Hill climbing for new guy

[elibrown]

Hello everyone. I have a quick question about hill ascending and descending.
I have pulled trailers of all shapes and sizes in my day, including our 32' travel trailer for the last 10 years. We purchased our first-Class A, a 2022 Thor Miramar 35.2 with the 7.3 late last year. We have been out on a few short trips but are planning to go to St. Augustine Florida area late May. Our trip will take us on I24 northwest of Chattanooga. I have been thru this are several times and know that there is a decent short grade near Monteagle Tennessee. For those of you who have been thru here, any tips or suggestions on how to traverse properly? Will my coach handle this incline/decline without any problems?

 

[stripit]

Having fulltime traveled for 8 years and then doing the winter get out of the cold times have come across many hills/mountains that slowed us way down. I always just put on the 4 way flashers, stayed in the far right lane and did not try to floor the acclerator pedal, just let the rig climb up at whatever pace felt right. Folks will go around and you will get to your destination safe and sound. Biggest problem is getting stuck behind a really slow semi truck and your not able to pass quickly so you just follow him up.

 

[CharlesinGA]

Set it to tow haul, on the downgrade if you start going too fast just hit the brake. The computer will downshift the transmission. Still too fast? tap the brake again, it will downshift again.

If you have an M position on the gearshift, you can select it and manually shift up or down using the +/- rocker switch on the gearshift lever.

In D you can limit the top gear using the +/- switch. Each press of the minus reduces the top gear by one, and each press of the + adds to the the top gear by one.

I copied the Tow/haul mode from the manual, online.

Tow/Haul Mode

WARNING: Do not use tow/haul when the road surface is slippery. Failure to follow this instruction could result in the loss of control of your vehicle.

To activate tow/haul, press the button on the gearshift lever once. The TOW HAUL indicator light illuminates in the instrument cluster.
To deactivate the tow/haul feature and return to normal driving mode, press the button on the gearshift lever again. The TOW HAUL light deactivates. Tow/haul can also deactivate when you power down your vehicle.
The tow/haul feature:

• Delays upshifts to reduce the frequency of transmission shifting.
• Provides engine braking in all forward gears, which can slow your vehicle and assist you in controlling your vehicle when descending a slope.
• Depending on driving conditions and load conditions, may downshift the transmission, slow your vehicle and control your vehicle speed when descending a hill, without pressing the accelerator pedal. The amount of downshift braking provided varies based on the amount the brake pedal is pressed.

The tow/haul feature improves transmission operation when towing a trailer or a heavy load. All transmission gear ranges are available when using tow/haul.

Charles

 

[Mountain high]

I drove the I-24 grade back in 1982 from Atlanta through Chattanooga to Alabama. So I entirely missed that grade. The grade is 5%. That being known, it's steep.

Just control your downhill speed. Go slow and stay slow. There's some steeper 6% to 7% grades out on a couple other Interstate Highways, but then 5% is still steep. Colorado on I-70 through the Rockies where we live has up to 7% grades. I've seen runaways on one with smoking brakes. Too often it's tempting to stay with the flow. Just don't and you'll be fine. Use the ramps if needed.

Don't be the guy from Las Vegas traveling at the speed limit recently coming down our steep Colorado Interstate grade and losing control of his RV. He blamed it on hitting a pothole. It was reckless driving per the LEO.

Going up just ignore the traffic behind you. I followed a motorhome from Florida with a Toad traveling up Monarch Pass in Colorado on the east side doing 6 to 7 MPH for several miles. It happens in Colorado. I'm use to it. So are other locals.

"Westbound Interstate 24 from the Monteagle Summit has a vertical descent of 778 ft. over 4 miles. The reported grade for the westbound descent is 5% for 4 1/2 miles."

You'll be fine.

 

[Ray-IN]

Plenty of good advice. One thing not mentioned, is when descending start out slow and maintain your slow speed to the bottom. You can always speed up some if you feel safe to do so, slowing back down to a safe speed on a downgrade is much harder than it sounds. That is the entire reason those steep downgrades have runaway truck/RV ramps.
We travel in our home on wheels, hurry is not in our vocabulary.

 

[Skookum]

From the Washington State DOL's Commercial driver's guide...It works for motorhomes like it works for trucks, although, this is also speaking to heavy vehicles with manual transmissions and air brakes, although many of the same concepts may be useful even for a gas motorhome with hydraulic brakes and an automatic transmission.

Me and the other half are right lane bandits. Everyone with their hair on fire can just go around. I also follow the commercial driver rule of using my flashers when my speed drops 10-15 miles per hour below the posted speed limit to war other drivers that I'm slow-moving.

