Designed for extreme driving
Noise levels, braking efficiency on asphalt and fuel consumption have been sacrificed on the altar of maximum grip. Unlabelled tires, zero compromise, pure off-road.
Tires entrusted with extreme mobility, when natural ground conditions require maximum grip, in order to be able to move forward with a 4x4 vehicle ensuring sufficient grip in the presence of mud, debris, rock or wet foliage.
Professional operators who have to drive off-road and on some of the most impervious routes, as well as enthusiasts who try their hand in extreme natural conditions, either for competition or outdoor excursions, can rely on a category of tires perfectly defined by the acronym POR - Professional Off Road - which refers to a tire designed specifically for natural terrain. This means specialized tires able to deliver uncompromising performance in extreme conditions, at the expense of driving precision on normal roads, fuel economy and comfort, in favour of maximum off-road grip. Easily recognizable for their aggressive design, their reinforced radial structure, especially on the sidewalls, even though in some cases, their conventional cross-ply structure, extremely spaced tread, with large tread blocks found also close to the shoulder, is also a bit of a giveaway, as well as, of course, the POR marking featuring prominently on the shoulder next to the tire measures. Usually these professional mud terrain tires have lower speed codes than traditional tires as well as the most common all terrain tires found on the market, precisely because of their reduced efficiency on tar roads and an energy label that cannot be classified in any rating. Therefore, though legally permitted on the road, the driver needs to be aware of the speed limits. Since these tires represent a niche within a niche, the measures available are decidedly limited and mainly focused on a restricted number of off-road vehicles. Without considering tuned-up or competition vehicles, for which, road use is often precluded. However, this is an entirely different matter.
Here is a brief overview of some of the most popular products on the national market.
That is, when the exception confirms the rule. A rule is always to equip each vehicle with tires corresponding to the speed codes shown in the registration book, which, depending the kind of equipment may vary downwards, it being understood that, the tire dimensions must always correspond to those approved for that specific vehicle.
The European Commission Regulation no. 458/2011 dated May 12, 2011, in paragraph 4.2.3, quotes:
“In the case of vehicles equipped with professional off-road tires with the POR marking. However, if the maximum vehicle design speed is greater than the speed corresponding to the lowest speed category symbol of the fitted special use tires, a maximum speed warning label, specifying the lowest value of the maximum speed capability of the fitted special use tires, shall be displayed inside the vehicle in a prominent position readily and permanently visible to the driver”.
This, because it is assumed that vehicles equipped with these special tires are used in extreme conditions where parameters such as top speed, braking distances on tar, noise levels and fuel consumption, for example, take second place to pure grip performance on soft ground. For this reason, therefore, as an exception to the speed code, below which no one should go, the adoption of a product marked POR must necessarily be accompanied by the application, on the dashboard, in a position clearly visible to the driver, of a warning label bearing the reduced speed limits. These must necessarily be adhered to so as not to jeopardize a set of tires designed not to ensure the best speed performance on tar roads, thus avoiding, in case of a control by the police, to incur in sanctions or a forced stoppage of the vehicle.
BFGOODRICH MUD TERRAIN T/A KM3
BFGoodrich's Mud Terrain, a brand of the Michelin group, in its fifth and most recent version marked KM3 is one of the best-known off-road specialist products. The new tread improves its traction and climbing capability, besides significantly increasing its lifespan thanks also to a reinforced structure with CoreGard Max technology, tested in off-road competitions, greater thickness in the sidewalls and a Krawl-Tek compound that provides superior grip on rocks and smooth surfaces. In spite of its limited distribution, the range offered is particularly wide, about fifty references, all branded Professional Off-Road with speed code Q (up to 160 km/h), available both in inches and metric sizes, covering a range between 32x10 R14 and 39x13.50 R17, and between 215/75 R15 and 305/55 R20 respectively.
COOPER DISCOVERER STT PRO
The American school of off-road racing expresses itself with Cooper's Discoverer STT Pro, the most aggressive tread offered by the brand and developed thanks to the experience gained in off-road competitions. A structure composed of two polyester radial plies overlapped by a third layer in Armor-Tek, provides adequate strength and flexibility, while the arrangement of the tread blocks provides a central band with differentiated blocks in sequence 3-2, improving stability, grip and a surprisingly reduced noise level. The deep V-shaped grooves offer grip and self-cleaning capacity, preventing the retention of gravel and mud. Here too, the range available is particularly wide, over 30 sizes in Q speed code covering a wide range of users, for applications between 30x9.50 R15 and up to the extreme 35x12.50 R22.
CST TIRES LAND DRAGON CL-18
An Asian product by fast growing CST Tires, the "forest" type tread of the CL-18, designed to bite deeply into soft ground, has massive convex shaped shoulder blocks widely spaced between them, ensuring effective grip even in muddy ground or even marshes. The high full/empty ratio and the marked depth of the grooves, with a central band of sturdy blocks, allow to get quickly rid of any unwanted debris, while the reinforcement plies on the sides reduce the risk of cuts and punctures close to the shoulder. Seven sizes, so far, are found in the price list, all in inches and concentrated on the most common applications, with speed code K (up to 110 km/h). They come in a range between 33x11.50 R15 and 36x12.50 R16.
FALKEN WILDPEACK M/T
The most aggressive off-road tire by Falken - brand of the Sumitomo group -, which bears the M+S as well as POR markings, features a rather typical design for this product range, particularly effective on inconsistent or soft terrain. The symmetrical pattern of the tread blocks is uneven and extends over the shoulder to improve traction through furrows found on the ground. It is designed to provide traction on soft ground and, together with the grooves half way down the tread blocks, facilitate the drainage of mud and water. Edges at the top of the sidewall protect the tire against sharp rocks. Eight sizes, between 15 and 17 inches, series from 70 to 85, with speed code Q, make up a selected dimensional offer suitable for the most specialized 4x4 vehicles.
