Cranfield University

Laboratory Studies Into Undercarriage Systems
3.2 Evaluation of Implement Tyres and Whole Combine Harvesters
Following Ansorge (2005, a) it was important to investigate the effect of the additional
passage of the rear tyre on the soil when considering whole machines. Particularly interest-
ing was the question whether the advantage gained by using tracks at a total load of 12 t in
comparison to tyres at a total load of 10.5 t (the smaller load accounts for the lighter under-
carriage system) could be maintained after the passage of a rear tyre at a load of 4.5 t. To
conduct this study first rear tyres are evaluated on their own. Details of the rear tyre speci-
fications including the load of 4.5 t and the corresponding inflation pressure are shown in
Table 4. The abbreviation used for the single rear tyres is listed, too.
Table 4: Rear tyre specifications
Tyre Load (t) Inflation Pressure (bar) Abbreviation
500/70 R24 4.5 2.3 500-70/4.5/2.3
500/85 R24 4.5 1.4 500-85/4.5/1.4
600/55 – 26.5 4.5 1.4 600/4.5/1.4
710/45 – 26.5 4.5 1.0 700/4.5/1.0
Afterwards whole common combine harvester undercarriage system comparisons will be
conducted. Additional machine configurations will be investigated as detailed in Figure 1.
Table 5 gives a listing of all the simulated machine configurations with tyre, track, load,
and inflation pressure combinations and assigns an abbreviation to each.
The 680-700 was assumed to act as a dual tyre configuration on the front axle. Due to the
width restriction of the soil bin, no true dual configuration with two 680 tyres side by side
could be realized. Hence, the load was halved for one tyre and for simplicity no interaction
between the two tyres was assumed. This assumption is justified due to the punching type
of soil failure already observed by Ansorge (2005, a) and explained in Section 7.5.
Ph.D. Thesis Dirk Ansorge (2007)
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