Engine brake when raining? Yes or no?

[C.Martin]

I'm riding with those guys that expressed the conservative approach. I can throw out formulas of 9* the sq.root. of the tire pressure for hydroplaning speed. And so on and so forth. The bottom line is...

Engine Brake...no anti-lock protection
Cruise Control...no anti-lock protection
Normal Braking...anti-lock protection.

Which of those do you want to avoid?

Now throwing out blanket statements about what you can and cannot do is ludicrous. Each situation will depend on slope (grade), weight, velocity, turn loading, wind effect, depth of water, tread, texture of the surface, surface contaminants like oil, sand, clay slurry... I have had B737's totally loose brake effectiveness at relatively slow speeds... like we were on ice with no more than a damp runway with rubber buildup, and non-groved surface...incidentally, anti-lock helps prevent you from spinning like a top, it doesn't mean you will necessarily stop. I guarantee a B737 weighs more than any four motorhomes put together on landing...and that is on level ground.

Do what you want...but I would be hesitant to build up someone's expectations based on far reaching blanket statements.

Hopefully, if you don't feel written guidance is worthy of following...maybe the little hairs on the back of your neck will save you from taking a situation too far. I take advantage of anything I can when it comes to safety.

I'm sure if you ever fly on my jet...you'll be glad to know I didn't learn to fly on iRV2 ....

Ventana....fun
T-37,T-38,C-21A,C-141B,B-727/737/757/767/777,MD-11, A319/321... haven't departed a runway into the grass yet!!!...work.

[Ivylog]

I use mine but do not engage unless I am going straight and try not to use both the brakes and the Jake at the same time.

[Sky_Boss]

If the owner's manual says you shouldn't use compression/exhaust brakes or retarders in slippery conditions I suspect it has some basis in experience. Just because some haven't had a problem doesn't mean it can't happen to them in the future.

I know there are those that think they know it all or that every warning is to make lawyers happy. They can do as they choose. It is for each of us to sort out opinions and use our brains on what we choose to do.

The general subject of use of these devices generally falls into 2 thoughts. One is to use them all the time and the other is use as needed. Based on what I see on IRV2 discussion threads I t think the majority fall into the belief that they should normally be set to on.

I think there needs to be a little more judicious use of them. As I see it it is kind of like using a good tool at the wrong time. Its use can take away the control you need at the most critical time. Put aside the slippery pavement issue for the moment. You are cruising along at 65 MPH on a flat road with the EB on and you have a blow out. In the process you remember to add throttle like you should but at some point you go to zero throttle and the EB kicks in. That could be a problem that you didn't see coming and could be disastrous. I speak from experience from something similar happening to me.

IMO, use of the EB should be done with thought especially at cruise speeds in any condition let alone questionable ones. You need 'em, use 'em. YMMV

[Skiddy]

Originally Posted by C.Martin

I'm riding with those guys that expressed the conservative approach. I can throw out formulas of 9* the sq.root. of the tire pressure for hydroplaning speed. And so on and so forth. The bottom line is...

Engine Brake...no anti-lock protection
Cruise Control...no anti-lock protection
Normal Braking...anti-lock protection.

Which of those do you want to avoid?

Now throwing out blanket statements about what you can and cannot do is ludicrous. Each situation will depend on slope (grade), weight, velocity, turn loading, wind effect, depth of water, tread, texture of the surface, surface contaminants like oil, sand, clay slurry... I have had B737's totally loose brake effectiveness at relatively slow speeds... like we were on ice with no more than a damp runway with rubber buildup, and non-groved surface...incidentally, anti-lock helps prevent you from spinning like a top, it doesn't mean you will necessarily stop. I guarantee a B737 weighs more than any four motorhomes put together on landing...and that is on level ground.

Do what you want...but I would be hesitant to build up someone's expectations based on far reaching blanket statements.

Hopefully, if you don't feel written guidance is worthy of following...maybe the little hairs on the back of your neck will save you from taking a situation too far. I take advantage of anything I can when it comes to safety.

I'm sure if you ever fly on my jet...you'll be glad to know I didn't learn to fly on iRV2 ....

Ventana....fun
T-37,T-38,C-21A,C-141B,B-727/737/757/767/777,MD-11, A319/321... haven't departed a runway into the grass yet!!!...work.

and what was done before anti lock brakes. just slow down in inclement weather, rain or even wind. use your EB to keep you going slow. just my .02

[Superburban]

The recommendation of not using any type of retarder in inclement weather, goes back to the late 60's at least, when the various types of retarders were gaining popularity.

[Domo]

Originally Posted by Crasher

Let me tell you what can happen when you drive on a rain slick road with the exhaust brake engaged. I was going south out of Corpus Christi in our then new 1996 36' Discovery just after a heavy downpour that had let up to a light mist. It was on a two lane asphalt road and I had just crossed a bridge over a canal. I was going 40 mph and let off the power for a slight curve after the bridge. The EB engaged and immediately shifted to a lower gear. When that happened, the rear wheels broke loose and I found myself sliding broadside taking up half of the other lane with an oncoming car. I instinctively turned into the slide and applied a little power which disengaged the EB and shifted up a gear. The coach came back into my lane and the car went past. It scared the cra* out of me, my wife and 14 year old grandson. That was 12 years ago and all of us remember it like it was last week. Now whenever we're driving in the rain, my wife reminds me to turn the EB off along with the cruise control. We like safety better than stupidity. So the next time some unknowing expert tells you that running with the EB on when the roads are wet is not a problem, tell him he doesn't have a clue as to what can happen.

