azcardnlz Posted July 19, 2015 Share Posted July 19, 2015 I'm looking at a '12 Mack Pinnacle with an MP8, 10 speed, and 3.36 gears. It's a 445 horsepower engine but the salesman doesn't know more than that. I'd guess a 445C, but until I get my hands and eyes on it, I don't know for sure. It seems that during those times I drive 55mph, the engine will be turning at 1125 RPM in 10th, and 1525 RPM in 9th. Is 1125 too low to run for extended periods of time? Is 1525 too high for decent fuel mileage? I know the Mack is good at handling low RPMs, but for an extended amount of time? I'm trying to get some clarification before I take time off and take a trip to go see it. Thanks in advance. Quote Link to comment https://www.bigmacktrucks.com/topic/40988-considering-my-first-mack/ Share on other sites More sharing options...
wiserfrombud Posted July 22, 2015 Share Posted July 22, 2015 Just curious about your operation? If you are very light and run mainly flat land, I think 10th would work alright. My truck runs nice @ 1150 on the flats. Which would be 56 or 57 mph I'm guessing? Are you sure it's a 400 rpm jump to 9th? 1525 is too high for fuel economy imo. Quote Link to comment https://www.bigmacktrucks.com/topic/40988-considering-my-first-mack/#findComment-297499 Share on other sites More sharing options...
azcardnlz Posted July 26, 2015 Author Share Posted July 26, 2015 400 RPM has been my experience on 10 speeds, and 200 RPM with 13 speeds. 10th to 9th would be the same as 13th to 11th. I run spot market freight in 47 states. The 2012 truck will open up California to me. Weights are always different, but nothing that puts me over 80K. Quote Link to comment https://www.bigmacktrucks.com/topic/40988-considering-my-first-mack/#findComment-297961 Share on other sites More sharing options...
j hancock Posted July 26, 2015 Share Posted July 26, 2015 Sympathy for anyone operating in California. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/40988-considering-my-first-mack/#findComment-297972 Share on other sites More sharing options...
azcardnlz Posted August 16, 2015 Author Share Posted August 16, 2015 Not my favorite place, but it opens up some options. Quote Link to comment https://www.bigmacktrucks.com/topic/40988-considering-my-first-mack/#findComment-300305 Share on other sites More sharing options...
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