Originally Posted by NowGo
Thanks for the link Old Biscuit. This thread definitely evolved into a debate
, and any technical information is much appreciated. As a result of the evolution to debate, at some point I will prepare a bit of a dissertation as to my logic behind this mod, then all can take it or leave it as they desire. Meanwhile I am watching for the valuable technical input I am seeing.
Thanks again Old Biscuit
First off, I respect everyone’s opinions and their right to choose their own methods. For what it is worth, this is the logic and history behind my desire for this mod. Everyone can make their own choices.
Second, sorry for the long post.
I base my logic on my trucking experience. I have held the Canadian equivalent of a CDL (Class 1 in Canada) since 1978. I haven’t trucked for years, but when I did I hauled oversize/overweight loads up to more than double the non-permitted legal weight. This included mountainous travel in the Rocky Mountains as well as trips up the old Alaska highway, with steep grades far beyond what we see on public highways today. I have many stories. I have experience with Detroit, CAT, Mack, and Cummins engines, including experience with both exhaust brakes and engine brakes. Enough of that.
Engine brakes on trucks NEVER activated the stop/brake lights.
Using the engine brake on level ground (such as but not limited to city travel) comes with the responsibility to provide drivers behind me with an indication that this is occurring. When bobtailing with a truck (when the engine brake is capable of the most significant reduction in speed), I would tap or apply my service brakes gently or ride ever so gently to activate the stop/brake lights. This is what I plan to do where the stop/brake lights are not activated by the engine brake. I also turn on my signal lights to indicate a lane change, the truck or coach doesn’t do that for me either.
I am not pursuing this mod due to the fact that I use the engine brake all the time, although I do use it almost always, just as many other truckers/ex truckers do. If I use it city traffic it is on low setting, using my foot on the throttle to stop it from engaging so I can coast, just as I did with a semi. As to the indications to the drivers behind me, the low setting does not provide a dramatic reduction in speed. However, again I do acknowledge that drivers behind me need to be advised of speed reduction, and I have the service brake pedal for that.
I am particularly focused on the use of the engine brake to control speed on descent of long grades. There are runaway lanes on long grades for a reason, and I have no intention of using one. My coach has a GCWR of 64,000 lbs, and while that is not up to loads the semis are hauling, it is definitely enough to garner respect.
When rounding a curve at travelling at highway speeds to see traffic stopped or travelling at very slow speeds I activate the hazards, at least temporarily. I always did this when trucking and I do this whether I am in my coach or my four wheeler. This notifies the drivers behind me that something is going on up ahead, “pay attention”. I note that drivers behind me often take the cue and do the same. I am aware of various laws that state hazards cannot be used when moving. I prefer to avoid an accident.
When descending steep grades IMO experienced truckers will reduce the speed of their trucks to a speed which they believe will allow the engine brake to control the speed, or at least very close to it, with very few service brake applications, only as required. They will accomplish this initial speed reduction with the engine brake. The target speed can be dramatically less than the rest of traffic. Speeds of 30-40 miles per hour are not uncommon when using the engine brake to control the speed of a heavy unit on a descent.
This is where hazard lights come in. The trucks will activate the hazard lights to warn driver approaching from behind. (They also do this as they pick up speed when entering a highway with no acceleration lane.)
I am thinking others on this post may have been travelling through the mountains in the granny lane with their four wheeler only to break the crest of a hill and see a truck descending at a very low speed with the hazards on. Hazard lights gave you the heads up, then a quick lane check is required to see if the hammer lane is clear, then a quick lane change to avoid running into the semi that is descending the hill.
My coach has 6 stop/brake/tail lights. When using the hazards the top two flash. When I apply the service brakes the top two stop flashing and all 6 come on (no flashing). That’s ok as it provides drivers behind me with an indication that I have applied the service brakes. BUT, what happens if the engine brake applies all 6 in a steady on state? As I travel down the grade at a significantly reduced speed the drivers behind me see only the activated brake lights. I prefer to give them a better “heads up”.
Next, if during that descent I am required to provide emergency braking to slow the coach quickly (such as when Bambi jumps out in front of me), that notification to drivers behind me is not provided. The stop/brake lights were on before the rapid reduction in speed from the emergency braking, and they stay on with no change. What about the notification to the drivers behind me?
Most importantly, by using the engine brake method I have described I have cool brakes with full capacity when Bambi comes along.
The primary reason for minimizing service brake use on grades is to stop them from overheating. Hot brakes are reduced in their effectiveness. If not managed, the heat can result in the total loss of braking power.
Remember the runaway lanes? Over those decades I referred to earlier I have made mistakes, smoked brakes, and scared myself sufficiently to learn my lesson.
Minimizing the use of service brakes increases their lifespan. Owner/operators are acutely aware of this. Brakes are not cheap. Service brakes will always be used, at low speeds and at redlights, and periodically as required. I have never seen brakes becoming glazed from lack of use due to using engine brakes extensively, but I have seen them become glazed due to overheating. (I have experienced them becoming packed with snow, requiring periodic deliberate application to clear the snow).
Now let’s look at towing a trailer with electric brakes. I have a Tekonsha proportional brake controller. My brake controller is activated by the stop/tail lights. Braking power applied to the trailer brakes is then determined by inertia. However, initial application of the stop/brake lights does provide initial power to the trailer brakes. The way my coach is currently set up this occurs when the service brakes are applied OR the engine brake is activated. When monitoring the brake controller (visual indication of amperage) I can tell you that the brakes are activated a lot, with minimal change in inertia. I want ALL my brakes cool for the time I really need them. My trailer brake controller is set correctly. Reducing the setting on the brake controller to zero while descending grades eliminates the availability of the trailer brakes for emergency braking. I do not want to have to manually engage my trailer brakes in that situation.
As to safety (forgive me as I digress), thanks to the many posters on this forum (GasMan, Gary Jones, and others) I have been able to install side signal lights midway up the side, on the front side, and have my mirror markers function as signals. My point is… I believe building a coach that is 43-45 feet long with absolutely NO side signal lights is far, far more of a safety issue than building coaches and deeming it is necessary to have the engine brake activate the stop/brake lights.
As it currently stands, my engine brake activates my trailer brakes and defeats my hazards. I do like the idea of having a switch so I can choose how the engine brake affects stop/brake lights. Until that can be accomplished, IMO the engine brake has no business activating stop/brake lights.
I quote BonS in post https://www.irv2.com/forums/f112/sto...ts-586047.html
page 5 = I want the choice so I can implement my driving/braking strategy based upon the circumstances on hand.
I am thankful we can all choose to make our own decisions and my intent is not to fuel debate, but I did feel some of what I had to say might be helpful.