Downhill Braking Advice

[Mollysdad]

Originally Posted by kscherzi

Just looked it up, its a 9 1/2% grade for the first six miles, pretty substantial.

Yes, but the OP was talking about a trip to Colorado. If he's concerned about I-70, there's no grades more than 7%. From Denver it's up, up, up until the Eisenhower tunnel, then down, down, down until you're back on Earth.
Once you've done it, you'll not fear it again. The road wanders around, so parts are 7%, parts are flat. Although the sign says "7% grade next 12 miles" doesn't mean it's 7% everywhere.

[OTRA15]

Originally Posted by kscherzi

Just looked it up, its a 9 1/2% grade for the first six miles, pretty substantial. Not to mention the 1,000 foot cliff off to one side. I tried to keep it under 35 mph, and in low gear, either 2nd or 3rd out of 10 gears. This is one situation where the 3.5 Ford ecoboost engine just doesn't have enough breathing capacity to give a lot of braking assist. I let it rev to 5,500 rpm even. Lesson I learned is to pump and hold, pump and hold, and be prepared to pull over before things get out of hand. Maybe I'll try first gear next time.

Then 35 MPH was probably too high IMO. Sounds like 15-20 MPH might have worked, or pull over as you said, with flashers on. Things get out-of-hand only if the driver chooses to permit it.



On a cross-country trip decades ago, I witnessed the aftermath of a semi roll-over, after he had obviously lost control on a long downhill. The rig was a crumpled tangle of metal . . . as if a giant had taken a Tonka Toy and shredded it, then wadded it up into a ball.

Emergency personnel were all over, looking confused and dazed . . .

. . . powerless even to find the driver, let alone remove whatever was left of his body.



That image is clear in my mind whenever I know -- well ahead of time -- of a steep downhill grade ahead.

Preparation . . . preparation . . . preparation . . .

Happy trails,

Peter

[pjshier]

"Things get out-of-hand only if the operator permits it."

Mostly... that is IF the operator includes margins to compensate for when the systems a prudent operator relies upon decide to take a cr*p at the worst possible moment. I second your admonition for starting down slower and lower for just such a reason.

Ask me how I learned this with tractor brakes on fire hurtling down Thompson Pass when the trailer brake controller took a dump. 2nd gear with brake assist seemed reasonable for a load of welding rod. Totally inadequate without the brakes. I should have considered a margin and used 1st.

In the big scheme, the temporary crawl down the grade with the engine loud is not a big deal unless it is a daily commute or you are getting paid by the hour.

[Ray Eklund]

Never drive DOWN faster than your going UP... is my rule of thumb.

There are a number of very experienced Mountain DIVERS (aka drivers) on the Forum. If any say it is an easy transition from the top of the pass and down... they have a Diesel Truck towing and even then... it is doing the Tango in a body cast.

My preference is staying in the right lane if there is NOT an 18 wheeler. Then the center lane. Keep under 55mph. When your vehicle and trailer are accelerating... I lay hard onto the brakes... get the speed under control and then try to maintain a comfortable speed in short spurts. Five miles per hour over your comfort zone is a good time to pull back the speed increases. Ten mph on a grade that is not as steep coming up will make things... exciting. Not any fun.

There really is no easy way. Riding the brakes is like cooking an egg slow and possibly getting hot brakes and little braking. If your trailer is pushing you while braking, you may want to consider manual braking for the trailer in short spurts when laying on the to vehicle's brakes. Avoid any trailer tire lockups. Not all work together and adjustments are not in perfect harmony.

Smelling burnt and hot brakes are from vehicles in front of you. Those behind you will smell yours. I have seen smoke coming out of 18 wheelers rear four wheels in the past. Not a good sign for you to... pass them, either. Hot brakes and rubber are a bad combination.

I never have seen much in the way of out of control vehicles on Eisenhower Pass / I-70. The truck run off sand will tell you if any have needed to use it to stop.

Monarch Pass... is the scariest of all. The King of Colorado's passes. I do not recall any 18 wheelers using that route in southern Colorado.

Take your time down. If you lose your hydraulic tow vehicle brakes, your transmission may already be in a high gear an unable to down shift. Emergency manual tow vehicle braking and use your manual trailer brakes as a last resort.

This is just my opinion from steep grades in the West. I have a F350 Diesel and even then you need to concentrate about traffic in front, sides and behind every second of other traffic. They are just as focused as yourself.

Get some practice on the first ups and downs out of Denver and learn. It is like fly fishing... it takes a little experience. Take a deep breath, make it down and the rest of I-70 is easy! If you find this very intimidating... Wyoming's I-80 from Cheyenne to Laramie will get you UP... and take a different route into Colorado.

One PLUS. Your gas mileage will increase...

[sirtate]

Remember how to calculate kinetic energy...

E=1/2MV^2...

So to dump 20mph from 70 down to 50mph is 2400 units of heat... (Simplified math... Mass is the same, and units are equal... Watts will use m/s, but the result will be the same ratios)

Which is almost the same as stopping the vehicle from 50mph... (2500 units)

Your brakes need to turn that energy into heat, and then dissipate that heat...
If your speed allows them to do that, they won't heat up.

If you keep dumping speed, those Watts (energy units) will add up and heat the brakes quicker than they can cool...

Give them the best chance, by not loading them up with all that energy...
Slow down...

[Doc Foster]

Originally Posted by Adventure.AS

I find that using 'cruise control' helps keep the downhill speed under control. The TV computer downshifts as required and cuts off fuel flow to keep the set speed. If you use your TV brakes this turns off cruise control, so be ready to reset it if required. I also use the hand controller on the trailer brake controller to keep tension between the trailer and TV on steep sections.

