Downhill Driving December 15, 2020, 01:33:33 pm Another rookie question. Tomorrow I’ll be driving the LD down our mountain. We live at 5,600 ft. elevation and the road to get down is a 1,400 foot elevation change in about 2.5 miles with some pretty good twisty turns. Should I put it in Tow/Haul mode? I’m thinking I should drop it into 2nd gear for most of the hill as I do the Subaru. Where should I keep the RPMs? 1 Likes
Re: Downhill Driving Reply #1 – December 15, 2020, 02:10:08 pm This is not LD specific advice, but from four months and lots of mountain descents in numerous class C RVs.Downshift to the gear that minimizes your brake usage, you should rarely need to touch the pedal. Will you be going slow? Yep. 3 Likes
Re: Downhill Driving Reply #2 – December 15, 2020, 03:00:44 pm Are you talking about the Sherwin grade on the 395 going towards Bishop? The numbers you gave sounds like it may be. A truck driver friend camped with me up thereabouts (French camp) when I first got my LD and taught me how to negotiate the grade. Basically, he had me put it into 2nd gear and brake when the rpms hit 4,000. I averaged only about 25-30 mph which felt really slow and lots of other RVs and trailers passed me, but it did save the brakes. We even saw a RV at the bottom of the grade with a blowout, likely from overheated brakes. It had flew by me near the start of the descent doing about 60 mph. 4 Likes
Re: Downhill Driving Reply #3 – December 15, 2020, 04:04:14 pm Quote from: YHung - December 15, 2020, 03:00:44 pmAre you talking about the Sherwin grade on the 395 going towards Bishop? The numbers you gave sounds like it may be. No, this is the grade from my house to the valley below in the community that I live.
Re: Downhill Driving Reply #4 – December 15, 2020, 04:13:00 pm I love the tow mode in our rigs in the mountains. This summer I crossed the Rocky Mountains 4 times and the sisikyou mountains 4 times as well. I really came to love this drive train. Tow mode really minimized braking. I’m also conservative descending mountains from driving old heavy trucks. If the traffic wasn’t bad and I I found the sweet spot (mph/rpm) sometimes never had to use the brakes. 1 Likes
Re: Downhill Driving Reply #5 – December 15, 2020, 05:05:49 pm Tow/Haul is a setting that changes the automatic shift points for the transmission. It does not change operation if you manually put the trans in second or first. Now, 1400 feet in 2.5 miles is an 11% grade. When I am descending the east side of Teton Pass, it is roughly a 10% grade for about 2.5 miles. I am towing when I cross the Pass, so I have my Subaru pushing me along. I put my rig into first gear at the top. When the RPM's reach 5000, I brake to 3000 RPM, then release the brake. Yep, I am going really slowly. Yep, even going slow, it will heat the brakes a bit. Nope, my brakes are not stinky at the bottom.There is a similar but longer grade just northeast of Pagosa Springs, CO. When I am going southwest coming down the grade, second gear can manage the speed, but the grade is long enough that my transmission heats up. When it reaches 225, I pull into a turnout and park, leaving the engine running to keep fluids circulating. When the trans has cooled to below 200, I will continue. Depending on how warm it is, I may need a second stop.The key is to be in a lower gear before you NEED to be in a lower gear, and to manage your vehicle to preserve your braking ability. Don't worry about going slowly. Put on your four way flashers, and ease your way down.Ken F in NM 2 Likes
Re: Downhill Driving Reply #6 – December 15, 2020, 05:06:09 pm I start the grade slowly and then tap the brakes to allow for downshifting until I find the right gear which is typically third on a moderately steep grade - six speed transmission. I anticipate limited braking on curves so I don't have to go too slow.I think engine speed is maybe 4000 or so. Depends on the hill, of course. Frank 2 Likes
Re: Downhill Driving Reply #7 – December 15, 2020, 07:01:08 pm The Owner's Manual has details on downhill driving. On steep grades when towing, I gear down before the speed builds, letting the engine reach 4000-4200 RPM and then brake hard to scrub off 5-10 MPH and then let the speed build up again before braking again. Riding the brakes can cause them to overheat. I want to minimize the time the brakes are applied, allowing the brake rotors the maximum amount of time to cool before the next breaking event. Overheated brakes can fail and possibly warp the brake rotors.This method has work fine for a 125,000 miles, most while towing a Jeep.For extreme downhill grades, having someone drive the toad isn't a bad idea.Larry 2 Likes
Re: Downhill Driving Reply #8 – December 15, 2020, 07:15:38 pm I live in Colorado and I took the RV Driving School class in my LD as soon as I got it. My instructor advised me that I should activate Tow-Haul every time I drive my RV. Essentially the load of the RV on the truck means that the truck is always hauling something. Furthermore, I never drive on a flat surface in my region. I have had years of experience driving in the mountains and I have found that the tow-haul feature takes care of most of the work. In fact, whenever I feel as if I am not in control, I realize it is because I forgot to activate the tow-haul. Jeanine 2 Likes
Re: Downhill Driving Reply #9 – December 15, 2020, 07:19:54 pm Rule of thumb is pick a gear that you use the brakes minimally and only for a few seconds. If you’re riding the brakes gear down. If you aren’t using the brakes at all gear up. 2 Likes
Re: Downhill Driving Reply #10 – December 15, 2020, 07:22:03 pm Quote from: Jeanine C - December 15, 2020, 07:15:38 pmI live in Colorado and I took the RV Driving School class in my LD as soon as I got it. My instructor advised me that I should activate Tow-Haul every time I drive my RV. My RV driving school instructor advised the same.
