Tires made of polyurethane elastomers
Dr. Tech. Science S.A. Lyubartovich,
Ph.D. chem. Sciences L.A. Shumanov, Ph.D. tech. Sciences I.V. Veseloye, NIISHP, LLC NPP "Polyurethane"
Tires are the most common and complex type of elastic products for technical purposes, being an important and critical part of cars, aircraft, military and agricultural equipment, bicycles, motorcycles, and others. Vehicle. Tire production volumes in the Russian Federation have been steadily increasing over the past 10 years to 8-10% per year. Currently, about 42 million tires are produced in the Russian Federation per year (excluding massive and other non-pneumatic tires).
The tire is a knowledge-intensive, structurally complex product, since it is subject to a wide range of conflicting technical requirements: mechanical strength, structural rigidity combined with good shock-absorbing ability, high rolling speed and low heat generation, low rolling resistance and high wear resistance combined with good grip and low braking distance, etc. Implementation of an acceptable compromise of tire properties requires more complex design and the use of complex resource-intensive technologies.
In this regard, polyurethane elastomers, which have a unique set of technical and technological properties (unattainable in traditional rubber), prompted tire manufacturers, in particular NIISHP, to begin work on the creation and implementation of polyurethane tires immediately after the emergence of the polyurethane raw material base in the mid-20th century.
The introduction began with massive tires, where high elastic-strength properties combined with high elasticity and wear resistance of polyurethane made it possible to increase load capacity up to 3-6 times and service life up to 10 times compared to a rubber tire of the same size. Reducing the permissible diameter and width of the wheel when using a polyurethane tire makes it possible to increase the maneuverability of outdoor vehicles, and lower rolling resistance helps reduce the frequency of recharging batteries of electric vehicles and increases the weight of goods transported on hand trucks.
NIISHP together with LLC NPP Polyurethane have developed a wide range of massive tires made of polyurethane elastomers based on simple and polyesters with a hardness from 55 to 95 conventional units. units according to Shore A for trackless and rail transport, including rollers for subway escalators, disk-type stabilizing wheels for monorail rolling stock, massive tires for roller coasters, tires for internal transport, loaders and carts for various purposes, wheelchairs, rollers, rollers and asphalt shoes for tracked vehicles, etc.
Self-supporting tires (including “tunnel”, “cushion” or “elastic” type) - differ from a conventional solid tire by the presence in the polyurethane mass between the tread and landing parts of closed circumferential cavities or support ribs evenly distributed around the circumference or open cavities with axial, circumferential and/or radial orientation. These supporting ribs or recesses can have different configurations, for example, have the form of through cylindrical, conical, wedge-shaped or other holes, form a network of partitions, radial or involute ribs.
The latter includes, for example, a polyurethane spare wheel from Uniroyal. A spare wheel weighs 3-4 times less than a regular tire and takes up less space in the trunk of a car, while having a range of up to 4,800 km at speeds of up to 125 km/h.
Specialists from the American Michelin Research Center are working to create a self-supporting polyurethane tire combined with a disk, the so-called Twel wheels (Tire + Wheel, tire + disk). In these tires, the role of a shock-absorbing element is not played by air, but by elastic polyurethane spokes connecting the tread and the disk. According to the developers, the main advantage of such tires is the ability to independently change their radial and lateral stiffness.
Self-supporting tires include tires with the so-called “tunnel cushion”, which have a “V”-shaped profile. We have developed tunnel-type tires for drive and load-bearing wheels of wheelchairs 37-533, 37-540 and 47-110, which fully meet customer requirements: they do not require air inflation, have good shock-absorbing properties, do not leave marks on the floor, have low rolling resistance, high wear resistance and attractive colouring.
Elastic polyurethane inserts and fillers are used in safety, puncture-resistant tires. Elastic inserts in the form of polyurethane self-supporting support rings are used in safety passenger wheels of the PAX type, developed by Michelin together with the chemical company DOW with the participation of Goodyear and Pirelli. In PAX tires, in case of punctures and complete loss of pressure, the polyurethane insert allows the driver to maintain control over the car and drive up to 200 km at a speed of 80 km/h. The polyurethane support ring of a self-supporting structure has a mass 2 times less than the rubber support ring of a similar tire. In tires operating at relatively low speeds, low-modulus polyurethane fillers such as Thayerfil or foamed polyurethanes are successfully used instead of air. The mixture of initial filler components is pumped into the tire cavity through a valve at a pressure corresponding to the operating air pressure in the tire.