Pick a good gear, and just let 'er eat....that how I do it. Keep an eye on water temp and trans temp, and your pyro if you have a diesel and it isn't modern.

 

[CharlesinGA]

I have driven I-24 thru Monteagle quite a few times in the car and the Motor home, but never pulling the trailer. There are plenty of lanes for folks to go around you, and from Monteagle down onto the Cumberland plateau (and coming back up it east bound toward Chattanooga) is straight, easy climb or decent. The other side, headed down, toward Chattanooga is a little different, having some curve to the downhill and requires a little more attention. Gear it down.

Coming thru Nashville........ I won't, its crappy and the roads are horrible. On I-24 Eastbound (heading south actually) when I get to TN 155, which is the Briley Parkway, I take the Briley Pkway east and circle around town, past Opryland, past the airport at which point the last mile or so before I-24 on the south side of town is where the limited access ends. Its just a couple of traffic lights and then head south/East on I-24 toward Chattanooga. It adds about 5 miles to the trip but the parkway is six lane limited access and very smooth and usually not busy.

Charles

 

[Gary RV_Wizard]

The engine and transmission computers will get you up the hills just fine. Leave it in Drive and push the go-pedal down and try to maintain a steady speed. You will almost surely be slower than car traffic, so stay to the right and don't expect to pass anybody.

For the downhill side, make sure you do NOT speed up when you level out at the crest; start downhill at the speed you want to go all the way down. Use tow/haul mode as described earlier in this thread and use the brake pedal as needed BEFORE speed gets too high for safety.

 

[elibrown]

Thanks everyone for taking the time to reply and offer the advice. Looking forward to putting it to use!!

 

[HikerBob]

When I gone up steep hills my speed would be about 35 mph with a rpm of 3800. You will run into slow trucks going slower and the empty trucks will be passing you by.

 

[udidwht]

A general rule...

Whatever speed/gear you were going up in let that be your max/gear going down.

 

[Mountain high]

A general rule...

Whatever speed/gear you were going up in let that be your max/gear going down.

Yes, that was an old theory when I was a kid (I'm 65). Today's trucks with both gas and diesel have much more power than they did back then. Use a lower gear to go down than up.

"Some use this rule for older trucks: use the same gear going down a hill that you would need to climb the hill. Newer trucks have streamlined designs, more powerful engines and can navigate downhill with less friction and air drag. So, newer trucks must use lower gears to go down hills than they do to go up. Taking this into account, along with getting to know your vehicle will let you know what’s appropriate."

Driving Downhill – How to Stay Safe in One of the Most Dangerous Driving Conditions

Driving downhill is one of the biggest tests when taking your CDL. Mountain passes, driving with a full and/or heavy load, and steep grades can be some of the biggest contributing factors to making driving downhill a stressful

unitedworldtransportation.com

 

[Utclmjmpr]

Speed is NEVER a priority when climbing,,,getting to the top with everything still operating normally is..>>>Dan

 

[Larry N.]

Speed is NEVER a priority when climbing,,,getting to the top with everything still operating normally is..>>>Dan

Same for going down...

 

[Gary RV_Wizard]

The old "same gear" adage was also more relevant with manual transmissions. Changing the gear selector on an automatic is more like advice to the tranny rather than a command. Plus the modern tow/haul mode of the Ford automatic manages hill climb/descent quite nicely.

 

[Ray-IN]

Gary brings up a good point. The Allison transmission of this decade in controlled by a TCM=transmission control module. The TCM monitors engine RPM and if the diesel engine reaches the redline, the TCM will command the Allison upshift to lower engine RPM. The driver has no control over this event.
That leaves the driver with only the service brakes to reduce speed to a safe level. Once a slower speed is reached the Allison TCM will allow it to once again downshift to that lower gear that was selected, where an exhaust brake is once again effective.

However, I don't know if that applies to the Ford F53 drivetrain.

 

[Skookum]

To Ray's point, those new to diesels should find a copy of the engine owner's manual and read up. Diesels have governed speeds, "redlines" for those who are familiar with gas engines. A diesel can have two different governed speeds depending if it's under load (producing power) or engine braking.

For example, the governed speed under load of a Cummins B6.7 is 2600rpm, the TCM may let it run out to 3200rpm while engine braking, and that's still within a safe engine speed. The reason being, without fuel, a higher braking horsepower is achieved at the higher RPM with the turbo brake and/or engine brake ("Jake"). The TCM will demand an upshift if your foot returns to the accelerator.

 

[Gary RV_Wizard]

However, I don't know if that applies to the Ford F53 drivetrain.

It does, and also to any other automatic transmission of the last 4-5 decades. Older trannys may have had arbitrary upshift points, but with the advent of electronic controls in engine & tranny it became a cooperative effort.