Re: Downhill Driving Reply #11 – December 15, 2020, 08:36:20 pm Here is a description of what Tow-Haul does."The tow/haul mode changes a vehicle's transmission shift patterns. Pulling a heavy load requires a lot of power. The tow/haul mode reduces shift cycles. Depending on the truck, it may also boost torque and engage an engine braking mode to help drivers maintain control while driving up and down hills.In general, the tow/haul mode changes shift points to higher RPM limits. This helps you keep moving as you haul your trailer. As you go down hills, you may notice that your transmission will downshift earlier than normal. This allows the transmission to help you slow down and saves wear and tear on your brakes, too."Our 2007 LD has Tow-Haul. I see no reason not to use it, I do frequently.Charles
Re: Downhill Driving Reply #12 – December 15, 2020, 08:54:13 pm Quote from: Jeanine C - December 15, 2020, 07:15:38 pmI live in Colorado and I took the RV Driving School class in my LD as soon as I got it. My instructor advised me that I should activate Tow-Haul every time I drive my RV. Essentially the load of the RV on the truck means that the truck is always hauling something. Furthermore, I never drive on a flat surface in my region. I have had years of experience driving in the mountains and I have found that the tow-haul feature takes care of most of the work. In fact, whenever I feel as if I am not in control, I realize it is because I forgot to activate the tow-haul. JeanineDo you gear down also or leave it in Drive?
Re: Downhill Driving Reply #13 – December 16, 2020, 09:21:18 am Don't claim to be an expert here Greg, but this is what I do in our 2010 RB. Always approach steep downhills slowly and make sure you are in TOW/Haul if you have it. As mentioned in previous previous posts by Larry/Joan and other long time RV's , the key to entering a safe speed downhill is entering at a proper speed. Slower! Out of courtesy and safety, put on your hazard flashers if 45 MPH or slower. This will also warn those behind you that you are slowing and to use caution.Just before starting the decent at a speed of about 45 - 60 mph, I slowly depress the brake pedal (do not pump the brakes) until I feel the brakes engage, then release the pedal. With the TOW/HAUL feature the coach will downshift one gear and the RPM's on a steep downgrade will usually be around 4000 RPM. Each time you depress the brake pedal in the manner described above the coach will downshift another gear slowing the coach and raising the RPM. Some extreme downgrades for us have produced RPM in the 4,400 range, but that has not been a problem for the engine and tranny.Once you have started your decent with TOW/HAUL engaged and flashers blinking, concentrate on maintaining a slower speed, even if that entails using the brakes slowly and firmly, then releasing the pedal. If you can safely turn into a pull out because of traffic behind you, do so and rest yourself and your LD for a bit while the brakes cool. Hopefully I explained IMO what I do most of the time. I have been daydreaming occasionally (often) and find myself screaming downhill and having to recover. NOT a good plan.You have a beautiful LD. Take your time with her/him and your LD will take care of itself.Most respectfully,Tony R (aka codefour) 2 Likes
Re: Downhill Driving Reply #14 – December 16, 2020, 09:55:51 am RV driving instructors advising to put it in tow haul exclusively are taking the easy way out. TH is a useful setting on hills both down and up but using it 100% of the time will adversely effect your mileage. On long relatively flat stretches without a head wind TH isn't necessary. Leaving it in TH on 2 or 3% down hill stretches is not only unnecessary but counter productive. You will end up making your engine do what gravity could be doing for you.Having said that I'll admit to being an MPG freak and driving to maximize that number. Others may find it more relaxing to put their tranny in TH and leave it there no matter what.