Atmospheric pressure tires have a configuration similar to a pneumatic tire, but operate at zero excess pressure. We tested atmospheric pressure polyurethane tires for the drive wheels of wheelchairs, strollers 37-533, agricultural tires 5.00-10 and tires 34-286 for the children's bicycle "Sparite-ZM". In 34-286 tire to ensure a tight and secure fit
The rim used a closed profile design with a detachable base.
Polyurethane pneumatic tires are a unique, without exaggeration, the most complex product made from polyurethane elastomer. We worked on its creation for about 30 years, theoretically substantiating, experimentally working out and testing dozens of design and recipe-technological options.
Work began with a cast cordless tire made of one and then two polyurethane elastomers with different physical and mechanical properties. Having not achieved the required result, we began to work on various options for reinforcing the tire breaker in the circumferential and diagonal directions, and then the frame in the radial direction. As a result of this work, pneumatic polyurethane passenger and agricultural tires of radial design were created, which successfully passed bench laboratory-road (laboratory-field) and operational tests.
Similar work was carried out abroad, in particular by LIM Holding SA, Luxembourg, (formerly Polyair), whose shares are owned by Daimler-Benz AG, Stuttgart. Germany, B.F. Goodrich, Akron, USA. In 2001, information appeared that one of the world leaders in tire production, Goodyear, together with Ameritainer Corp. have begun developing polyurethane car tires, which they consider as a possible promising alternative to existing tires.
The technological concept for the production of polyurethane pneumatic tires is fundamentally different from the traditional concept of tire production and is based on the following principles:
- tire production is concentrated in relatively small capacity (up to 100 thousand tires per year) machine complexes on a modular basis with a full technological cycle for tire production, which are highly mobile in terms of changing the tire design and changing the production program;
- formation of a rubber-cord structure of a tire from parts of a ring configuration by aggregation (molding or sequential application) of elastic and reinforcing tire parts on a rigid sector toroidal mandrel;
- use of precision methods of liquid reaction molding in rigid vacuum forming equipment for the production of elastic elements of the tire;
- reinforcement of the carcass and belt of tires using automated machine winding methods of a single cord thread (or strands of threads) without the formation of circumferential joint zones with defects in the cord structure (overlaps, vacuums, folds);
- use of direct technological flows (without intermediate warehouses) with a compact arrangement of equipment and a minimum length of transport systems at the main stages of tire production.
Considering that this technology is based on the processes of winding and casting, it can be conventionally called winding and casting technology.
Thanks to the winding-molding technology, which ensures the production of precision twin tires with good geometric and force heterogeneity and a unique set of physical and mechanical properties, polyurethane passenger tires have the following advantages (compared to modern pneumatic tires and traditional technology):
. reduction in tire weight by 15-20% and rolling resistance by up to 30%, which determines a reduction in fuel consumption during vehicle operation by up to 5-8%;
. increasing wear resistance by 30-50% and tire uniformity, which helps to increase their service life;
. improving driving comfort, increasing speed characteristics and tire safety;
. wide range of tire colors, which allows you to choose the color of the tires
match the body color, increasing the level of car design;
. reducing the energy intensity of production by 2-3 times and its labor intensity by 1.5-2.0 times;
. reduction by 2-3 times of production space, loading and unloading and transport operations, a significant reduction in the range of equipment and its metal consumption;
. elimination of intermediate warehouses of tire blanks and parts;
. increasing the agility of tire production, the ability to flexibly respond to changes in consumer market demand;
. low-waste technology, the possibility of reusing the elastomer used in tire production;
. reducing the negative environmental consequences of tire production and operation (reducing harmful air emissions from cars and tire factories, eliminating wastewater, reducing soil contamination, etc.).
