COST 334

Chapter 4for a given rim diameter, the wide base single tyres generally have higher recommendedtyre inflation pressure for the same axle loads than dual tyres.Recent roadside surveys showed that the tyre inflation pressures of dual tyres weregenerally lower than those of wide base single tyres. However, the axle loads weredifferent. Over the last thirty years tyre pressures have been increasing, but higher tyreinflation pressures have been used in wide singles when compared to dual tyres. This hasoccurred due to tyre design and existing standards. At present wide single tyres haveslightly higher pressures. However, from the design point of view there is no reason whywide single or dual tyres cannot have the same inflation pressure for the same load.Inflation pressure (bar).1098765432100 5000 10000 15000Axle load (kg).385/65R22.5425/65R22.510R22.5445/65R22.511R22.5315/80R22.5Figure 4.19- Recommended tyre inflation pressure vs axle load, towed axles, R22.5tyre sizesversion 29 November 200155