Descending down a mountain

[zackyboy3rs]

1st timer hauling North Carolina mountains. Little nervous about the descent on the way back to flat land. I will be towing my parents TT which is 7500lbs total weight. Give me any tips or pointers. Tow/haul button on, gear down? Bend over & kiss my a$$ goodbye or what? Thanks

[bud121156]

I was more concerned about the engine turning ~4000 RPMs going up the mountain. I backed off, and kept the engine closer to 3000-3200 and was much more comfortable.

[CampingN_C_]

You'll be fine. I still stress out every time we go to the mountains, guess I always will.
Let us know how you do.

[hddecker]

zackyboy3rs wrote:
Not knowing the route is my biggest problem. The planned route is 421 west to Hwy 16. Same route coming home. 421 I am familiar with but 16 I am not.

Of corse, I have a brake controll & have it adjusted for this trailer.

Thanks

Don't let not knowing a route bother you, pretty much every time we travel we will be on roads we have never seen before. We use Interstates sparingly, every trip is an adventure.

Just pay attention to the highway signs as they apply to your rig and don't let anybody behind you pressure you into doing something your not comfortable doing.

When someone gets on my backside, towing or not my answer to them is you may as well get around me because the closer you get the slower I'll go.

[opnspaces]

Here's my reply to a similar question from a few months back.

We will tell you to drop a gear or two to go down the grade without having to ride the brakes. That works well, but if you've never done is before you will probably not be comfortable without a tachometer (RPM gauge) on the dash to tell you that you're not damaging the engine. Here's what I would suggest if you do have a tachometer and a gasoline powered vehicle.


Go driving with just the tow vehicle and no trailer. Go find a bit of road that you can accelerate to 60mph without endangering yourself or others.
Safely stop the vehicle and pull the shifter down into the lowest gear. Accelerate until 15 - 20 mph and then shift up one gear on the shifter.

Can you drive 60 mph in that gear without getting within 500 to 700 RPM before the red or orange markings on the tachometer? If not shift up until you can drive 60 mph while still being below the red or orange markings on the gauge. The idea is to find the lowest gear (2nd, or 3rd) that you can drive at 60 without letting the tachometer get to the orange or red markings. Once you find this gear you know that you can downshift to this gear on a hill and not damage your engine.

Let's say your truck is like my Suburban that I can run 65 mph in 2nd gear without hitting the orange or red marks. When I crest a big hill like the grapevine I just slow down to about 50 mph. I then shift the transmission selector to the 2 position and take my foot off the accelerator pedal and away from the brake pedal and just start to coast down the hill.

As I go down the hill the speed will slowly start to increase. But, since I'm in 2nd gear it behaves like I have my foot on the brakes which I don't. When the speed climbs up to about 58 mph I put my foot on the brakes and firmly press to slow the vehicle down to 50 mph again. Once I get to 50 mph I take my foot off the brake and start coasting again.

I usually only have to touch the brakes three maybe four times for a hill the size of the grapevine. While it may seem like this is stressful it is usually just the opposite. With the transmission in a lower gear I don't have to watch the speed like a hawk. Instead it just goes down the hill as if I'm dragging a parachute behind me and only speeds up slowly.

The ultimate idea here is to use tow/haul mode and put the truck in a lower gear so the engine does the braking.

[DiskDoctr]

spoon059 wrote:

If you need to brake, I believe it is preferred to stab your brakes hard and quick rather than ride the brake pedal. The idea is that a quicker and more sudden brake...

No, DON'T stab your brakes hard and quick. It could lead to a loss of control and can create a hazard for motorists behind you.

Ease on and continue to firm and slowing, then abruptly let off the brakes and allow a cooling interim if possible.

Easing on allows the entire rig to load up the towing connections, brakes, drive axles, etc in a controlled manner, then apply controlled and firm braking.

You absolutely want to avoid "panic braking" in most situations, especially downhill steep grades and especially on sharp turns.

Reduce your speed before reaching sharp turns and switchbacks. Try to avoid strong braking on turns, which can cause loss of control, especially when slippery.

We have 9% grades here, though rare, and I downshift my 4Runner with about 6.5k on it at times.

