A solution that allows drivers to continue driving while avoiding tire deflation after a puncture—and also not damage a wheel—is the run-flat. Run-flat tire technology is based on a reinforced sidewall that is self-supporting. In the case of a puncture, a sidewall insert prevents the sidewall from being crushed between the rim and road or from slipping off the rim (see Figure 4). A run-flat tire makes it possible to continue driving with zero air pressure for up to 95 miles with a maximum speed of 50 mph.
Run-Flat Tire Development
Tire development is always focused on designing for four key elements—pattern, contour, construction and compound (material). The majority of run-flat tire development is devoted to developing materials and construction. Engineers should develop a reinforced sidewall insert to support vehicle weight at high-speed driving with little compromise to other performance indicators. While the sidewall insert improves run-flat distance, it also increases vertical tire stiffness and, as a result, increases tire wear and reduces ride and comfort. Contour and pattern will be used to achieve other characteristics and optimize the overall performance.
Compounding/Material
The most important target conflict in run-flat tire development is ride and comfort. With the improvement in run-flat distance, the ride and comfort will be compromised. With a traditional compound insert on a run-flat tire, ride and comfort increase as the distance a run-flat can travel decreases. With newer compounding technology that improves the tradeoff between run-flat distance, ride and comfort, the goal for the future is to flatten as engineers are able to provide closer to optimal tire performance by maximizing mobility with little ride and comfort degradation.
Construction
When a flat occurs and a tire loses air, the sidewall insert should provide the vertical stiffness to avoid the tire’s collapse. At the same time, the bead and apex should be able to maintain proper seating with no- or low-inflation pressure. Optimizing sidewall insert thickness is key to providing the required run-flat distance with a minimal increase on vertical stiffness for better ride and comfort.
Apex height and shape, along with the size of the bead, are the other two important factors for maintaining proper seating and improving the run-flat tire target conflict.
Consumers’ love of motoring and the ever-present desire to go out, drive further and drive safer has created a need for continuous tire improvement and innovation—and the impact of run-flat tires through the years cannot be overstated. Over the years, engineers have relied on experience, new information, new materials and new construction techniques to better solve those problems. Today’s run-flat tires have far fewer compromises than the pioneering run-flats of 20-25 years ago. And knowing the scientific advancements made during that time, it’s easier to imagine a not-so-distant future in which run-flat tires could provide an optimal blend of comfort, performance, mileage, safety and peace of mind.
In the rubber mixing process, especially for internal mixers like a 110-liter volume mixer, the recommended fill ratio typically falls within the range of: Fill Ratio: 65% to 85%The fill factor or fill ratio is typically calculated as: Fill Ratio (%) = (Batch Weight / Mixer Chamber Volume) × (Specific Gravity of Compound) × 100 Example: Mixer Volume = 110 liters Target Fill Ratio = 75% Specific Gravity of Rubber Compound = ~1.2 So: Batch Weight = (110 × 0.75) / 1.2 ≈ 68.75 kg This means around 68–72 kg would be an optimal batch weight for a typical compound with SG ~1.2 in a 110 L mixer.
J J Murphy: Kerala’s Rubber Man “On a rainy day in Ooty, South India’s famous hill station, some nuns were walking along a road in the cold. Suddenly, a car stopped by and the gentleman driving it offered them a lift. He asked why they were not using a vehicle in such inclement weather. The nuns replied that their convent did not have one. The next day, a local dealer delivered a brand new Dodge car to the convent. The astonished nuns thanked the donor. They also told him they could not keep the vehicle because there was no money to engage a driver or to buy petrol. The gentleman assigned a driver on his payroll to the convent. He also instructed a petrol bunk to forward the convent’s bills to his office.” This is an anecdote about a man you’ve probably never heard of – an Irishman named John Joseph Murphy (1872 – 1957). But in the rubber plantations of Kerala, Murphy is a legend. A planter who arrived in India at a very young age, it was Murphy who set up India’s first commercially su...
ReTyre: Tyres Can Now Be Simply Zipped On ReTyre claims that they have created the world's first modular tyre system. It is quite easy to change the suspension setting, tyre pressure considering the different riding conditions and even the riding kit but changing the tyre tread has not been an easy task like the rest. Basically, there is a base tyre, ReTyre and a slick road tyre that can be used on tarmac surfaces but it also has zips on the the sidewall, above the rim. The manufacturer claims that additional skins with different tread pattern covers the Retyre with the help of the zip on the sidewall. There are 4 different skins for different terrains such as the Winter Traveller, Trail Rider, Gravel Chaser, Ice Rider. The best part is that the skins can be fitted without removing the wheel and can be easily stored too. The question which comes into everybody's mind is whether the zippers can withstand the torture from riding on different terrains, and the answer to it is ...
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