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18/05/2020
City roads or snowclad mountains; there’s a tire for everyone

Bus and truck tires 

 

City buses and trucks working in difficult conditions are the main recipients of the innovative products presented in recent months. For passenger transport, two new models are specifically designed for electrically driven vehicles, which are set to gain an increasing market share

Massimo Condolo

City buses, trucks operating in construction sites or icy roads: it is difficult to imagine vehicles with more diverse needs at first glance. Slippery roads, possible overloading, impacts with rocks, potholes and sharp edges resulting in abrasions and tearing, strong accelerations with high torque transmission are some of the problems that tires have to cope with in these areas. It is not because of this common need, however, that new winter products have been designed. Market forecasts (net of the severe effects of the coronavirus emergency) are linked to an expected renewal of the national fleet. As far as trucks, we are mainly talking about a generational turnover, as Euro 6 vehicles are still few and far between. The new class, however, is bound to affect the weight distribution, due to the considerable weight of the after-treatment systems. For buses, on the other hand, a real revolution is underway: within ten years, the market for city buses will be made up by at least 50% of electric models. Which not only weigh more because of the battery pack, but are capable of a much higher torque output than diesel. That is why the tire industry is reacting.

 

Electric drive specialists

Between December and February, two of the most important names among premium manufacturers presented specific models for battery-powered buses: Michelin and Prometeon. The French giant unveiled its X InCity Energy, with a load capacity increased to 8 tons on a single wheel axle (load index 152/148 J) compared to the 7.5 of the previous models, a greater capacity that translates into more seats, a long-standing problem for urban electric buses, while maintaining a normal size tire (275/70 R22.5). The X InCity Energy, built around a casing reinforced with special steels, offer low rolling resistance, 3PMSF marking, Regenion self-healing tread and low noise levels. The Italian-Chinese company, on the other hand, presented its MC:01 e-Urban under the Pirelli brand. Its focus is on energy efficiency (it is the only tire in the sector with B labelling for energy consumption) and is available as 275/70 R22.5 (load index 152/148 J) and 315/65 R22.5 (156/150 J, capacity of 8 t per axle). Rolling resistance benefits by a 10% reduction compared to the previous model and is marked M+S and 3PMSF. Increased load resistance has been addressed with an optimized sidewall and structure design, while the new tread geometry facilitates torque transmission; the profile protects against impacts and abrasions.

 

For long and short group journeys

Among new products for regional and long-distance buses, we find Continental and, once again, Prometeon. The Conti Coach Regio HA3 (all-positions) and HD3 (tractor) are destined for regional routes and motorways. Marked M+S and 3PMSF, they received a C rating for consumption and B for traction and have been awarded a C rating for consumption and B for wet grip. From the fourth quarter of 2020, HD will also be available as hot retreads Conti Re. The new Conti coach relies on a new compound in which a new rubber and a new carbon black filler have been used. On the HA the full depth sipes of the central part of the tread and the internal zig-zag grooves ensure cornering stability and little noise; the channels are designed to facilitate the expulsion of gravel. A multi-position model (FH:01) and a traction model (TH:01) also make up the new Pirelli Coach range, which focuses on traction and wet grip thanks to the new geometry of the grooves. Traction on snow has improved by 20% compared to previous models, while rolling resistance has decreased by 10%. They are available in sizes 295/780 R22.5 with load index 156/149M and 315/80 with load index 158/150L, corresponding to 8 and 8.5 t load capacity per axle. On the other hand, Giti focuses on city buses with its GAU 867 v.1, which boasts a casing optimised for urban use and 3PMSF marking. Compound, belt and sides help to minimize the risk of cuts and abrasions, while the wide tread pattern and new sipes in the central part of the tread improve traction; a tread wear indicator is placed on the side. The new model is available in sizes 11 R22.5, 275/70 R22.5 and 295/80 again for 22.5".

 

Made for tough terrain

Continental and Goodyear focused their efforts on those who have to face difficult conditions, such as operators engaged in construction sites and long winter routes. The German company's proposal starts from this sector, with the Hybrid Conti HT3 for trailers, the latest additions to the wide range with hybrid tread, which regenerates with consumption. Available in size 385/65 R22.5, they are suitable for regional or long distance routes and are available in five models. The HT3 WR Winter Regional is designed for use in areas ranging from the Alps to Scandinavia; it is thus marked 3PMSF and labelled C for consumption. The HT3 HL, which replaces the previous XL, is designed for heavy loads in the traffic and climate conditions of Western Europe; for use in difficult conditions such as those in North Africa, Russia and Turkey with the possibility of overloading, Continental offers the HT3 ED; The HT3 SR, instead, is suitable for slightly less severe tasks. The HT3, on the other hand, is designed for use on regional routes in Europe. Goodyear is adding the Heavy Duty series to the Omintrac range, which is designed for vehicles travelling on regional routes and construction sites such as concrete mixers and tippers. They are retreadable, regrooveable and covered by the warranty against accidental damage. Like the rest of the range, they rely on the Durashield under-tread protection belt, made of non-metallic material. They are available in the S-steer and D-traction versions, both with sizes 12 and 13 R22.5 and 315/80 R22.5.

 

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