Agricultural polyurethane tires 240/70-508Р have successfully passed bench, laboratory, field and operational tests. These tests have shown that polyurethane tires, having 20% less weight than their traditional counterpart, have a 1.7 times greater service life, assessed when running on a drum with clumps, while oligomeric tires have better grip properties (dry and wet). coating) and indicators of stability and controllability.
The main technical solutions for pneumatic tires, materials, technology and equipment have been experimentally tested on more than 1000 tires and patented. For the industrial implementation of the production of pneumatic tires from polyurethane raw materials, a strategic investor is required.
Road grip is an important and necessary characteristic of a bicycle that makes your riding more comfortable and reliable.
We invite you to familiarize yourself with a wide range of bicycle tires of different types and for different conditions! Bicycle tires are of great importance for the safety of cycling, as well as their comfort. Their choice is a priority for professional cyclists and lovers of leisurely city riding. How reliably the bike’s wheel will be protected depends on the quality and characteristics of the rubber. Particular attention should be paid to the fact that the type of bicycle tires depends on the time of year. Of course, it is different for each type of bicycle. So, in order to buy bicycle tires accurately, it is worth understanding their types.
How to choose the right bicycle tires
Bicycle tires vary in density and quality of rubber, size, and pattern on the tread (tire surface). When choosing a suitable model, you should pay attention to the type of driving, preferred routes and weather conditions. So, bicycle tires come in the following types: - Studded. They are tires with a tread on which special studs of a certain size are located. Designed for driving in areas with a lot of dirt, as they knock it off the wheel.
- Gravel. Special tires designed for mountain bikes. Their surface provides a tight grip on gravel and allows you to walk through muddy areas.
- Winter. It features a compacted tread that provides traction on ice, snow and mud. If you are planning “rides” in the winter, buying winter tires for your bike is a must!
- Slicks. These tires are characterized by the absence of tread. The model is characterized by the presence of drainage channels and is designed for travel on asphalt and racing tracks. Suitable for high-speed sports bikes.
- Half-slicks. They are characterized by the presence of tread only at the edges of the bicycle tire. Reliably protect the wheel and inner tube of the bicycle, suitable for long trips and travel. Driving is possible on dirt roads and off-road, but only in good weather conditions.
It is important to understand that purchasing tires is important both after they are worn out and for stock.
Where to buy quality tires
If you need to buy a tire for a bicycle, models from branded manufacturers are collected in the catalog of the “YourBicycle” online store. Why is it worth ordering tires from us? Purchasing in a store has the following advantages:
A wide range of. Over 600 models of the types listed above, from manufacturers like Continental, Maxxis, Kenda and others.
- Loyal price. Direct cooperation with manufacturers allows us to create loyal pricing.
- Reception and processing of applications in a short time, followed by prompt delivery.
- Competent online consultants who will help you choose.
- Possibility of purchasing tires for a bicycle at a discount.
Cooperation with the online store “YourBicycle” is the prospect of purchasing high-quality, indestructible, so to speak, rubber that can protect the bike for a long time.
This question probably came up at least once in the minds of any skater who was busy replacing/sealing the tube after another puncture. In general, if you inject drugs regularly, I advise you to read my article about, where this issue is practically resolved.
How cool it would be - you could even drive on nails and glass. I remember children's three-wheeled bicycles - after all, they rode on tires made of solid rubber, so why do we need these tubes?
There are three main complaints about solid rubber tires: heavy weight, rolling resistance and lack of proper shock absorption; in addition, such a tire will not adhere well to the rim and can fall off if a strong lateral load occurs. The combination of these factors makes such a tire absolutely inapplicable in real life.
Nowadays, many ordinary pneumatic bicycle tires with very serious puncture protection are produced; take, for example, the same Schwalbian marathon on which travelers ride around the world. There would seem to be no point in returning to tires made from a single piece of rubber.
Well forgotten old
However, this idea haunts some manufacturers, for example, the Korean Tannus Tires. At the heart of their development is a polymer called Aither, which they say allows the solid rubber tire to have ride characteristics almost as good as a conventional pneumatic tire.
