Page 2 of 2 FirstFirst 12
Results 11 to 17 of 17

Thread: Driving In Mountains

  1. #11
    Join Date
    Nov 2006
    Location
    Sugar Land, TX
    Posts
    1,307

    Default A little more driving lesson please

    Ok, so how about a few more lessons in driving down big hills, with ONLY the JAKE brake and transmission to control your speed?

    I don't have a transmission retarder to help me.

    At the top of the hill going say 35mph, do you downshift into 2 or 3rd and maximize the Jake brake to cruise slowly down the big hill? And will that be enough to maintain a slow speed without over reving your rpm's?

    Gary S.

  2. #12
    Join Date
    Mar 2006
    Location
    Santa Barbara
    Posts
    3,177

    Default

    Hi Gary. I would find the seed at which you are comfortable depending upon the grade. Usually 4th or 5th works but I would still use the jake.
    Gary & Lise Deinhard, 2003 Elegant Lady Liberty, Dbl slide

  3. #13
    Join Date
    May 2006
    Location
    LaBelle
    Posts
    473

    Default

    Gary,
    There are three factors involved in controlling downhill speed. You mentioned two but don't overlook your brakes; they are a necessary part of the safe speed equation. Depending on the hill the Jake brake and transmission may not control the downhill speed. As speed is increasing, use the stab method of braking. Apply the brakes to reduce the speed to at least 5 mph under the speed limit then release the brakes. Allow the Jake and transmission to hold you back until you gradually reach the speed limit again. Then apply the brakes to slow you down to 5 mph under the speed limit. Keep repeating this process until reaching the bottom. Again, you go down the hill in the same gear that you went up it in. Depending on the downside, you may have to go to the next lower gear. It is a trial and error method to control the speed. Don't ride the brakes or they will overheat and they won't be there when you need them. Plus the smell of overheated brakes stinks.
    Denny

    Denny & Ruth Ann
    2008 H3-45 Millennium; 2018 Ford F-150

  4. #14
    Join Date
    Nov 2006
    Location
    Montrose
    Posts
    188

    Default

    With a jake and a big hill select a gear that will hold you back with the engine RPM close to 2000 rpm. As Jon said stab the brakes to control speed. If the jake is not holding you back get on the brakes hard to slow down then select a lower gear. As I drive the big hills I use the jake and save the brakes for the guy that may pull out in front of me. In the mountains saving the brakes is key. Here in western Colorado one sledom drives on level roads so I rarely turn off the jake until there is a lot of flat ground.

  5. #15
    Join Date
    Jan 2006
    Location
    anytown
    Posts
    8,908

    Default

    There are a couple of things folks need to know about the downside of hills and Jake Brakes.

    First, a Jake is not going to have the ability to hold back the bus that a retarder has. A typical Jake only develops about 1/2 the horsepower of the engine. So when working a Jake you need to slow down at the crest and be in the lowest gear suitable for the speed.

    A Jake works best at high RPM and hardly at all at lower RPM so downshifting is important.

    If the Jake will not hold the speed you want then you must apply the brakes. Typically apply the brakes at your target speed and slow the coach down about 10 MPH before releasing them. DO NOT PUMP THE BRAKES BUT APPLY CONSTANT PRESSURE TO SLOW DOWN. DO NOT "RIDE" THE BRAKES. Our brakes require air to work and pumping the brakes depletes the air supply. Riding the brakes heats them as Denny points out and hot brakes are less effective. Apply the brakes firmly to get slow and then let the Jake take over.

    If you have selected the right speed and proper gear it is possible the Jake at the highest setting will actually slow the coach without the use of brakes. When that happens you can toggle between the Jake settings (high to low and back again) to keep your speed in the desired range.

    We have had both the Jake Brake and a retarder. Both require you to participate, selecting the proper gear and speeds. Each has its benefits and shortcomings. What is critical to remember regardless of which system you have is that bringing 50,000 pounds safely down a hill requires the management of energy and that starts at the top of the hill with the correct gear and speed. If you wish to maintain normal driving speeds down a hill understand that your already long stopping distances are going to increase significantly and you are placing your safety solely in the ability of your brakes to do their job. Don't do that. Be safe. Use the Jakes and retarders to help you.

  6. #16
    Join Date
    Nov 2006
    Location
    Montrose
    Posts
    188

    Default

    Today I drove east down Monarch Pass (US50) in Colorado. The speed I wanted was the speed that allowed the Jake to hold me back without using the brakes. For the top 5 miles or so that was 3rd gear at 2000 rpm. I never touched the brakes for the five miles but did lightly touch the throttle when jake began to decrease my speed. Just a light touch of the throttle turns th jake off but also allows the jake to come back on the instant the throttle is released. Works great for me. As the grade became less steep I unshifted to 4th gear.

  7. #17
    Join Date
    Nov 2006
    Location
    Huntsville
    Posts
    3,123

    Default

    There's some good info in this article that closely relates and supports the advice in the Post/Article on using the Transmission Mode Button. http://forum.prevostownersgroup.com/...N-TRANSMISSION

    As pointed out in both posts, the main thing is learning how/when to punch that mode button or the up and down arrows. Fortunately, with the Allison transmission, it is smart enough to do most of this by itself, but there are advantages to knowing how to do it yourself.
    Dale & Paulette

    "God Loves you and has a plan for your life!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •