Gas verses Diesel Tow Vehicle

[gypsydad]

Originally Posted by SCOTTinNJ

Just think of your TVs rear wheels trying to resist forward momentum with the trailer freely pushing against them.

Going straight downhill on dry pavement, fine.
Going straight downhill on wet pavement, likely fine.

Now add a turn and think about the side forces on those rear tires. In slippery conditions it's better to have a bit of tension on that hitch (by applying trailer brakes).

If anyone has ridden a motorcycle they may understand. You only have so much traction. It can be used for acceleration/deceleration and turning. If you overuse it for one you will have nothing left for the other.

Never really considered the difference in wet driving vs dry when using engine brake, but it makes sense. I did look at my manual and sure enough; your right! I also noted when in auto mode, the engine braking and downshifting is automatic when needed to maintain selected speed. I use this a lot going up/down in the Rockies and find it much less stressful then when I drove my F150 pulling my 25'. Thanks again for pointing this out...Forum is a great place to learn what you don't know!

[RandyNH]

Yup, same principal I learned at 18 when I bought a new 5.0L Mustang 5 speed, drive it home in the snow on the highway and downshifted to aid in slowing, did 3 - 360s and came to rest on the edge of the breakdown lane, no damage and learned that the more wheels you have involved in slowing the mass down the better you'll fair, whenever the road condition is questionable.

[franklyfrank]

Originally Posted by gypsydad

Never really considered the difference in wet driving vs dry when using engine brake, but it makes sense. I did look at my manual and sure enough; your right! I also noted when in auto mode, the engine braking and downshifting is automatic when needed to maintain selected speed. I use this a lot going up/down in the Rockies and find it much less stressful then when I drove my F150 pulling my 25'. Thanks again for pointing this out...Forum is a great place to learn what you don't know!

I don't know about your set up but my trailer brakes engage simultaneously with the truck brakes. Not only that I can apply them independently. That gives me plenty of options to avoid spinning out control.
However if someone is that inexperienced not to reduce their speed on a slippery roadway to avoid sliding out of control it won't matter what kind of equipment they are driving, they will buy the farm.

[jcl]

Originally Posted by franklyfrank

I don't know about your set up but my trailer brakes engage simultaneously with the truck brakes. Not only that I can apply them independently. That gives me plenty of options to avoid spinning out control.

Exactly the point as to why you should use your service brakes, because none of that applies to your exhaust brake. Especially for those of us who don’t live in Florida, where road conditions perhaps aren’t as variable.

[Tuco]

Originally Posted by gypsydad

Never really considered the difference in wet driving vs dry when using engine brake, but it makes sense. I did look at my manual and sure enough; your right! I also noted when in auto mode, the engine braking and downshifting is automatic when needed to maintain selected speed. I use this a lot going up/down in the Rockies and find it much less stressful then when I drove my F150 pulling my 25'. Thanks again for pointing this out...Forum is a great place to learn what you don't know!

This is just another instance of not having real world experience. Please, does the manual say don't use your service brakes, downshift or let off of the throttle in wet conditions because you "might" lose control? Learn what the exhaust brake can and can't do and how it performs in different configurations and situations. Let your common sense determine if its advisable, just like you do with anything else while towing (or not towing).

[pteck]

It is an important point to understand how various braking effects actually work. Living in the west, mountain roads are a regular occurrence for me, including switchbacks with steep grades.

It's always important to rely on engine brakes to avoid overheating the brakes when in the mountains. Yet when entering a sharp downhill curve, I will almost always check the brakes before entering the curve in order to settle the whole rig. With the Prodigy brake boost function, this allows the trailer to apply its brakes first, putting the hitch in tension. It's good practice and especially important when in rainy and low traction conditions so the trailer is not surging on the tow vehicle entering a curve, potentially risking a jackknife situation.

Full time 4WD is another benefit under engine braking. Instead of a single rear axle trying to slow down the whole rig, all wheels of the tow vehicle are engaged under engine braking, lending more stability.

[pteck]

Originally Posted by Countryboy59

What vehicle these days comfortably seats eight?