Firstly, the weight of a 23mm solid tire is within reasonable limits - 380 grams. Not bad, a puncture-resistant pneumatic tire of this size is unlikely to weigh much less, taking into account the tube and rim tape.
Secondly, a tire made from a tricky polymer rolls only 8 percent worse than its pneumatic counterpart (according to the manufacturer’s measurements).
Thirdly, everything seems to be fine with shock absorption: there are two versions that have elasticity equivalent to 90 and 110 PSI on pneumatic tires. Probably, the polymer is very “delicate”, because the manufacturer claims a resource of only about 15 thousand kilometers, although it would seem that a solid piece of rubber should last almost forever.
They are asking quite reasonable money for the tires - 99 pounds per pair at the British representative office of Tannus Tires, at least the price is comparable to a pair of Marathons.
So far, only the 23mm by 28-inch version is being produced - the target audience of these tires is very wide: hipsters on fixed bikes, bike couriers, travelers and city bikers. In short, everyone who drives on asphalt can put up with a little more weight and a little worse rolling ability for the sake of a worry-free ride in terms of punctures.
There are some doubts about the rubber's resistance to lateral loads; it is not entirely clear how it holds up in turns and does not spin when braking. But the manufacturer recommends its tires primarily to owners of fixed-wheel drive vehicles, and there everything is in order with lateral loads - remember about braking with skids.
In my opinion, the undertaking is more than interesting; it’s high time to break the mold and bring new/forgotten ideas to the market. What do you say, do solid rubber tires in a modern design have a right to life?
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Many car enthusiasts have already heard about new airless tires, and if they haven’t heard of them, they’ve definitely secretly dreamed of them. After all, what is the main principle of operation of an ordinary car tire? Air under pressure is “locked” inside a rubber volume, which is subjected to a wide variety of tests by the grateful external environment: sharp stones and nails, curbs with protruding pieces of iron... in the end, people who just like to puncture tires still haven’t died out either. What happens if you remove the same air from the equation of ordinary tires (it doesn’t matter whether you have tubed or tubeless ones)? With less pressure than required, fuel consumption will increase, the car’s behavior on the road will worsen... If there is a complete lack of pressure, we simply won’t go far. Let's see how it appeared, how it is developing and what are the latest developments in the industry of creating airless tires. And if all this happens at a dangerous time for a person, then the price of “air” will be at least one life.
What are “airless tires”?
First, a little history. The Pentagon was the first to officially talk about creating an airless tire system. Of course, exclusively for military purposes: armoring the rubber of military equipment did not always solve everyday dangers and all possible situations. And when the military leadership of not the poorest country allocates funds for this or an idea, thoughts are found. The first developments were immediately used on the Humvee military transport, where both the numerous advantages of the new technology and its few disadvantages were immediately identified.
So, airless tires are a hollow structure in which rubber walls most often take on the function of air.
Airless tire design
In appearance, if new tires are closed (with side walls), then it is difficult to distinguish them from ordinary “air” tires. Adding to the previous paragraph: today there are two main designs of such tires:
- some are filled with special fiberglass
- the latter compensate for the lack of air by the presence of polyurethane spokes.
The design ultimately seems very simple: the edge of the tire is a tension clamp, the middle is a classic hub, to which polyurethane spokes are attached strictly in a certain sequence. Each modern manufacturer has its own “drawing”, each of them will demonstrate its advantages and disadvantages.
Application of airless rubber
Needless to say, a simple but effective design that will forever make you forget about punctures or inappropriate pressure quickly outgrew the framework of the military industry and rushed “to civilian life”? Unfortunately, developments in this industry are still actively underway; more or less production copies have so far found their use on lightly loaded vehicles such as lawn mowers, scooters or golf carts. In the industrial sector, airless rubber is used in excavators and loaders, and in personal transport they are now used in some places in wheelchairs and bicycles.
