1976 MACK R686 ST

1976 MACK R686 ST. The Mack R series is a line of Class 8 heavy-duty trucks introduced in the early 1960s by Mack Trucks. It replaced the very successful Mack B series models. R Model production ran for 40 years until the RD model was discontinued in 2004 and the RB and Mack D series DM models were discontinued in 2005. The first R models introduced were powered by Mack Thermodyne diesel and gasoline engines. In 1973 the R cab was given a makeover to include a deeper rear wall for more room and a new dashboard design. R series Mack started to produce the R and RW in 1966 for highway use, the RD and all wheel drive RM were for construction and municipal use. The lightweight RL model followed in 1967, the RW Superliner with a large, rectangular hood and grill in 1977, and the setback front axle RB in the 1990s. In the 1990s the R and RW were discontinued and the RB was introduced, mostly for severe-duty applications. The hood was modified slightly for the model RB. 2004 was the last year for the RD, and 2006 for the RB. Model designations • R - Standard model • RB - Set back front axle (except in New Zealand - see NZ Mack RB) • RD - Heavy Duty R • RM - 4x4 Municipal/maintenance chassis • RMM - 6x6 Municipal/maintenance chassis • RS - Western R series, S stands for steel frame • RL - Western R series, L stands for Aluminum frame • RW - Western series, replaced by the Mack Super-Liner • U - Short hood offset cab • DM - Heavy duty U • DMM - All wheel drive DM • Chassis numbers (GVW Rating): o 4xx - o 6xx - o 7xx - o 8xx - Note: the xx is the place holder for the engine code. • Suffix letters: o T - Tractor o S - Six wheel chassis o L - Light weight components o X - Extreme duty Gross Vehicle Mass: 31,752kg Tare Weight: 8,300kg Axle Type: 3-Axle Tandem Drive CC rating: 11,040cc 672 ci (11.0L) I6 NZ First Registration: 13-Feb-1976