C 15 descending hills question

Discussion in 'Experienced Truckers' Advice' started by Coloradoman, Oct 22, 2020.

  1. Coloradoman

    Coloradoman Light Load Member

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    So I run a lot if mountain passes, just got into this 06 w900 with the single turbo. The problem that I'm having is going down steep Colorado grades loaded, seems like any gear I choose the RPS are a pain to keep under 2k without using the service break more than I want to. So looking for advice from some old school guys, seems like the twin turbo held me back a lot better, every one I talk to just says a low gear but I still end up breaking to keep RPS under that 2k Mark.
     
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  3. D.Tibbitt

    D.Tibbitt Road Train Member

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    Try and go down in the same gear u go up in or 1 gear lower...2 lower u should be able to get down with no jake and light pressure on the brake pedal.. But ur gonna be going painfully slow like 10 or 15mph ... dont know anything about the c15, but i run out west like u .. usually 1 gear lower than i went up is how i do it
     
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  4. Coloradoman

    Coloradoman Light Load Member

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    That's what I do but I still need to use the break a lot, at least it seems like a lot, just to keep RPMs lower and with winter #### near here I would rather not use the service breaks much lol.
     
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  5. Long FLD

    Long FLD Road Train Member

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    All the single turbo Cats I drove would hold 105k on a 6% grade between 20-25 mph.
     
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  6. Coloradoman

    Coloradoman Light Load Member

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    It's not the speed, its the RPMs. Seems like no matter what I do they are pushing 2k. I tried a couple different things heading west out of denver today with a load of stacked trailers and it was still the same, speed was fine (slower) but RPMs would just be to high.
     
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  7. uncleal13

    uncleal13 Road Train Member

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    You’re just going too fast. You slow down and drop gears until you find one that holds it.
    The craziest hill I went down, 140,000 lbs , 11% grade for 4.5 miles with a stop light and turn at the bottom. I went down in third gear on a 18 speed at 7 mph. Yes that works out to 35 minutes to get down that hill. Only had to snub the brakes twice.
     
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  8. Brandt

    Brandt Road Train Member

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    In snow or ice you want to use the service brakes and not the engine brake. The differentials apply the engine brake to the tires with the least amount of traction. That why you see truck in parking lots one drive tire spins and the other 3 don't move. If on dry roads then the differentials will apply even power to all drive tires. You turn off the engine brake in snow or ice and use all 10 brakes. You can get away using the engine brake in snow and ice. Lots of drivers do, just remember it applies the engine brake to tires with least amount of traction.

    I was trained you want light steady pressure on the brakes 10 PSI or less. So you go down any hill with any weight that 10 PSI or less will hold your speed. Because the brake drums can dissipate that much heat without overheating. So in snow or icy you don't need the engine brake just the regular brake. You will be going very slow like someone already said 15 MPH or something. Then I use the engine brake to go faster downhill when the roads are more dry. I run the engine brake plus 10 PSI or less pressure on the brakes. I'm getting the most brake from regular brakes plus the engine brake all at the same time. I'm going as fast as safely possible. Your truck needs to have Applied Brake Pressure gauge for this to work.

    In snow or ice I turn off the engine brake and use the regular brakes to get me down a hill. We were trained you want low RPMs like 1200 going down hill because if trailer starts to slide and come around the tractor. First thing you do it take foot off brakes to get all the tires rolling. Then if trailer keeps jackknifing. You have one option left to save it and yourself. You step on the pedal and pull the trailer down hill and back behind tractor. Then you use the brakes to slow down again. This something I don't hear anyone ever say.
     
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  9. Coloradoman

    Coloradoman Light Load Member

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    The speed limit was 45 down vail and I was doing about 35, went down two gears lower than I went up. This one is a 13 speed. Maybe just go three gears lower?
     
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  10. Coloradoman

    Coloradoman Light Load Member

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    I'm not all that new to driving (9 years) I'm just looking for pointers for a truck that makes noise but has little hold back lol.
     
  11. Long FLD

    Long FLD Road Train Member

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    You just have to keep slowing down and dropping gears until the engine brake holds it.

    And you can use your engine brake going downhill in snow, you may have to drop another gear and run in stage two instead of three, but you can run it and not ride your brakes all the way down.
     
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