Advantages and disadvantages of tires without air
As already mentioned, the new design, which is currently being actively developed, has both undeniable advantages and disadvantages that have not yet been corrected. To begin with, it is worth pointing out the main advantages of tires without air:
- The wheel is capable of changing shape depending on the unevenness it passes - holes and bumps are literally “swallowed”
- The wheel is fully functional as long as at least 70% of its elements are in place (a big stone in the garden of pneumatic tires)
- There is absolutely no need to check the pressure, and where there is no pressure, there is also no possibility of bursting
- The weight of airless rubber is significantly less than that of its classic counterpart. The complete absence of the need for disks (steel, cast, forged, etc.) reduces the unsprung weight, which also leads to positive driving effects.
- As a consequence of point 3, there is no need to carry additional tools with you such as a jack, pump, keys... (however, the latter will not harm in any case)
- The consequence of points 3 and 5 is a reduction in transported weight and, as a result, a reduction in fuel consumption
- Prices for airless tires (when they fully appear on the shelves) are unlikely to exceed pneumatic analogues (not counting the first time when the main BOOM goes)
- In the future, installation of airless tires will be available on absolutely any car - from the ancient “penny” to the most modern SUVs.
- The current promising development of airless rubber is the ability to quickly change a worn-out (or unsuitable for the current road situation) top layer that is in direct contact with the road. All you have to do is install a “racing” profile, secure it with special bolts, and off you go. We need to go to the mountains - I attached a high-profile “skin” to the same polyurethane base.
As you can see, the new technology has a lot of advantages. The fly in the ointment is worth noting the following points:
- As was said, the safe speed limit for now is 80 km/h
- Some designs also exhibit excessive noise and heating during prolonged high-speed operation.
- The load capacity of such rubber... The technology is still imperfect
- The rigidity of the structure is not adjustable in any way. There is no option to lower the pressure and drive on sand.
Prices for tires without air
The first “civilian” airless tires were patented in 2005 Michelin, calling his creation Tweel (tire + wheel). Using them on the same special equipment, scooters and wheelchairs, the design is still not finalized for high speeds. Structurally, Tweel is a system of one-piece internal hubs attached to the axle shaft. Around them are polyurethane knitting needles connected in a certain sequence. A tension collar runs through the spokes to form the outer edge of the tire (the part that contacts the road).
The company became a competitor for Michelin Polaris, demonstrating his vision of the “tires of the future.” Structurally, they are quite similar, but Polaris made one improvement: the spokes were replaced with a honeycomb system like a beehive. Plus, we used other composite materials that we developed ourselves. The advantages of the new product have become noticeable: the resulting cells, depending on the speed of movement, exhibit different rigidity parameters: sometimes they are rigid, sometimes they are flexible, and as a result, the shape of the wheel is better maintained, coupled with good absorption of irregularities.
Bridgestone airless tires showed the world their “pattern”: now the profile has spokes that twist in both directions, thanks to which the tire becomes more elastic. Bridgestone approached the choice of raw materials quite “green” and proposed creating new tires from recycling old rubber. However, practice has shown the possibility of using such a design only in golf carts: the maximum speed is no longer limited to 80, but to 64 km/h, and the load capacity of one wheel is only 150 kg.
Airless tires I-Flex (Hankook) took an unexpected turn in this industry. The Korean company has created tires in which the tire and rim are one whole. 95% of I-Flex is made from recycled materials. They were shown for the first time at the 2013 Frankfurt Auto Show, made by I-Flex, they were in size 14″ and had a rather original design that attracted visitors.
Nowadays, similar airless tires are installed on small Volkswagen Up models.
The latest news in the small world of airless rubber was the release of the fifth generation Hankook I-Flex tires, in which the engineers managed to cross the “80-kilometer barrier.” Based on the results of a series of tests, it was revealed that the new design, together with new recyclable materials (“greens” rejoice), now rests on the speed limit of 130 km/h. An additional advantage of the new product is the ability to install the new Hankook I-Flex-V on a standard rim.
So far, airless tires are at the stage of improvements and the introduction of new ideas; the initial market is the USA. On the other hand, this technology will come to Russia much more advanced and refined, with a reduced starting price and high quality. It makes sense to wait.
A flat tire can ruin even the most fun bike ride. How to avoid this? Of course, you can always carry a spare inner tube, a set of mounts and a pump, or a bicycle first aid kit with you to quickly patch up a puncture. This state of affairs suits only tire manufacturers and sellers. For those who are tired of dealing with punctured tires, the market offers airless tires that cannot be punctured. Let's talk about them.
