Continuous track Continuous track , also called tank tread or caterpillar track , is a system of vehicle propulsion in which a continuous band of treads is driven by two or more wheels . This band is typically made of modular steel plates in the case of military vehicles , or rubber reinforced with steel wires in the case of lighter agricultural or construction vehicles . The large surface area of the tracks distributes the weight of the vehicle better than steel or rubber tires on an equivalent vehicle , enabling a continuous tracked vehicle to traverse soft ground with less likelihood of becoming stuck due to sinking . The prominent treads of the metal plates are both hard - wearing and damage resistant , especially in comparison to rubber tires . The aggressive treads of the tracks provide good traction in soft surfaces but can damage paved surfaces . Special tracks that incorporate rubber pads can be installed for use on paved surfaces to prevent the damage that can be caused by all - metal tracks . Continuous tracks can be traced back as far as 1770 and today are commonly used on a variety of vehicles including bulldozers , excavator s , tank s , and tractors , but can be found on any vehicle used in an application that can benefit from the added traction , low ground pressure and durability inherent in continuous track propulsion systems . History . Perhaps the oldest implementation of something resembling continuous tracks is to be found in theories of prehistoric erection of large stone monuments , when megalith s may have been slid atop rounded wooden logs . The logs were grooved near their ends to be held in alignment and rotation by belts out past the edge of the megalith and lubricated by some means , probably organic . The logs are carried from the back of the procession to the front in an endless chain , like continuous track . The system is a precursor to development of the axle , which keeps a rotating cylinder fixed relative to its cargo . In modern times , continuous track propulsion systems can be traced back to a crude continuous track system designed in the 1770s by Richard Lovell Edgeworth . Polish mathematician and inventor Józef Maria Hoene - Wroński conceived of the idea in the 1830s . The British polymath Sir George Cayley patented a continuous track , which he called a " universal railway " . In 1837 , a Russia n inventor Dmitry Zagryazhsky designed a " carriage with mobile tracks " which he patented the same year , but due to a lack of funds he was unable to build a working prototype , and his patent was voided in 1839 . Although not a continuous track in the form encountered today , a Dreadnaught Wheel or " endless railway wheel " was patented by the British Engineer James Boydell in 1846 . In Boydell ' s design , a series of flat feet are attached to the periphery of the wheel , spreading the weight . A number of horse - drawn wagons , carts and gun carriages were successfully deployed in the Crimean War , waged between October 1853 and February 1856 , the Royal Arsenal at Woolwich manufacturing dreadnaught wheels . A letter of recommendation was signed by Sir William Codrington , the General commanding the troops at Sebastapol . Boydell patented improvements to his wheel in 1854 ( No . 431 ) - the year his dreadnaught wheel was first applied to a steam engine - and 1858 ( No . 356 ) , the latter an impracticable palliative measure involving the lifting one or other of the driving wheels to facilitate turning . A number of manufacturers including Richard Bach , Richard Garrett & Sons , Charles Burrell & Sons and Clayton & Shuttleworth applied the Boydell patent under licence . The British military were interested in Boydell ' s invention from an early date . One of the objectives was to transport Mallet ' s Mortar , a giant 36 " weapon which was under development but , by the end of the Crimean war , the mortar was not ready for service . A detailed report of the tests on steam traction , carried out by a select Committee of the Board of Ordnance , was published in June 1856 , by which date the Crimean War was over , consequently the mortar and its transportation became irrelevant . In those tests , a Garrett engine was put through its paces on Plumstead Common . The Garrett engine featured in the Lord Mayor ' s show in London , and in the following month that engine was shipped to Australia . A steam tractor employing dreadnaught wheels was built at Bach ' s Birmingham works , and was used between 1856 and 1858 for ploughing in Thetford ; and the first generation of Burrell / Boydell engines was built at the St . Nicholas works in 1856 , again , after the close of the Crimean war . Between late 1856 and 1862 Burrell manufactured not less than a score of engines fitted with dreadnaught wheels . And in April 1858 , " The Engineer " gave a brief description of a Clayton & Shuttleworth engine fitted with dreadnaught wheels , which was supplied not to the Western Allies , but to the Russian Government for heavy artillery haulage in the Crimea , in the post - war period . Steam tractors fitted with Dreadnaught wheels had a number of shortcomings and , notwithstanding the creations of the late 1850s , were never used extensively . In August 1858 , more than two years after the end of the Crimean War , John Fowler ( agricultural engineer ) filed British Patent No . 