Maybe I had an older Tundra, but when using cruise control downhill with my old Tundra (2012?) it would NOT keep the speed under control when towing.

[OTRA15]

Originally Posted by Doc Foster

Maybe I had an older Tundra, but when using cruise control downhill with my old Tundra (2012?) it would NOT keep the speed under control when towing.

"Cruise control" typically does not apply the brakes to reduce excessive speed IMO.



Does anyone have a CC which does apply the brakes if necessary?

Peter

[GCinSC2]

Originally Posted by kscherzi

I learned this coming off Towne Pass from Death Valley, a nine mile long 6% to 9% constant downhill. Had to pull over as truck brakes started to fade and were really hot. Checked the trailer wheels and they weren't even that warm. Proved the truck was doing all the work. Something else to think about.

kscherzi,

This description, hot TV brakes but trailer brakes were not hot in this situation.

Have you inspected/adjusted brakes and tested your brake system functioning?

I carry an IR temp gun and this is exactly what I'm looking for when I pull over for a rest stop. Braking makes heat. No brakes, no heat.

Gary

[Adventure.AS]

Originally Posted by OTRA15

"Cruise control" typically does not apply the brakes to reduce excessive speed IMO.



Does anyone have a CC which does apply the brakes if necessary?

Peter

Vehicles with ACC (Adaptive Cruise Control) use the brakes as well as the throttle and transmission to slow you on a descent.

[KK4YZ]

Originally Posted by Doc Foster

Yes, slow down and downshift before you crest over that mountain pass. Never let your speed get out of control. Use breaks when you have to, but downshift.

In addition to the above, while primarily using engine to control downhill speed, brakes should be applied momentarily, not constantly, if needed. Riding the brakes downhill will cause heat buildup which could lead to brake fade/failure.

[aftermath]

Gibson, I am pulling a 25FB with my 2017 Tundra but before that, I also towed it with an '08 Tundra. I have over 45k miles doing this. I live in the NW and have been up and over many steep passes. Did the Death Valley pull, the North Cascades pass, one in Canada that still scares me and, the most challenging one in Wyoming that goes through Ten Sleep down to Buffalo.


You have gotten great advice here. I would add that you should make sure your trailer brakes are in working order. Your controller should be a proportional conroller to avoid what someone has mentioned earlier. The Tundra has very heavy duty discs all around so fading should not be a problem.
Don't resist the downshift. I will be in third on steep hills and even have used 2nd a time or two. Keep the speed down, use tow haul, stay in the right lane and use your flashers if you feel the need. Most passes are not all that long. I brake to reduce the speed down and then let off the brakes. I also remember by dad telling me to always brake in the straight sections and not in the corners. This makes more sense to me now that I am pulling a trailer.


You are going to be fine, especially now that you are thinking about this. I think the Tundra and 25ft Airstream is a very good combo.

[OTRA15]

Originally Posted by Adventure.AS

Vehicles with ACC (Adaptive Cruise Control) use the brakes as well as the throttle and transmission to slow you on a descent.

Thanks Ray.

Guess that dates me!

Peter

[Mollysdad]

Originally Posted by OTRA15

"Cruise control" typically does not apply the brakes to reduce excessive speed IMO.



Does anyone have a CC which does apply the brakes if necessary?

Peter

No. My Tundra cruise control disconnects if the RPM gets too high.

[Ray Eklund]

Lots and lots of opinions going downhill.

Google: Mountain Passes in Colorado Ratings

This will also include Colorado's Dangerous Roads, etc....

Pick your poison pill among these on your route. Truckers are sparse in these tough grades up and especially down. There is a long record of reasoning here, why the professionals have to be prepared for the tougher grades. Many prefer other options.

Experiencing Utah's I-70 Passes is a good place to get some practice. I advise anyone needing some experience to practice here before Flaming Gorge in Utah and Wyoming attempts.

Wyoming's I-80 from Cheyenne to Laramie is a good climb and a steep drop into Laramie for practice. Then comes Park City, Utah and an interesting mix from Wyoming into Utah.

Towing an Airstream or any trailer up and down any steep grade is dangerous for many drivers. I can list a number of people I would not want to be a... passenger. This is not for amateurs and bloviators. You can get hurt, seriously once the panic begins.

Nancy and I have driven so many dangerous passes that if we can... we avoid them. Not because we panic, but the wear and tear on the vehicle is severe. There are roads, like the Black Canyon of the Gunnison... if you just drove your vehicle down to the river... you wished you had... NOT. A trailer in tow... you are DEAD. (I believe there is a sign that says not to have a trailer in tow... but some people cannot read, very well when traveling.)

Maybe someone may want to put a group of Airstream owners together and hit the TOP 50 Passes in the Western USA. Maybe the Top 20 would sort out the amateurs and those who really understand you are taking on a lot of risk if not comfortable with your two vehicle and trailer's ability to maintain a safe speed.

Many have a Tow Vehicle that is light weight to the weight of the Airstream pushing them down just due to gravity alone on the up and downs of the Interstate Highways of Kansas.

You are playing with... fire and gasoline. This is not smart traveling if you are unprepared to take on a lot of risk. The actual number of people towing a trailer in the Rockies and chose a tough Pass are far and few. I find them Dangerous if you are not prepared.

If your trailer is overloaded. Your tow vehicle is inadequate. Your experience is sparse in these situations... think three times or more. There are easier ways to avoid these passes.

These are only my OPINON. I do this all of the time. I am not a white knuckle driver. Often these Passes are in my way and I am taking risks if my tow vehicle, trailer and awareness is not 100%. Be careful.

Look at the front brakes at the bottom. If you see red or other powder sticking to the wheels... that is your brakes wearing down.