply that although they have double the mileage, they are more expensive. Cost per mile up or down?

Edited February 27 by nomadpete

[spenaroo]

they have been running mousse tubes in off-road bikes for years.

problem is there is no adjustment in tire pressure available.

so cant let them down when in sand, or pump them up for highways.

 

they aren't really used except by the hardcore enduro guys.

Ive never used them, but been told it feels like riding on a flat

 

also an absolute PITA to fit

Edited February 27 by spenaroo

[Mr.Vegemite]

I was about to mention the same thing. 4WD tyre pressures. 

[nomadpete]

4WD - imagine the balance issue when the tyre is clogged with mud!

[old man emu]

2 hours ago, nomadpete said:

Curiously, Michelin do not mention the weight, compared with conventional hollow tyres.

I wouldn't worry about that not being in the information on the webpage. You have to remember that the webpage is in the realm of advertising - just getting people interested. If I was really into the specifications and performance information, I'd look elsewhere in Michelin's publications.

 

Like a lot of automotive developments, these tyres seem to be aimed at a niche market - low speed, off-road use. It would be another line of development to get them suitable for light passenger vehicle use. 

 

I wonder how much noise would be generated as that open honeycomb shape moved through the air. Worse than a Landcruiser with mud tyres whizzing down the highway. 

[spacesailor]

When you ' weigh ' a car , you weigh what it " sits " on .

So that , wheel weight , should be deducted from the vehicle total weight .

There is no wheel weight pressing down on the axles. 

But the opposite .

The axles are pressing down on the wheels .

Just like my exam question " what causes icing " .

spacesailor

[willedoo]

8 hours ago, nomadpete said:

4WD - imagine the balance issue when the tyre is clogged with mud!

Another issue would be if you drove off road and got decent sized stones jammed in the honeycomb. If you didn't check the tyres every time before driving back out on the bitumen, you would risk hurling largish stones at speed.

[old man emu]

1 hour ago, spacesailor said:

There is no wheel weight pressing down on the axles. 

Spacey, I thought you were British. A statement like that makes you sound like a red-necked MAGA Yank.

[onetrack]

The Tweels are very expensive as compared to ordinary tyres, and they fill a niche market for off-road vehicles, forklifts and other industrial uses - but I don't think we're going to see them in widespread highway use, anytime soon.

[nomadpete]

10 hours ago, old man emu said:

Spacey, I thought you were British. A statement like that makes you sound like a red-necked MAGA Yank.

I think Spacey is referring to terminology. Regulations can refer to 'axle weight'

[old man emu]

1 hour ago, nomadpete said:

I think Spacey is referring to terminology. Regulations can refer to 'axle weight'

What is axle weight? Axle weight refers to the weight distributed over a single axle of a vehicle. Everyday thousands of heavy vehicles undergo weighing to ensure that the weight carried by each axle group does not exceed what the Regulations allow. Obviously, when the vehicles are weighed, the wheels are not taken off, so therefore the weight of the tyre and wheel rim are included in the weight carried by the axle group.

 

I must admit it might be taken that  I was being a bit nasty to Spacey, but I've been watching interviews with MAGA people and they are coming out with statements that indicate confusion about the topic about which they are being interviewed. What Spacey said about  no wheel weight pressing down on the axles is confused thinking.

[nomadpete]

1 hour ago, old man emu said:

What Spacey said about  no wheel weight pressing down on the axles is confused thinking.

That depends on your point of view.

I took it literally.

If you measured axle weight AT THE AXLE, Spacey is right.

Your official perspective on 'axle weight' is based on a misnomer. The regs are talking about what I call  'road contact weight per wheel'.

 

[onetrack]

No, you don't weigh what a vehicle "sits on". The definition of kerb weight is the total mass of an unladen vehicle, filled with necessary oils, coolant, and fuel that is required for operation. Wheels are needed for the vehicle to be able to operate.

A driver is not normally included in the weight, but the Europeans use an EC directive that states a driver must be included in the kerb weight.

