Anyone had to use a runaway truck ramp?

I think the difference in opinion is not so much older drivers, but more' that some drivers will see 50 grades a day, while others see one or two light interstate grades a week or even less.

 

Anybody who regularly runs I-80 across Wyoming in winter knows that conditions can get really slick and chains are rarely used on the wide open flat plains. A few years ago I was there on a -15 degree morning with the sun out. The road was a solid sheet of ice and I was only going around 45 at the most. I didn't realize that my jakes were on minimal setting, and I let off the throttle going down a grade, and the drives immediately began to kick sideways and started to jackknife. All I had to do was accelerate a little to recover, but I can see how it can get real very fast.

 

If jakes were locking up the wheels on minimal setting, I am surprised that you could accelerate at all without spinning. Wheels will spin under power, much before the jakes will lock them generally.

 

Several lifetimes worth of hard earned Jacobs Knowledge here.

Im seriously impressed.

 

One of the things that people don't realize is that using a Jake is similar to using compression in a gas engine. Diesels don't have a throttle body, so taking your foot out of it only shuts down fuel. In a gas engine, taking your foot out of it throttles, chokes, the engine, and causes braking power.

 

I am a little surprised here that some drivers do not understand why jakes are more dangerous than service brakes in slippery conditions.

Jakes only exert force on the road on the same wheels that the engine is using for acceleration. During most normal operations, that will be your right front drives. This means your jakes will exert a rotational force on the tractor when they engage. On good pavement, that isn't an issue. On ice/water/oil it can cause havoc.

Two other issues that can make jakes dangerous.

First, by concentrating all braking force on one side of one axle, it makes it likely that your right front drives will break free of the road. *ABS does NOT work for jakes!!* Jakes have a direct driveline connection to the motor!

Second, if your jakes break your active powered drives free of the road on a curve, all of the other tires of your truck will instantly have to do more work to keep your truck on the road. If the road conditions are bad, this could lead to a rapid cascade of tires losing friction one after the other, followed by your truck's center of mass going in a straight line, off the road.

If you engage the differential lock, that will reduce the chances of the truck breaking jakes free of the road. Engaging both differentials will help more in bad conditions. But your Jake's will never act on your steers or trailer brakes, which makes them intrinsically more dangerous in slippery conditions.

 

That's why I avoid talking about using Jacobs in storm. Some newbie might give it a try and learn the hard way when it goes straight off a mountain.

With that said, it's a wonder that axles do not snap like a toothpick under certain situations.

 

back in the day before automatic slack adjusters is what you were looking for making sure the brakes were tight enough to hold you down the hill...it's where many people died back in the day on West Coast steep grades when they lost their brakes on a long drop know Jake's know nothing that was the purpose of them back in the day...so much with automatic slack adjusters the last 20 years you really don't does not much to check.
after 29 years out here. I basically drop down the hill I give it the respect that I want returned and go downhill as many times as you want as slow as you want you're only going down one time too fast.. how I was trained it 1990.
and I don't care I've got an automatic Volvo now and I basically just slow down so it gears down and there I just let it fall itself down start down a grade about 25 miles an hour just like I did back in the day with a 300 Cummins with no Jake I let the Jake do the work and it holds that automatic transmission back perfectly fine..