Rhetorical question. But my Lexus LX570 (aka Lexus Land Cruiser) does. I have kids that are perfectly content to be back in the 3rd row with their own space. It also means I don't need a separate van from my tow vehicle when family visits. I have gone on long 2400 mile trips under tow with my extended family of 6. Doesn't get more comfortable than having a full size SUV for this. With power for days to climb the Sierras, Klamath, and Cascade mountian ranges.

I do want more fuel range though. Fixing that this month by adding an auxillary tank.

[KK4YZ]

Originally Posted by RandyNH

Yup, same principal I learned at 18 when I bought a new 5.0L Mustang 5 speed, drive it home in the snow on the highway and downshifted to aid in slowing, did 3 - 360s and came to rest on the edge of the breakdown lane, no damage and learned that the more wheels you have involved in slowing the mass down the better you'll fair, whenever the road condition is questionable.

As a Mustang owner I can tell you the real lesson is don’t drive that thing in the snow! 😀 I use mine as a fair weather toy.

[SCOTTinNJ]

Originally Posted by pteck

It is an important point to understand how various braking effects actually work. Living in the west, mountain roads are a regular occurrence for me, including switchbacks with steep grades.

It's always important to rely on engine brakes to avoid overheating the brakes when in the mountains. Yet when entering a sharp downhill curve, I will almost always check the brakes before entering the curve in order to settle the whole rig. With the Prodigy brake boost function, this allows the trailer to apply its brakes first, putting the hitch in tension. It's good practice and especially important when in rainy and low traction conditions so the trailer is not surging on the tow vehicle entering a curve, potentially risking a jackknife situation.

Full time 4WD is another benefit under engine braking. Instead of a single rear axle trying to slow down the whole rig, all wheels of the tow vehicle are engaged under engine braking, lending more stability.

This is all worth repeating. Very good.

[DewTheDew]

Originally Posted by SCOTTinNJ

This is all worth repeating. Very good.

Catching up on this thread I was also wanting to point out that if you are towing in 4WD (which I do when it is wet) then I believe engine or exhaust braking would add braking force to all four tires similar (though not identical) to the service brakes. Probably with less control, however, but I suspect it would have to be REALLY slippery (more than just normal rain) to create a problem.

[jcl]

Originally Posted by DewTheDew

Catching up on this thread I was also wanting to point out that if you are towing in 4WD (which I do when it is wet) then I believe engine or exhaust braking would add braking force to all four tires similar (though not identical) to the service brakes. Probably with less control, however, but I suspect it would have to be REALLY slippery (more than just normal rain) to create a problem.

That is true, and a possible approach as long as you are not towing (when the exhaust brake is most likely to be used). You give up control even then, because of giving up ABS and stability control, and there is always the issue of increased tire wear with no centre diff, but the biggest issue is that if towing, the hitch is now in compression, not tension, unless you are manually applying the trailer brakes during the descent.

That can all be done, but it is common to hear about new diesel owners (and some long term ones) noting that they don’t ever have to touch their brakes now that they have an exhaust brake. That is worrying.

[franklyfrank]

Originally Posted by jcl

That is true, and a possible approach as long as you are not towing (when the exhaust brake is most likely to be used). You give up control even then, because of giving up ABS and stability control, and there is always the issue of increased tire wear with no centre diff, but the biggest issue is that if towing, the hitch is now in compression, not tension, unless you are manually applying the trailer brakes during the descent.

That can all be done, but it is common to hear about new diesel owners (and some long term ones) noting that they don’t ever have to touch their brakes now that they have an exhaust brake. That is worrying.

FWIW, I have a simple rule. When on the road and cought by a normal to heavy rain event I slow down to where I fell comfortable and in control. If it goes on too long I park and wait it out. After all I have all the creature comforts needed right behind me.
Sleet, Snow, Ice my Airtsream stays parked period.
Being retired and Airstreaming only for pleasure, having all the time in the world I choose not to torture myself.

[rgg123]

Originally Posted by franklyfrank

FWIW, I have a simple rule. When on the road and cought by a normal to heavy rain event I slow down to where I fell comfortable and in control. If it goes on too long I park and wait it out. After all I have all the creature comforts needed right behind me.

Sleet, Snow, Ice my Airtsream stays parked period.

Being retired and Airstreaming only for pleasure, having all the time in the world I choose not to torture myself.

