Large, powerful cars and SUVs with electric or hybrid drives are substantially heavier than conventional ICE-powered vehicles and thus need tyres that can handle greater loads. The solution is to fit tyres with a higher load index. The gold standard here is HL, or High Load. Continental has introduced the first passenger tyre with the new HL load index code, HL 245/40 R19 101Y XL. It is currently evaluating demand for further HL sizes.
The European Tyre and Rim Technical Organisation (E.T.R.T.O.), an industry association whose membership list includes all major tyre manufacturers, set HL load designation as an industry standard. What sets HL tyres apart from XL and standard tyres is their higher load capacity at the same inflation pressure. Using the example of 245/40 R19 – a tyre size worn by many mid-sized vehicles – Continental explains that a standard SL load tyre in this dimension can handle a maximum load of 670 kg (load index 94). An XL load index tyre can cope with a load capacity of up to 750kg (load index 98) and a HL load index tyre a load capacity of up to 825kg (load index 101). This means that a HL tyre’s load capacity is almost a quarter greater than that of a standard tyre.
Reinforced construction & optimised compound
Continental needed to make a number of changes to the tyre’s structure and rubber compound in order to increase load capacity while continuing to meet other customer requirements. “We were dealing here with trade-offs that needed resolving at a very high level,” comments Dr Stefan Habicht, who was in charge of Continental’s HL tyre development project. “In terms of construction, we reinforced the bead and enhanced the contour of the tyre to reduce tyre/road noise. At the same time we also optimised the pattern compound. As a result, we were able to achieve low rolling resistance, ensure precision handling and keep mileage at its customary high level.”
While Continental hasn’t announced specific information about product availability at this point, it says it will offer tyres with HL load indices both as original equipment and replacement fitments. Looking ahead, Continental anticipates rising demand for HL tyres from vehicle manufacturers.