Are you using a wdh? Make sure you do! Without, the front end can get light, break loose in a sudden rain on a hot day, trigger abs, and start shooting across the double yellow on a turn.

[Community Alumni]

Passin Thru wrote:
BB is 6% for 5 miles, some interstates are 9%, but no more out west. Never saw anyone descend up a mountain!

All "interstates" must be AASHTO compliant and restricted to 6% grade. Waiver can be issue from the Federal Highway Administration for mountainous regions, but restricted to 7% with speeds under 60 mph. The Eisenhower system is designed to move military equipment across the country quickly and efficiently. When moving heavy or sensitive equipment, grades are important.

[dee74]

Great advice here. Just remember to go as slow as you want and do not let others influence your driving and do not ride the brakes, got brakes do not works as well.

[zackyboy3rs]

Not knowing the route is my biggest problem. The planned route is 421 west to Hwy 16. Same route coming home. 421 I am familiar with but 16 I am not.

Of corse, I have a brake controll & have it adjusted for this trailer.

Thanks

[DustyR]

Golden_HVAC wrote:
Hi,

You have a 2500 series TRUCK! Not some little 1/2 ton thing that should not be towing 11,000 pounds. The trailer is only in the 6,500 pound range. I would guess that you will have electric brake controller. Without the electric brakes, yes kiss your self goodbye, that would be crazy!

Leaving it in the tow haul mode, then lightly tap the brakes at the top of the hill should downshift it a gear. Then compression braking should handle most of the speed that can build up while going down a steep grade.

Yet you never mentioned going through the Rocky Mountains, or down any well known 11 mile long 7% steep grade, just a short run on the freeway. What you are planning is pretty simple. A truck rated to tow and stop a 12,000 pound travel trailer (with electric brakes) and you will only be towing about 6,500 - 7.000 pounds. No big deal at all!

Fred.

X=2
I agree with Fred. Tow/Haul Mode and the tow vehicle must have a brake controller for the trailer yours probably has a integral one if it has the tow package. Most grades on major highways have a suggested descent speed at the top, brake and then gear to hold that speed and you will be safe.

[tomman58]

The thing to remember when going downhill is it isn't the truck as much as the trailer. On the higher % grades it is important to realize that the trailer will want to "push" the truck and some manual braking may be needed on the trailer.
This is "not" the case with you and your light trailer.

[Beer_Belly]

In my '06 Silverado, I'd drop it into Manual Mode, 2nd gear going down a 13% grade.....my 2013 Silverado I use Tow/Haul Mode.....it will down shift on it's own....I think it senses when you're braking and need help slowing down

[Jayco23FB]

I have a 2007 2500HD with the 6.0L and 3:73. Leave it in haul mode and let the transmission do it's job of downshifting to assist on the downhill drive. I Just drove through MT, WY, ID, CO and UT on some big hills with my 6500# TT. Wolf Creek pass in CO was fun and the trani did a great job.

[Golden_HVAC]

Hi,

You have a 2500 series TRUCK! Not some little 1/2 ton thing that should not be towing 11,000 pounds. The trailer is only in the 6,500 pound range. I would guess that you will have electric brake controller. Without the electric brakes, yes kiss your self goodbye, that would be crazy!

Leaving it in the tow haul mode, then lightly tap the brakes at the top of the hill should downshift it a gear. Then compression braking should handle most of the speed that can build up while going down a steep grade.

Yet you never mentioned going through the Rocky Mountains, or down any well known 11 mile long 7% steep grade, just a short run on the freeway. What you are planning is pretty simple. A truck rated to tow and stop a 12,000 pound travel trailer (with electric brakes) and you will only be towing about 6,500 - 7.000 pounds. No big deal at all!

Fred.

[Passin_Thru]

BB is 6% for 5 miles, some interstates are 9%, but no more out west. Never saw anyone descend up a mountain!

[Terryallan]

coolbreeze01 wrote:

bud121156 wrote:
IIRC, its 6% for 6 miles.

6% isn't really considered a grade here. Be careful and have fun.

Like as not. Your interstate has the same grade %. The interstate max is the same across the US. Now IF you want to talk about OFF the interstate. We can go there as well.