Safe to use engine brake on slippery wet roads?

Retarders are not a good idea on a slick surface, it can stop your drive wheels and cause loss of control. I had the Jake stop my drives on ice, it wasn't much of a problem on a straight road, I just had to catch the wheel speed back up to my ground speed but in a curve it could have caused a big problem.

 

In general, it's not a good idea. The problem is that you're slowing the truck without slowing the trailer, so the trailer is pushing against the tractor and if anything gets out of alignment, jacknife is likely. This is magnified if you're in an auto that will drop you a gear or two when the engine brake is first engaged.

In practice, if you ease into it - transmission in manual, start on low and let things settle out before going to the next stage - it's fine. But you're MAINTAINING speed, not losing it. I'd also switch it off before entering curves.

There's also a question as to what constitutes a "wet road".

 

Just wet, I used it all the time, but as soon as the road spray went away, I turned it off. Depends greatly on the condition of the engine brake. For example, a Mack I drove had an awesome engine brake, while some barely make a fluffer. Besides, if it's slippery, you shouldn't be going fast enough for the engine brake anyway.

 

Do not use on slick/slippery roads. Slow and steady gets you where you need to be, if need be. Sometimes it’s worth it to check the weather report first, wait out the storm and save a run for another day.

 

Eh depends on road conditions and what you are doing, usually use one or the other, holding back on a hill stage 2 on the jake is usually fine unless you are heavy enough to use 3 to keep from sliding, around town I use the service brakes more and leave the jake off though

honestly experience is the only way to learn when to use what

 

That's a bit subjective. Driver skill, terrain, other weather conditions, and driver habits are of more importance.

I use my Jakes all the time (more so between shifts in the truck stop), even on ice.

 

I used mine on ice and everything, if the wheels locked up the computer would cut the engine brake off. If you have an older truck I'd just say run it at a lower setting if you do use it and pay attention to your speedometer

 

off when slick.

 

You don’t want to use it on icy or slippery roads. The reason is because the of the axle differentials. They are designed to let the wheels spin at different speeds for going around corners. On dry pavement all the wheels have the same traction. When you turn on the engine brake all the wheels get the same braking power.

On snow or ice each wheel could have different traction. When you turn on engine brakes puts the braking power to drive axles. The differentials will then work against you because they will apply all the braking power to the wheels with the least amount of traction.

You can see this in action at truck stops in the winter. You will see truck in parking spot stuck because all the power is applied to the drive tires with the least amounts of traction. One tire or set of duals will spin and the other 3 will not move. That’s how the differentials work against you in snow or ice.

The skidding or spinning tires always want to come to the front and lead. If you spin drive tires they will want come to the front of truck and you will have a jackknife if you don’t do anything.

When you use jack brake in snow or ice if you differentials put all the power to tires with least traction. They will spin slower because they lost traction. They are now skidding and they will want to come to the front and you might jackknife if you don’t do anything. You basically are starting your own jackknife. Lots of drivers says it ok probably because they never had it slide on them. It come down to how much traction they have.

You can tell it starting to happen because you will have engine brake on and your RPMs might be at say 1300 or something. Then all of a sudden you see and hear your RPMs drop to idle but you speed did no change. Your sliding the drive tires now and better react by turn brake off.

I don’t understand why people would run engine brake when it’s slippery. The goal is to get down a hill without an accident. All 10 brake will do much better then trying to use just 4 brakes/drive tires. I don’t think a driver can say they are trying to save the brake wear. That’s kinda crazy in my opinion vs an jackknife that would be crazy expensive.