[emoji106]

[pteck]

Originally Posted by DewTheDew

Catching up on this thread I was also wanting to point out that if you are towing in 4WD (which I do when it is wet) then I believe engine or exhaust braking would add braking force to all four tires similar (though not identical) to the service brakes. Probably with less control, however, but I suspect it would have to be REALLY slippery (more than just normal rain) to create a problem.

Just to clarify, I was talking about full time 4WD (with center diff) being an advantage when towing at speed in marginal weather. These types of vehicles (usually more off-road oriented SUVs) can utilize all driven/braked wheels full time, with all stability and ABS systems on.

How one is to use 4x4 part time systems in these conditions is different. Because there's no center diff, it wouldn't be recommended to use in rain or outside of very low speeds. In any turn or maneuver, without the center diff, it will force slippage of tires in itself. Which can be dangerous to traction, as sliding friction is generally lower than static friction, potentially initiating a TV slide.

Lower speeds, higher transmission gear engine braking, and/or gentle application of the brake pedal may be the better answer.

[tjdonahoe]

Originally Posted by pteck

Just to clarify, I was talking about full time 4WD (with center diff) being an advantage when towing at speed in marginal weather. These types of vehicles (usually more off-road oriented SUVs) can utilize all driven/braked wheels full time, with all stability and ABS systems on.

How one is to use 4x4 part time systems in these conditions is different. Because there's no center diff, it wouldn't be recommended to use in rain or outside of very low speeds. In any turn or maneuver, without the center diff, it will force slippage of tires in itself. Which can be dangerous to traction, as sliding friction is generally lower than static friction, potentially initiating a TV slide.

Lower speeds, higher transmission gear engine braking, and/or gentle application of the brake pedal may be the better answer.

How do you get 4 wheel drive of any sort without the center diff....?even our Toyota Venza has 2 center diffs....

[Adventure.AS]

Originally Posted by tjdonahoe

How do you get 4 wheel drive of any sort without the center diff....?even our Toyota Venza has 2 center diffs....

A part-time 4WD usually has a central transfer case, which turns the front and rear axles at the same speed and that can be engaged when needed. But it is not a differential that would, for example, allow for faster rotational speeds of outside wheels in a turn.

[r carl]

There is transfer cases that act like an open diff and transfer cases that lock so front and rear drive shafts only turn at the same speed.

[Tuco]

Originally Posted by jcl

That is true, and a possible approach as long as you are not towing (when the exhaust brake is most likely to be used). You give up control even then, because of giving up ABS and stability control, and there is always the issue of increased tire wear with no centre diff, but the biggest issue is that if towing, the hitch is now in compression, not tension, unless you are manually applying the trailer brakes during the descent.

That can all be done, but it is common to hear about new diesel owners (and some long term ones) noting that they don’t ever have to touch their brakes now that they have an exhaust brake. That is worrying.

There is only one use case for the exhaust brake I have found and that is this.

"If you plan to use the service brakes, consider using the exhaust brake first"

In all my years of using said exhaust brake I have never even come close to losing traction (or control) in wet or dry conditions (solo or towing). Granted that the system in my truck only has one mode, manual.

[gypsydad]

Originally Posted by Tuco

There is only one use case for the exhaust brake I have found and that is this.

"If you plan to use the service brakes, consider using the exhaust brake first"

In all my years of using said exhaust brake I have never even come close to losing traction (or control) in wet or dry conditions (solo or towing). Granted that the system in my truck only has one mode, manual.

Amen brother! 48K miles now in our 2017 F250 with no issues; for the trip over to Borrego Springs from Austin last week, we never used the exhaust brake as mostly flat land driving...going from Borrego to San Diego Thursday, we did use the exhaust brake as the pass out to Julian was a bit steep and somewhat slippery in places due to snow/ice...we just took it slow and safe. The exhaust brake is very helpful in traffic and steep grades for sure.

[slowmover]

Originally Posted by Tuco

After all the years you have owned that truck you still haven't installed an exhaust brake? Because if you had you wouldn't be saying some of the things you have in this post. (you cant use the exhaust brake in the wet? Added braking adds nothing? What?)

You really shouldn’t comment about that which you neither understand and have failed to research.