As far as to your answer; if I ever had to use one? no but I came close 3 times its right in my memory too.
one time 1991 with JB Hunt.. loaded heavy coming out of the south gate terminal little 300 un jaked slip seated company truck
headed up just to Sacramento at the grapevine started out just one gear too fast started pumping the heck out of the brakes halfway down smoke the hell out of them.. hit that ta Wheeler ridge but halfway down I thought I had to grab that escaped ramp but it was too late I already passed the last one and that little cornbinder was picking up speed. needless to say I made it. looked like little fire underneath. those trucks back in the day and I was young and naive driving less than 6 months at the time but I remember it real well.
2. 1996 working for OTR Express.
out of Olathe Kansas. had one of the gray international 9300 was a 94 at the time.. coming down homestake pass in Montana down into Butte headed out to seatac area I just loaded 2 days earlier. I came out of the house in Chicago area loaded in Kenosha Wisconsin.. Had Jake on was one of the wires on the Jake decide to give out halfway down to and it started cutting out I wasn't doing the suggested truck speed
about seven to eight mile an hour or more. heavily loaded. the J Jake on that 3406e kept cutting in and out cutting in and out shutting off while still in the on position had there been about one and a half more miles to downgrade I would have had to take in the escape ramp no doubt about it.. but the last little leg of homestake got towards the bottom there and picked up a lot of speed headed interviewed but it was okay it flattens out quick and was able to stop down at the old Flying J at Rocker.
3. about 3 years ago when I got my first automatic Volvo not familiar with steep grades and running it. i-64 sandstone Mountain West Virginia started down way too fast..stop the automatic transmission with shift itself down it doesn't do that. set is starting down and letting the Jake do the work in about 25 or 30 I started out about 40 had no idea how to get the thing to downshift I was more worried about manually shifting it down and over revving the engine..about halfway downknew I was going way too fast using way too much brake power they started smoking really good saw escape ramp but kept smoking the heck out of the brakes that last mile to end. I wasn't a full-blown run away to where I was going 80 or 90 mile an hour like some of these people that end up hitting an escape ramp for truck supposed to be 35 or 40 and your face hairpin curve at 35 miles an hour.. so I saw the ramp there but I didn't take it Dan kind of went way way too fast 2 words to buy them but if you know 64 on sandstone it does flatten out and it goes back up again so I got to the bottom and was moving but I just left the thing cool itself off over the next four or five miles.
but luckily in 29 years I've never had to take an escape ramp but I've learned through the years you see me in my Volvo out there on a 6% grade or more for more than three or four miles I'm happily chugging along with my four-ways on at about about 25 to 30 miles an hour let everybody fly around as fast as they want to go I can care less you want to go 50 down inTruck restricted 35 more power to you I got no respect for you anyway.. is out never forget when the Jake quit its electronic it could happen anytime even on a brand new truck all it takes is one wire to come loose off of a harness..

 

I use them but only on the usually between 1 and 2 I don't use it in 3 but I start down even slower and inclement weather so that way when I do have to use it I can hold it in one or two and I don't need the crank it up to 3

 

Actually, what I think is the biggest issue here, is that there's a failure to understand that not all inclement road conditions are equal. Snow pack can have a quite manageable traction curve, whereas as the peak on the curve for ice has a much worse drop off the back side. That's not to say the jakes aren't more dangerous, although that's rather a extreme way of putting it. Jakes are just another tool, with a proper time for usage. Barefoot, on glare ice near freezing? Yeah, that's asking for it. On decent traction snowpack, it's not an issue.

A differential distributes power evenly until a wheel slips. This "one corner" misconception is probably one of the most widespread in the entire industry.

Again, see above about one corner. And you're right, the ABS doesn't work with the jakes. The ECM, however, will kill the jake when a wheel starts sliding. As I pointed out ^up there in another post, oftentimes the engine will cut out the jake before the driver even knows there was wheel slipping. I for one, refuse to pretend like every driver out here is at the least common denominator skill level. I've some lengthy posts on managing traction on here, written for guys who have the experience to use that knowledge. Nobody has said to use the "HURR... DURR... throw on some jakes on sheer ice" techniques deployed by the clueless.

This part is true. I would add though, that if one slipping wheelset cascades into a full slide, that's running entirely to close to traction limits. Meaning to fast for conditions and too slick to be using the jake. Good point on the diff lock, too. Unless it's just totally trashy, I usually leave it unlocked for the early warning of one wheel slipping, and then lock it up if needed. If it's bad enough for chains, for example, the diff lock is going on and staying on. Same for wet ice.

Are jakes intrinsically more dangerous in slippery conditions? Sure, in the same way that operating a truck is also. Every tool has a time and place to be used, but some others pretend as if any jake usage in less than perfect conditions is a death wish, and that's simply not the case.