1948 on another form of " Endless Railway " . In his illustration of the invention , Fowler used a pair of wheels of equal diameter on each side of his vehicle , around which pair of toothed wheels ran a ' track ' of eight jointed segments , with a smaller jockey / drive wheel between each pair of wheels , to support the ' track ' . Comprising only eight sections , the ' track ' sections are essentially ' longitudinal ' , as in Boydell ' s initial design . Fowler ' s arrangement is a precursor to the multi - section caterpillar track in which a relatively large number of short ' transverse ' treads are used , as proposed by Sir George Caley in 1825 , rather than a small number of relatively long ' longitudinal ' treads . Further to Fowler ' s patent of 1858 , in 1877 , a Russian , Fyodor Blinov , created a tracked vehicle called " wagon moved on endless rails " ( caterpillars ) . It lacked self - propulsion and was pulled by horses . Blinov received a patent for his " wagon " in 1878 . From 1881 to 1888 he developed a steam - powered caterpillar - tractor . This self - propelled crawler was successfully tested and featured at a farmers ' exhibition in 1896 . Steam traction engines were used at the end of the 19th Century in the Boer Wars . But neither dreadnaught wheels nor continuous tracks were used , rather " roll - out " wooden plank roads were thrown under the wheels as required . In short , whilst the development of the continuous track engaged the attention of a number of inventors in the 18th and 19th centuries , the general use and exploitation of the continuous track belonged to the 20th Century . A little known American inventor , Henery T . Stith , developed a continuous track prototype which was , in multiple forms , patented in 1873 , 1880 , and 1900 . The last was for the application of the track to a prototype off - road bicycle built for his son . The 1900 prototype is retained by his surviving family . An effective continuous track was invented and implemented by Alvin Orlando Lombard for the Lombard Steam Log Hauler . He was granted a patent in 1901 and built the first steam - powered log hauler at the Waterville Iron Works in Waterville , Maine , the same year . In all , 83 Lombard steam log haulers are known to have been built up to 1917 , when production switched entirely to internal combustion engine powered machines , ending with a Fairbanks diesel powered unit in 1934 . Undoubtedly , Alvin Lombard was the first commercial manufacturer of the tractor crawler . At least one of Lombard ' s steam - powered machines apparently remains in working order . A gasoline - powered Lombard hauler is on display at the Maine State Museum in Augusta . In addition , there may have been up to twice as many Phoenix Centipeed versions of the steam log hauler built under license from Lombard , with vertical instead of horizontal cylinders . In 1903 , the founder of Holt Manufacturing , Benjamin Holt , paid Lombard $ 60 , 000 for the right to produce vehicles under his patent . There seems to have been an agreement made after Lombard moved to California , but when previous track patents were studied , discrepancies arose concerning how this matter was resolved . At about the same time a British agricultural company , Hornsby in Grantham , developed a continuous track which was patented in 1905 . The design differed from modern tracks in that it flexed in only one direction , with the effect that the links locked together to form a solid rail on which the road wheels ran . Hornsby ' s tracked vehicles were given trials as artillery tractor s by the British Army on several occasions between 1905 and 1910 , but not adopted . The patent was purchased by Holt . The Hornsby tractors featured a track - steer clutch arrangement , which is the basis of the modern crawler operation , and some say an observing British soldier quipped that it crawled like a caterpillar . The word was shrewdly trademarked and defended by Holt . American James B . Hill , working in Bowling Green , Wood County , Ohio , patented what he termed " apron traction " on September 24 , 1907 . Caterpillar Tractor Company began in 1925 from a merger of the Holt Manufacturing Company and the C . L . Best Tractor Company ; an early successful manufacturer of crawler tractors . Caterpillar brand continuous tracks have since revolutionized construction vehicles and land warfare . Track systems have been developed and improved during their use on fighting vehicles . During World War I Holt tractors were used by the British and Austro - Hungarian armies to tow heavy artillery and stimulated the development of tanks in several countries . The first tanks to go into action , the Mark I , built by Great Britain , were designed from scratch and were inspired by but not directly based on the Holt . The slightly later French and German tanks were built on modified Holt running gear . A concept vehicle called the Hyanide proposes a continuous track drive motorcycle . It involves a steerable continuous track to enable the vehicle to corner . The Canadian company BPG Werks has developed a dual tracked recreational vehicle called the DTV Shredder . This gasoline - powered vehicle consists of two caterpillar tracks steered by activating a dual CVT connected to the rider deck . As the rider leans the deck side to side , the speed of the tracks change allowing for differential steering . Patent history . A long line of patents disputes who the " originator " was of continuous tracks . There were a number of designs that attempted to achieve a track laying mechanism , although these designs do not generally resemble modern tracked vehicles . Blinov . In 1877 Russian inventor Fyodor Abramovich Blinov created tracked vehicle called " wagon moved on endless rails " ( caterpillars ) . It lacked self - propelling and was horse - drawn . Blinov got a patent for his " wagon " the next year . Later , in 1881 - 1888 he created a steam - powered caterpillar - tractor . This self - propelled crawler was successfully tested and showed at a farmers ' exhibition in 1896 . Dinsmoor . According to " Scientific American " , it was Charles Dinsmoor of Warren , Pennsylvania that invented a " vehicle " that was of endless tracks . The article gives a detailed description of the endless tracks and the illustration looks much like today ' s tracked vehicles . The invention has been patented as No . 351 , 749 on November 2 , 1886 . Lombard . Alvin O . Lombard of Waterville , Maine was issued a patent in 1901 for the Lombard Steam Log Hauler that resembles a regular railroad steam locomotive with sled steerage on front and crawlers in rear for hauling logs in the Northeastern United States and Canada . The haulers allowed pulp to be taken to rivers in the winter . Prior to then , horses could be used only until snow depths made hauling impossible . Lombard began commercial production which lasted until around 1917 when focus switched entirely to gasoline powered machines . A gasoline powered hauler is on display at the Maine State Museum in Augusta , Maine . Hornsby / Holt / Phoenix . After Lombard began operations , Hornsby in England manufactured at least two full length " track steer " machines , and their patent was later purchased by Holt in 1913 , allowing Holt to claim to be the " inventor " of the crawler tractor . Since the " tank " was a British concept it is more likely the Hornsby , which had been built and unsuccessfully pitched to their military , was the inspiration . In a patent dispute involving rival crawler builder Best , testimony was brought in from people including Lombard , that Holt had inspected a Lombard log hauler shipped out to a western state by people who would later build the Phoenix log hauler in Eau Claire , Wisconsin , under license from Lombard . The Phoenix Centipeed typically had a fancier wood cab , steering wheel tipped forward at a 45 degree angle and vertical instead of horizontal cylinders . Linn . In the meantime a gasoline powered motor home was built by Lombard for Holman Harry ( Flannery ) Linn of Old Town , Maine to pull the equipment wagon of his dog & pony show , resembling a trolley car only with wheels in front and Lombard crawlers in rear . Linn had experimented with gasoline and steam powered vehicles and six wheel drive before this , and at some point entered Lombard ' s employment as a demonstrator , mechanic and sales agent . This resulted in a question of proprietorship of patent rights after a single rear tracked gasoline powered road engine of tricycle arrangement was built to replace the larger motor home in 1909 on account of problems with the old picturesque wooden bridges . This dispute resulted in Linn departing Maine and relocating to Morris , New York , to build an improved , contour following flexible lag tread or crawler with independent suspension of halftrack type , gasoline and later diesel powered . Although several were delivered for military use between 1917 and 1946 , Linn never received any large military orders . Most of the production between 1917 and 1952 , approximately 2500 units , was sold directly to highway departments and contractors . Steel tracks and payload capacity allowed these machines to work in terrain that would typically cause the poorer quality rubber tires that existed before the mid - 1930s to spin uselessly , or shred completely . Linn was a pioneer in snow removal before the practice was embraced in rural areas , with a nine foot steel v - plow and sixteen foot adjustable leveling wings on either side . Once the highway system became paved , snowplowing could be done by four wheel drive trucks equipped by improving tire designs , and the Linn became an off highway vehicle , for logging , mining , dam construction , arctic exploration , etc . Sloan . Once steel cleats became unpopular on paved roads , in 1938 a limited experiment began to bridge the gap between truck and tractor , a " convertible vehicle " patented by Phillip Sloan , the C5 Catruk , suffered design flaws and limited production before it was finally abandoned . Engineering . Construction and operation . Modern tracks are built from modular chain links which together compose a closed chain . The links are jointed by a hinge , which allows the track to be flexible and wrap around a set of wheels to make an endless loop . The chain links are often broad , and made of manganese alloy steel for high strength , hardness , and abrasion resistance . Track construction and assembly is dictated by the application . Military vehicles use a track shoe that is integral to the structure of the chain in order to reduce track weight . Reduced weight allows the vehicle to move faster and decreases overall vehicle weight to ease transportation . Since track weight is completely unsprung , reducing it improves suspension performance at speeds where the track ' s momentum is significant . In contrast , agricultural and construction vehicles opt for a track with shoes that attach to the chain with bolts and do not form part of the chain ' s structure . This allows track shoes to break without compromising the ability of the vehicle to move and decrease productivity but increases the overall weight of the track and vehicle . Extra weight is an advantage when optimizing for traction and power over speed and mobility . The vehicle ' s weight is transferred to the bottom length of track by a number of road wheels , or sets of wheels called bogie s . Road wheels are typically mounted on some form of suspension to cushion the ride over rough ground . Suspension design in military vehicles is a major area of development ; the very early designs were often completely unsprung . Later - developed road wheel suspension offered only a few inches of travel using springs , whereas modern hydro - pneumatic systems allow several feet of travel and include shock absorber s . Torsion - bar suspension has become the most common type of military vehicle suspension . Construction vehicles have smaller road wheels that are designed primarily to prevent track derailment and they are normally contained in a single bogie that includes the Idler - wheel and sometimes the sprocket . Transfer of power to the track is accomplished by a drive wheel , or " drive sprocket " , driven by the motor and engaging with holes in the track links or with pegs on them to drive the track . In military vehicles , the drive wheel is typically mounted well above the contact area on the ground , allowing it to be fixed in position . In agricultural crawlers it is normally incorporated as part of the bogie . Placing suspension on the sprocket is possible , but is mechanically more complicated . A non - powered wheel , an " idler " , is placed at the opposite end of the track , primarily to tension the track , since loose track could be easily thrown ( slipped ) off the wheels . To prevent throwing , the inner surface of the track links usually have vertical guide horns engaging grooves , or gaps between the doubled road and idler / sprocket wheels . In military vehicles with a rear sprocket , the idler wheel is placed higher than the road wheels to allow it to climb over obstacles . Some track arrangements use return rollers to keep the top of the track running straight between the drive sprocket and idler . Others , called " slack track " , allow the track to droop and run along the tops of large road wheels . This was a feature of the Christie suspension , leading to occasional misidentification of other slack track - equipped vehicles . Overlapping road wheels . Many World War II German military vehicles , including all vehicles originally designed to be half - tracks and all later tank designs ( after the Panzer IV ) , had slack - track systems , usually driven by a front - located drive sprocket , the track returning