Effect of ballasting on performance characteristics of bias and radial ply tyres with zero sinkage

A study on performance characteristics of tyres such as deflection and contact area is useful to determine the optimum condition for maximizing tyre efficiency. Differences in design and dimensions of pneumatic tyre affect the output power of the tyre. Present study was conducted to evaluate the vertical deflection and contact area of 13.6-28 bias-ply and radial tyres at different ballasted conditions with five normal loads which are (i) Base weight (B0 = 1050 kg), (ii) Base weight + 50% water (B50), (iii) Base weight + iron weight equivalent to 50% water (BFe50), (iv) Base weight + 75% water (B75) and (v) Base weight + iron weight equivalent to 75% water (BFe75) at various inflation pressures ranging from 68.9 to 206.8 kPa on hard surface in controlled soil bin. It was observed that both the selected tyres showed better performance under ballast load of BFe75 over the other selected loads. At all the selected loads, the radial tyre showed 13% higher contact area and 6.5% greater deflection than the bias-ply. The obtained results at various test conditions were compared with the existing predicting models for deflection and contact area using curve fitting technique in order to select the best suitable model.