Advice for driving down steep grades....

First. Don't race to the top of the grade. I see this all the time. BIG warning signs (like Cabbage, for example) and I'll see loaded trucks go 70mph until the downgrade and "throw themselves over the hill", meaning they could have started coasting and slowing in advance and let the jakes take them down the grade.

Find a gear that allows the jake to keep you at a steady and safe speed. Read the posted signs for grades and they sometimes have a speed limit for big rigs, which factor in your loaded weight.

Getting the feel for taking down grades didn't take me very long. The biggest challenge is to trust the signs and don't let yourself coast too fast. Use the jakes and avoid using your service brakes so you don't over heat them.

 

Excellent question. Keep an eye on your tach when you can. The idea is to be slowed before a serious downgrade to the advised speed.

I usually downshift at about 1100 rpm so I can get into the next lower gear at no higher than 1400, maybe less depending on how fast you are slowing down.

I don't know of a great way to explain this via text forums...

If the need to downshift should arise on a downgrade, use your service brakes and slow in your current gear to 1000-1200 RPM. This will allow plenty of headroom on your RPMs to get down without going above the green.

 

Also.... treat the shifter and throttle like a lady. Be gentle. You don't have to hit the throttle hard to get some RPM up. Remember, the newer trucks are drive-by-wire, so it's an electronic throttle. The point I'm trying to make is, don't mash on the pedal. Take some time in a controlled environment (parked or in a Swift yard) to get to feel how your throttle responds while keeping an eye on your tachometer.

Soon enough, you will either not really need the tach, or you will notice you have gained a more natural feel for how to respond and drive your truck. This includes cornering, backing, shifting, docking and coupling/uncoupling your trailer.

Take your time. No rush. Remember one important thing. Commercial vehicles don't drive or respond like a four wheeler or race car, so you have to treat the rig as such... a BIG rig.

This stuff was all VERY intimidating to me at first. I learned how to pace myself and not over-rev and the rest fell into place quickly.

 

practice. just repitition. You'll come to know how your truck runs in due time. Just pay attention to what you do and learn from the mistakes that WILL happen.

 

I don't know how you guys do it, but I relate my gears to the speed. If I am doing 45, I know I need to be at least in 9th gear (I add 4+5 from my 45 mph speed,). This rule of thumb works for gear #6 (15 mph) thru gear #10 (55 mph). I usually drop my gears down at 1100 rpms when it reaches or matches my rough ground speed rule. If I go down a steep grade with a posted safe speed with.. let's say 55 mph, I drop down to 9th before I make my descent. My truck will still build up speed up to 55, but it won't go that much faster. I firmly apply my brakes until I drop down to 50 mph, and then let off my brakes and let my truck roll up to 55 mph again before I start to apply my brakes again.

 

I learned grades rolling 80,000 with dogfood on the wagon in WV on 64. (7-9% grade over 20 mile stretch) with NO JAKE. The first time I did it I had to pull off the left shoulder and let brakes cool. really, it's pretty simple. you can work the brake in any gear. you let it go up to 1600-1700 rpms or so, then you brake it down to 1000-1100 rpms. When you brake you want to brake solid and even. you DO NOT want to ride the brakes easy, you push good and solid and get the rpms down, then let off. the tricky part is choosing the gear that will get you to the bottom. the lower gear you choose, the less heat your brakes develop each time they're applied. With my heavy truck and no jake I often had to work it under 20mph ! err on the side of caution, a big grade you can start in 4th or 5th with a 10 speed. remember, you can always shift up, it's the shifting down that is dangerous.

 

PLEASE do your self and everyone else a favor and do not down shift if you are already going down the hill,DO NOT EVER EVER EVER take it our of gear when you are going down a hill

 

you aalways have to lose speed before downshifting. you should be down around 1300 or so before you drop a gear. When you slow down your speed you will also lose the rpms. Biggest deal relax take your time and get ready ahead of time.