Why no air?
The idea of an airless tire is not new. And some may even remember that airless tires appeared before pneumatic ones. As soon as Dunlop began producing pneumatic tires, humanity immediately forgot about airless tires. About two minutes. It turned out that there are a lot of problems with pneumatic tires: they are unreliable, difficult to manufacture, do not decompose, and are difficult to recycle. Thus, reliable and durable tires without air have become a fixed idea for many inventors who have been trying for a hundred years to create such a prototype so that it does not weigh a ton, does not fly off the rims in turns, or at least does not fall apart at speed.
So why return to this idea that has already seemingly sunk into oblivion? Progress does not stand still, and modern materials and technologies allow manufacturers to work in this direction. Back in 2005, Michelin patented Tweel - airless tires for cars. Since then, Polaris, Bridgestone and Hankook have introduced their own versions of these tires. So far, the spread in characteristics is quite large, and the main disadvantages of these solutions remain the low maximum speed of 80 km/h for a car and low load capacity. But there are many advantages: the lighter weight of such rubber, increased service life, increased cross-country ability, and, of course, such a tire will not fail due to a puncture.
Following the manufacturers of automobile tires, cyclists also caught up. At the moment, two manufacturers have presented their versions of airless tires: the English company Tannus and the American startup Nexo. These manufacturers took a completely different route: they created a solid tire, without any cavities at all. And both companies have already announced nothing less than a revolution in the production of bicycle tires. Let's take a closer look at their developments.
Tannus rubber is made from a foamed polymer called Aither. At first glance, it looks similar to the material from which soles for running shoes are made, but, according to the manufacturer itself, it is a completely different polymer. The company even managed to improve the composition of the polymer and introduced a more elastic version of Aither 1.1, which has better grip on the road. Tannus tires are compatible with most modern wheels, and this is a definite plus. Another advantage was the weight - only 380 grams. Tannus Tires has one drawback - the price. They cost at least twice as much as “top” competitors. Whether a more reliable and durable tire is worth that kind of money is up to you to decide. By the way, the declared service life is 6,000 miles, or almost 10,000 kilometers. Enough to travel from Moscow to Vladivostok. And you don’t have to take a spare chamber with a pump.
Nexo gave birth to two developments: Nexo Tire and Ever Tire. These tires can be ordered directly from Kickstarter and are scheduled to begin shipping this month. Let's start with Nexo.
Nexo Tire has the same concept as Tannus Tire, but there are a few differences. The material for Nexo was also a polymer called Nexell, only this time it was not foamed, but liquid. Let's not bore you with discussions about differences in molecular structures, but let's get straight to the numbers. These tires weigh 710 grams. The declared maximum mileage is 5000 kilometers. Prices start at $140 for two sets of tires. The main design difference from Tannus here is the proprietary T-Bolt fastening system. It consists of many plastic T-shaped fasteners that hold the tire to the rim. You can install these tires yourself, since the kit includes all the necessary tools.
The second option that Nexo offers is Ever Tires. These tires are more like the designs presented by car tire manufacturers, and you will definitely become the center of attention on all the rides. There are also some nuances: these tires are not intended for off-road speed records, but for casual riding in parks or commuting to work. Their declared maximum mileage is already 8,000 kilometers. A 26” set will cost $96. These tires require special rims which are included in the price.
Let's summarize.
So, functional airless bicycle tires are already a reality. So is it worth running to the store to get them? Not so simple. All the tires we reviewed above are designed for city and road bikes. Initially, they were created with an eye on people who ride a bicycle to work. Wear resistance and puncture protection are very important here. So, if a bicycle is a replacement for public transport for you, take a closer look. It might be worth spending once on a set of expensive Tannus that will most likely outlive your bike.
There is no production for airless tires yet, and although manufacturers say they are working on it, so far pneumatic tires are ahead of airless tires in all respects when driving on non-smooth asphalt. Therefore, if you prefer freeride or bike trips, you will still have to carry a pump, a tube, and a bike first aid kit with you.