Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/894232
lison automatics with no problems." When citing the advantages of au- tomated transmissions, our sources first mentioned the benefit to less- experienced drivers who would have trouble with a manual trans- mission. While that's true, improved fuel efficiency and reduced drive- line shock are just as important. Older products make a comeback Remember super single tires? They enjoyed popularity briefly before issues cropped up to kill the de- sign. They're back, now known as wide-base tires. Some of the earlier problems have been addressed. Self-sealing models reduce the risk of having the one tire on an axle go flat, leaving no limp-home mode as duals offer. More tread patterns and longer tread life are available. But the fact remains that one wide-base tire is heavier and more difficult to handle than a single tire from a dual setup, and there's still uncertainty about bearing wear on axles retrofitted with wide-base tires, even when mounted on offset wheels. Wide-base tires are gaining acceptance at all wheel positions on line-haul tractor trailers, but construc- tion is slower to return to the design, and some markets, such as forestry and demolition, will likely never be appropriate for wide-base singles. Likewise, disc brakes, which made a brief foray into commercial trucks in the late 1970s and early 1980s, are also making a comeback. Early designs had lots of problems. Some had high hysteresis, which is the lag between a component's movement and changes in force that create the movement. When brakes were re- leased, the pads were slow to retract; they would apply well but release poorly. Also, pads were attached to the caliper, subjecting the caliper to clamp loads and brake torque. Single- piston calipers did not yield balanced pad wear. Current designs have none of the issues associated with the early mod- els. Barry says today's air disc brakes (ADBs) stop 40 percent faster, have 40 percent longer service life and have no issues with fade. And swap- ping brake pads is much faster than changing brake shoes. "It takes less time to change pads than it does to pull the wheel," says Barry. The surging popularity of discs is due in part to the National High- way Traffic Safety Administration's mandate of a 30 percent reduction in stopping distance for large trucks and the ability of ADBs to meet that mandate. Drum brakes haven't gone away and continue to benefit from advances in design and material, but Barry says once key players adopt ADBs, others will follow. He expects ADBs to be the dominant brake type on vocational trucks within five years. EquipmentWorld.com | November 2017 39 2905 Shawnee Industrial Way, Suwanee, GA 30024 T. 866-563-5890 E. ussales@geith.com Geith and the Geith logo are trademarks of Geith International Limited. TOUGH by the BUCKETFUL. Geith attachments are made stronger, designed to work harder, and engineered to fit perfectly on your excavator. There are buckets, and then there are Geith buckets. See what we're made of at Geith.com Untitled-9 1 10/4/17 8:26 AM