When you get weighed by Transport Dept inspectors, the scales go under the tyres, not between the axles and wheels!

Wheels are actually quite heavy, unless they use alloy rims, in which case there's a major weight saving.

 

What Spacey is probably referring to is "axle loading capacity", which is a figure provided by all vehicle manufacturers for both front and rear axles in the specs - in which case, he is technically correct, in that wheels shouldn't count in "axle loading capacity, as the wheels are technically not loading up the axle directly.

But in vehicle operation, the wheel is not static, it's rotating, and bouncing up and down, and adding forces to the axle structure.

An out of balance wheel can add a lot of unnecessary forces acting on an axle or suspension. So the engineers include the wheels into the total mass of the vehicle.

 

Edited February 28 by onetrack
spellink......

[nomadpete]

We are agonising unnecessarily over semantics.

 

Obviously the wheels are part of the vehicle weight.

Equally obviously, the weight of the wheel adds to the weight on the road.

 

The terminology developed around 'axle loading' is often a simplified description that bureaucrats used in an effort to quantify road damage and the engineering requirements to design bridges, etc, to safely support vehicles .

 

Perhaps other terms would be more accurate.

 

But really, we all seem to know what we are talking about.

 

[nomadpete]

18 minutes ago, onetrack said:

No, you don't weigh what a vehicle "sits on".

Well last time I was at a weighbridge, I weighed the vehicle on 'what it sits on'. And it sat on it's tyres. And the number is called the GVM.

[facthunter]

space is technically correct but the force on the road is the mass of everything x "G" (Consider cresting a hill or a banked turn or operating on the moon. ).Nev

[old man emu]

If you simply consider the axle to be a length of material to which the vehicle is attached, then it is reasonable to say that there is a limit to the force (weight) that it can bear before failing (bending). That would be the "axle loading limit". 

35 minutes ago, nomadpete said:

The terminology developed around 'axle loading' is often a simplified description

So true. Structural Engineers will talk about stress and strain forces and things being in compression or tension when designing the axle and its means of attaching the vehicle's body. That's axle loading limit. Civil engineers will talk about Gross Vehicle Mass and axle loading when talking about pavement strength design.

 

Since the line of discussion about this new tyre design started off about the difference in weight between them and conventional tyre/wheel assemblies, perhaps we should accept the term "axle weight", as measured with the wheels of the vehicle standing on the scales.

[facthunter]

You can make your own airless tyre by stuffing grass or straw in  tightly and  being careful. I've only done it with the tailwheel. but If you are in the desert & running out of water, and the Indians are coming over the hill .  Nev

[old man emu]

Back in the day, friends of my sister had a Goggomobil. Yes, it was the Dart. Out on a drive one day they got a puncture. They packed the tyre with grass and were able to make it home.

 

Oh, such simpler times!

[onetrack]

You can also do away with wheels altogether, and just utilise a length of wood tied to the bodywork, and going under the axle! There's a few "only in 3rd world countries" videos showing that system in operation!

 

You wouldn't want to drive too far on grass stuffing, the heat buildup would more than likely set fire to it! I have done some innovative repairs to major wall damage, such as wiring (stitching) torn walls together.

 

When we were doing exploration lease gridding around '70-'72, cutting access lines with dozers, the peggers were using old Landrovers and 3-speed Landcruisers to drive straight through the bush to mark the gridlines.

They would invariably incur up to 10 or 20 stakes a day, which meant a lot of tyre changing work. They probably would have loved Tweels. As it was, they would buy used bald tyres and fit them, and pump them up to 45-50psi.

Their theory was that bald tyres pumped up hard, resisted stakes better - at the price of the ride, of course. The theory seemed to work O.K. for them, they ended up with less tyre stakes.

 

 

Edited February 29 by onetrack

[facthunter]

There's not  a lot of weight on a little plane wheel. I wouldn't do it if other options  were available. Normally you don't HAVE to get airborne.  Nev

[old man emu]

In reality, how far do the wheels of a little plane roll?