Sadly, it seems so many remain convinced that they know better than the engineers that built and tested the systems we drive, nor do they listen to people that have had such close calls as you have. Thank your wife every time she reminds you - that's teamwork and it helps keep you alive!

Thank goodness you survived and didn't hurt anybody else at the same time.

[C.Martin]

Crasher,

Glad you made it out of that situation and thanks for sharing. Important wake up call for the rest of us.

I have read a few OTR trucker forums. You have to remember they drive thier rigs daily and are very familiar with them. They actually shift gears manually in most cases...so they aren't surprised by the 6 speed allison deciding to downshift on them when not expected. We can all be ready with hand on EB switch...as we let off the accelerator, but unlike the pro trucker, again, we don't know exactly at what point Allison is going to down shift. Apparently, Jacob's of "Jake Brake" makes thier systems to be interconnected to the normal ABS system...so that the Engine Brake is turned off if a skid is detected by the ABS system. I haven't a clue if Freightliner/Spartan use this feature on the Motorcoach Chassis.

I think this is a great discussion. If it doesn't make anyone convinced to wait for the rain to subside, or select a less mountainous route...at least the little voice in their head will make them think twice. Can't ask for more than that.

[Superburban]

For the most part, I keep the engine brake off, and hit the switch when I want it. I can't think of any situation where the few seconds it takes to flip the switch, will change anything. I feel its much safer, and easier to turn it one when needed.

[C.Martin]

Originally Posted by Superburban

For the most part, I keep the engine brake off, and hit the switch when I want it. I can't think of any situation where the few seconds it takes to flip the switch, will change anything. I feel its much safer, and easier to turn it one when needed.

With the exception of carbon-carbon brakes like the B767-300 uses...most brakes fade when they get really hot. Wheels also get hot...which can lead to melted fusible plugs or tire blowouts. The engine brake is used to prevent having to apply prolonged applications of the normal brake system to compensate for weight and downhill grades. This saves the normal brakes from failing when needed most. That said...although not really designed for everyday use...I think it's good practice to use them and remind yourself frequently where the switches are and have muscle memory of how to operate the controls. I don't think once a year going thru the mountains of W.NC. is going to keep my skills up. I use them pulling off exit ramps, stop and go sometimes... just try to make sure I use them a couple of times each time we go somewhere. Stay comfortable using them when needed. I think on many coaches the switch may not always be located in view or in an intuitive location. Mine are on the left side console not in my normal viewing area and located in the same row as the tag axle dump. A lot of good that will do you going down a steep grade.

There it is...now I see my Engine Brake ->->->->

[Superburban]

If the switch is in a bad ergonomically position, then I think it is even more ideal to keep it off, and turn on when wanted.



Like I said, I doubt that few seconds lost in flipping the switch, is not going to change anything. But if one gets so used to it always being on, and forgets its on when they hit rain, and does not realize its on until they lift their foot, and go into a slide, the few seconds it takes to realize its on, and turn it off, can be too late.


I think it would help if the manufacturers have it default to off, when the engine is turned off, and the driver has to turn it back on after they start the engine. Or do like the Military, and have the Jake controlled by a foot pedal.



Just my 2 cents, after driving many different vehicles, since the 70's, and investigating several accidents. Yes, the majority of my experience is with tractor trailers, and recovery vehicles, which have different weight distributions almost every time they are driven. But I still think the principles, and driver training are the same.

[Sky_Boss]

Originally Posted by Superburban

If the switch is in a bad ergonomically position, then I think it is even more ideal to keep it off, and turn on when wanted. ....

That is my biggest gripe for both of my coaches! While the one we just got is "better" than the 2006 one, it is still out of eye sight. I would gladly give up on cup holder to move things forward.

[Superburban]

Thats crazy. I guess that's one advantage in having an old rig, I have moved most of the switches on mine, including the exhaust brake to the right side of the dash. Also, changed the most important ones to paddle switches, instead of the rocker style.


Thats why I did not care for driving school buses, I do not like the switches on the left, and all the same.

[docj]

Originally Posted by Sky_Boss

That is my biggest gripe for both of my coaches! While the one we just got is "better" than the 2006 one, it is still out of eye sight. I would gladly give up on cup holder to move things forward.

With all due respect, I've memorized the feel of all of my console switches and never look at them while driving. The Jake, wipers, cruise control and mirror controls all have different shapes and "feel" and I have no need to look at them. IMO taking your eyes off the road to look down/sideways introduces the possibility of drifting out of your lane.

[Skiddy]

doesn't you all's have a light on the dash when it's on? that's usually my visual/reminder of if I need to turn it off or not.