along the tops of a design of overlapping and sometimes interleaved large diameter road wheels , as on the suspension systems of the Tiger I and Panther tanks , generically known by the term " Schachtellaufwerk " in German . There were suspensions with one ( sometimes double ) wheel per axle , alternately supporting the inner and outer side of the track , and interleaved suspensions with two or three road wheels per axle , distributing the load over the track . The choice of overlapping / interleaved road wheels allowed the use of slightly more torsion bar suspension members , allowing any German tracked military vehicle with such a setup to have a noticeably smoother ride over challenging terrain , leading to reduced wear and more accurate fire . As a tracked vehicle moves , the load of each wheel moves over the track , pushing down and forward that part of the earth , snow , etc . under it , similarly to a wheeled vehicle but to a lesser extent because the tread helps distribute the load . Apparently , on some surfaces , this consumes enough energy to slow the vehicle down significantly , so overlapped and interleaved wheels improve performance ( including fuel consumption ) by loading the track more evenly . It also must have extended the life of the tracks and possibly of the wheels . The wheels also better protect the vehicle from enemy fire , and mobility when some wheels are missing is improved . But this complicated approach has not been used since World War II ended . This may be related more to maintenance than to original cost . Mud and ice collect between the overlapping areas of the road wheels , freezing solid in cold weather conditions , often immobilizing vehicles equipped with such " Schachtellaufwerk " track suspension systems . The torsion bars and bearings may stay dry and clean , but the wheels and tread work in mud , sand , rocks , snow and so on . In addition , the outer wheels ( up to 9 of them , some double ) had to be removed to access the inner ones . In WW II , vehicles typically had to be maintained a few months before being destroyed or captured , but in peace time vehicles must train several crews , over a period of decades . Advantages . Tracked vehicles have better mobility than pneumatic tyres over rough terrain . They smooth out the bumps , glide over small obstacles and are capable of crossing trenches or breaks in the terrain . Riding in a fast tracked vehicle feels like riding in a boat over heavy swells . Tracks are tougher than tyres since they cannot be punctured or torn . Tracks are much less likely to get stuck in soft ground , mud , or snow since they distribute the weight of the vehicle over a larger contact area , decreasing its ground pressure . In addition , the larger contact area , coupled with the cleats , or grouser s , on the track shoes , allows vastly superior traction that results in a much better ability to push or pull large loads where wheeled vehicles would dig in . Bulldozers , which are most often tracked , use this attribute to rescue other vehicles , ( such as wheel loader s ) which have become stuck in , or sunk into , the ground . Tracks can also give higher maneuverability , as some tracked vehicle can turn in place without forward or backward movement by driving the tracks in opposite directions . In addition , should a track be broken , assuming the correct tools are available , it can be repaired without the need for special facilities ; something which is crucial in a combat situation . The seventy - ton M1 Abrams tank has an average ground pressure of just over . Since tire air pressure is approximately equal to average ground pressure , a typical car will have an average ground pressure of to . Disadvantages . The disadvantages of tracks are lower top speed , much greater mechanical complexity , shorter life and the damage that their all - steel versions cause to what passes beneath them . They are perceived / misconceived to severely damage hard terrain like asphalt pavement , but , actually , often have significantly lower ground pressures than equivalent or lighter wheeled vehicles . However , they often cause damage to less firm terrain such as lawns , gravel roads , and farm fields , as the sharp edges of the track easily rout the turf . Accordingly , vehicle laws and local ordinaces often require rubberised tracks or track pads . A compromise between all - steel and all - rubber tracks exists : attaching rubber pads to individual track links ensures that continuous track vehicles can travel more smoothly , quickly , and quietly on paved surfaces . While these pads slightly reduce a vehicle ' s cross - country traction , in theory they prevent damage to any pavement . Additionally , the loss of a single segment in a track immobilizes the entire vehicle , which can be a disadvantage in situations where high reliability is important . Tracks can also ride off their guide wheels , idlers or sprockets , which can cause them to jam in an overly tight position or to come completely off the guide system ( this is called a ' thrown ' track ) . Jammed tracks may become so tight that the track may need to be broken before a repair is possible , which requires either explosives or special tools . Multi - wheeled vehicles , for example , 8 X 8 military vehicles , may often continue driving even after the loss of one or more non - sequential wheels , depending on the base wheel pattern and drive train . Many manufacturers provide rubber tracks instead of steel , especially for agricultural applications . Rather than a track made of linked steel plates , a reinforced rubber belt with chevron treads is used . In comparison to steel tracks , rubber tracks are lighter , make less noise , create less maximal ground pressure and do not damage paved roads . The disadvantage is that they are not as solid as steel tracks . Previous belt - like systems , such as those used for half - track s in World War II , were not as strong , and during military actions were easily damaged . The first rubber track was invented and constructed by Adolphe Kégresse and patented in 1913 ; rubber tracks are often called Kégresse track s . Prolonged use places enormous strain on the drive transmission and the mechanics of the tracks , which must be overhauled or replaced regularly . It is common to see tracked vehicles such as bulldozers or tanks transported long distances by a wheeled carrier such as a tank transporter or train , though technological advances have made this practice less common among tracked military vehicles than it once was . Non - metal tread patterns . There are different varieties of non - metal core tracks that are designed for very different applications . Aggressive Tread Pattern . Aggressive tread NMC tracks have a more traditional lug style . They produce more pushing power and more tractive effort than their anti - vibration counterpart . Pros : - Greatly improves traction in loose ground or wet , muddy or otherwise challenging terrain . - Designed to be rugged enough to handle asphalt and other tough debris on job sites . Cons : - Increased tractive power means that these have a higher level of ground disturbance than anti - vibration NMC tracks . - The operator will experience greater vibration in the machine . Bottom Line : This track type is best suited for work sites that have a lot of loose debris or material on the ground . This rugged track pattern also is well suited to lend much needed tractive support in muddy or unstable terrain . Anti - Vibration Tread Pattern . The anti - vibration track is generally what is on your machine as the OEM component . This track has lower ground pressure than the Aggressive tread NMC tracks . Pros : - Allows machine to tread lighter , achieving less ground disturbance . - Very comfortable , vibration reduced ride for operator . Cons : - Less pushing power in the machine in comparison to the aggressive pattern NMC tracks . Bottom Line : This track type is best designed for applications such as landscaping work . You ’ ll have less rework and repair because of the reduced ground disturbance from this track type . Anti - vibration tracks are best suited for turf or other compact terrain that is mostly free of debris or loose materials . " Live " and " Dead " track . Tracks may be broadly categorized as " live " or " dead " track . " Dead " track is a simple design in which each track plate is connected to the rest with hinge - type pins . These dead tracks will lie flat if placed on the ground ; the drive sprocket pulls the track around the wheels with no assistance from the track itself . " Live " track is slightly more complex , with each link connected to the next by a bushing which causes the track to bend slightly inward . A length of live track left on the ground will curl upward slightly at each end . Although the drive sprocket must still pull the track around the wheels , the track itself tends to bend inward , slightly assisting the sprocket and somewhat conforming to the wheels . Current manufacturers . The pioneer manufacturers have been replaced mostly by large tractor companies such as Liebherr Group , John Deere , Yanmar , New Holland , Kubota , Case , Caterpillar Inc . , CLAAS . Also , there are some crawler tractor companies specialising in niche markets . Examples are Otter Mfg . Co . and Struck Corporation . Big Russian off - road territories forces many to develop and keep tracked transporters for the country . ZZGT , Vityaz and some other producers cover the needs of oil & gas , geophysics , forestry companies and governmental services .