track support rollers also as the bulldozer falls or pitches forwardly after climbing a wave there will be impact loading of some of the rollers the more violent the pitch motion the greater the loading on some of the rollers will be this is made evident by inspecting the graphs depicted in fig5 and 6 which cover the same time frame covered by the graph depicted in fig4 and show the ground support forces experienced at any given time by the second third and fourth track support rollers as considered from front the rear the graph in fig5 relates to a bulldozer having conventionally arranged track support rollers while the graph in fig6 relates to a bulldozer having track support rollers arranged in accordance with the present invention as illustrated in either fig2 or fig3 referring to fig5 the lines a b and c respectively represent the ground forces experienced by the second third and fourth rollers and it can be seen that the forces experienced by these rollers generally cycle through ever increasing peaks once the initial five seconds of operation have passed the largest peak forces experienced by the second third and fourth rollers occur between 18 5 and 19 5 seconds and are 1 13 1 2 and 0 98 u00d7 10 5 newtons respectively as can be seen in fig6 where the lines a 39 b 39.