GENERAL TIRE GRABBER X3
American brand specialized in 4x4s, part of the German Continental group for 35 years now, General Tire expresses its maximum off-road performance with the Grabber X3. An aggressive design with a high full/empty ratio, an increased number of edges to maximize grip on any natural surface and X-shaped central blocks, features grooves that reach all the way to the sidewalls, to facilitate the expulsion of debris, with protective rubber on the bottom of the grooves to reduce the possibility of punctures caused by stones. As many as 35 sizes are available, all in Q speed code, between 215/75 R15 and 35x12.50 R20.
GOODYEAR WRANGLER DURATRAC
Still from the States, a product destined for maximum off-road and snow traction; the DuraTrac series, made using Goodyear's Tractive Groove Technology, which allows more traction in the worst grip conditions. The central band dominated by sloping blocks, with zigzag micro grooves for better wet grip, is combined large blocks on the sidewalls and sharp-edged to provide high off-road traction. Distinguished by the winter snowflake symbol, the DuraTrac series can also be ordered in a studded version. Seven sizes are available catering for a wide number of off-road and pick up vehicles, all in Q speed code and between 31x10.50 R15 and 315/70 R17.
HANKOOK DYNAPRO MT RT03
The mud terrain design by the Korean company, called RT03, provides a radial structure with reinforced nylon top plies, symmetrical V-shaped blocks, sharp edges to increase the effect of grip and uneven side edging to improve off-road traction. Very wide transversal grooves and a pattern designed to facilitate the ejection of stones and mud, with anti-puncture protections on the bottom of the grooves, guarantee adequate grip and dirt removal in any condition. Characterized by low noise levels, the dimensional range currently available consists of thirteen references, between 31x10.50 R15 and 315/70 R17, with speed code Q.
MAXXIS TREPADOR M8060
These are among the most specialized tires on the market, among the few to offer traditional cross-ply technology (Bias) instead of radials, so as to benefit from maximum flexibility and support on soft ground, able to run even with low internal pressure. Also available, in the same series, is the radial version, which is more rigid for a more stable behaviour at a sustained pace. Both feature an extremely aggressive directional design, 100% off-road, with “curvy” grooves suitable for the best traction on soft terrain and large tread blocks all along the side. Two compounds are offered, a normal one and the soft "sticky", for maximum grip. The sizes available on the price list for the cross-ply version amount to not even a dozen and very selected, ranging between 35x12.50 -15 and 35x12.50 -20, with speed codes K or L. Instead, the number of sizes available for the radials are about 15, ranging between 235/75 R15 and 40x15.50 R22, all in speed code Q.
MAXXIS CREEPY CRAWLER M8090
Even more extreme and intended almost exclusively for racing, even if POR approved and therefore admitted to road traffic, designed for the typically American rock crawling competitions, but also suitable for moving on particularly difficult terrain, the Creepy Crawler series by Maxxis feature a radial structure to provide a full bite pattern, wide grooves interspersed by massive longitudinal blocks, extending over the entire sidewall of the tire. As for the Trepador, there are two compound options available, traditional or "sticky". Here too, the sizes available amount to ten, between 35x12.50 R15 and 40x13.50 R17, always in K or L code.
NEXEN ROADIAN MTX
A special corrugated block design, with patented variable inclination technology, make Nexen's Roadian MTXs easily recognizable. Low noise and effective grip performance on the most difficult terrains make the Rodian a true off-road champion. Sturdy and durable, the lateral reinforcement improves performance even on snow and mud, with high self-cleaning power from mud, stones and snow collected in the grooves. The size range, consisting of about fifteen references, all in Q speed code, focuses on 17-inch sizes, from 235/80 R17 to 305/65 R17, with only five sizes in inches, between 33x12.50 R15 and 33x12.50 R20.
TOYO OPEN COUNTRY M/T
Toyo’s Mud Terrain boasts a rather unique design, featuring a central band with hook-shaped blocks with sipes to facilitate grip in wet conditions, large drainage grooves with serrations at the bottom of the shoulder to facilitate the dispersion of any unwanted material collected, and a strong radial three-layer polyester structure to ensure adequate load capacity. There are twenty sizes available, from 31x10.50 R15 to 37x13.50 R24.
YOKOHAMA GEOLANDAR M/T G003
Yokohama has two offers in the Professional Off-road sector, testifying to the sporty and extreme vocation of the dynamic Japanese brand. With the Mud Terrain G003, Yokohama expands its Geolandar range, dedicated to utility sports and off-road 4x4s, with an aggressive design suitable for softer terrains. The tread features wide sequential grooves with lateral shoulder top reinforced against the risk of abrasions and punctures. A catalogue consisting of thirty sizes, all with speed code Q, includes treads from 15 to 20 inches, between 31x10.50 R15 and 305/55 R20.
YOKOHAMA GEOLANDAR X-M/T G005
Even more specialised, the Geolandar X-M/T G005 is the latest off-road tire dedicated to those who require maximum traction on natural terrains. This is an extreme tread design - hence the abbreviation X - particularly aggressive and resistant, with a three-ply nylon casing reinforced on the sidewall and a uniquely high full/empty ratio, with irregularly placed blocks and drainage sipes, which extend generously over the shoulder, favouring lateral grip. Launched last year, at the current range available has about fifteen references, going from 35x12.50 R17 up to 40x15.50 R24, probably the most popular size currently available with POR classification.