Heavy Duty Trucking, November 2018
HDT NOVEMBER 2018 86 WWW TRUCKINGINFO COM ire makers will have their hands full over the next few years getting ready to meet Phase 2 of the EPAs greenhouse gas emissions fuel economy requirements GHG Phase 1 required the rolling resistance coefficient to be 77 but GHG Phase 2 demands the RRC be lowered to a 6 depending on the type of truck Phase 1 was 77 for all vehicles period explains Mahesh Kavaturu Goodyear commercial tires marketing manager Phase 2 has ratcheted down to 60 a 25 reduction Meeting those challenges will drive a lot of new technology Those rolling resistance numbers are actual measurements of a tires fuel efficiency but are not intended to be a tool fleets would use when specing tires The number represents only one of a tires many design criteria The numbers are derived from actual testing that EPA uses to rank tires as SmartWay verified or not The numbers are also used by truck makers in their Greenhouse Gas Emissions Model GEM certification to quantify the efficiency of the tires they plan to use on a truck In that context the drop from 77 to 60 is a very real 25 reduction in rolling resistance and something the tire makers will have to contend with Each vehicle classification comes with its own rolling resistance target Sleeper cabs are 60 for example while the target for vocational trucks is 75 Faced with an overnight change tire makers Tires for the future EPAs GHG Phase 2 rules are still a couple of years off but tire makers are already designing and testing new ultra low rolling resistance tires could probably build a tire with much lower rolling resistance today but such a tire would come with unsatisfactory miles to removal tearing and chipping risks and even traction losses No fleet or driver would tolerate that so the process of developing future tires that not only meet the GHG Phase 2 requirements but also satisfy fleet expectations are well underway We have only a couple of years before the first tier of reductions hits in 2021 The traditional pathways to lower rolling resistance have involved tinkering with the tread and sidewall rubber compounds and reducing the depth of the tread These approaches achieve the goals but sometimes there are undesirable side effects When some tire makers formulate tread By Jim Park Equipment Editor jpark@ truckinginfo com TIRES WHEELS T PHOTOS JIM PARK Tires built for trucks after 2021 when GHG Phase 2 kicks in will have to be more efficient with less rolling resistance but they will still have to meet fleets expectations for tread wear and tire life
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