Re: Downhill Driving Reply #15 – December 16, 2020, 10:45:45 am Greg, whether I manually shift down or let Tow/Haul manage the system, with brake activation as nicely described by Tony, depends on the situation. I find manual control to be certain, while tow/haul is less so. There is a grade on Rt 26 in Idaho near Swan Valley that calls for some downshifting. I know it well, I know the two curves involved, and I know Tow/Haul will handle it. As I begin down, I do as Tony describes with the brake, the rig downshifts, and when I apply some gas at the bottom, it shifts up. There is another grade approaching the place I camp near the Tetons with a short, steep grade and two sharp curves. Tow/Haul does not respond to it sufficiently. I slow at the top, drop it into 1st gear, and shift up when past the critical area.Respectfully, if you are in the driver's seat, you should not abdicate control to Tow/Haul unless you know it will handle things adequately. Anticipate what is needed. If manual control is appropriate, then slow and shift to the proper gear. Remember that it is much easier, and gentler on your equipment, to start in too low a gear and shift up when you are too slow, than to start in too high a gear and to try to slow and shift down when the speeds are climbing beyond comfort for the road.Ken F in NM 5 Likes
Re: Downhill Driving Reply #16 – December 16, 2020, 11:04:38 am "...in Idaho near Swan Valley"Hey, isn't Swan Valley where you get the square ice cream? 1 Likes
Re: Downhill Driving Reply #17 – December 16, 2020, 04:03:00 pm In my very younger days I drove heavy duty doubles from San Fransisco to Reno up I-80. From sea level to 7000 ft and back again. <smile> a paper route for the San Fransisco Chronicle. Did it off and on for two, three years. Working my way thru school. An old salt told me the speed you drive up the hill is the speed you use going down. Using the engine brake is safer then using the wheel brakes. Between you and me I never in any rush to get there - where ever there is. glen 3 Likes
Re: Downhill Driving Reply #18 – December 16, 2020, 04:39:37 pm Quote from: colddog - December 16, 2020, 04:03:00 pmIn my very younger days I drove heavy duty doubles from San Fransisco to Reno up I-80. From sea level to 7000 ft and back again. <smile> a paper route for the San Fransisco Chronicle. Did it off and on for two, three years. Working my way thru school. An old salt told me the speed you drive up the hill is the speed you use going down. Using the engine brake is safer then using the wheel brakes. Between you and me I never in any rush to get there - were ever there is. glen Jake brakes really make the downhills easy if used properly. I once lost mine in a seriously overloaded truck on a 6% grade hauling grain from Bonners Ferry Idaho to Central Ferry Wa on the Snake River. Had to strictly use gears like the old timers. It was a white knuckle ride with the smell of brakes permeating the cab. Didn’t know if I’d make it or not and was never so relieved as when I hit the bottom and saw the long straight flat stretch before you get to the river. Why was I so overloaded you may ask. Farmer I hauled for had us go around the scales on dirt roads which was SOP in Idaho in those days .
Re: Downhill Driving Reply #19 – December 16, 2020, 05:33:23 pm Quote from: Sawyer - December 16, 2020, 04:39:37 pmJake brakes really make the downhills easy if used properly. Jake brakes are only used on diesel engines and are outlawed in many areas due to the very loud noise the brake makes when in operation.Compression release engine brake - WikipediaUnless you own a diesel powered LD, a Jake brake is not applicable for our usage.Our V8 and V10 gasoline engines use the engine's vacuum to slow on descent and have no need to plug the exhaust.It's a lot quieter too.Larry
Re: Downhill Driving Reply #20 – December 16, 2020, 05:52:43 pm Quote from: colddog - December 16, 2020, 04:03:00 pmAn old salt told me the speed you drive up the hill is the speed you use going down. Good advice.Larry
Re: Downhill Driving Reply #21 – December 16, 2020, 06:19:11 pm Quote from: Larry W - December 16, 2020, 05:33:23 pmJake brakes are only used on diesel engines and are outlawed in many areas due to the very loud noise the brake makes when in operation.Compression release engine brake - WikipediaUnless you own a diesel powered LD, a Jake brake is not applicable for our usage.Our V8 and V10 gasoline engines use the engine's vacuum to slow on descent and have no need to plug the exhaust.It's a lot quieter too.LarryYeah I know. I got a bit off subject as I often do. I blame colddog for bringing up trucks. Did I ever tell you about the time........ LOLJakes being outlawed is news to me though. There’s always been certain parts of certain roads in town that prohibit compression brakes but outlawed altogether? Is that a California thing?Personally I love the sound of a Jake brake but that’s probably just an old truck driver talking. Brings back good memories.
Re: Downhill Driving Reply #22 – December 16, 2020, 08:04:32 pm Quote from: Sawyer - December 16, 2020, 06:19:11 pmJakes being outlawed is news to me though. There’s always been certain parts of certain roads in town that prohibit compression brakes but outlawed altogether? Is that a California thing?No, it's not a California thing, your favorite state to hate, they are usually prohibited by local ordinance that prohibits "Engine Brakes". AFAIK, no state outlaws them statewide.Larry
Re: Downhill Driving Reply #23 – December 16, 2020, 09:00:51 pm Greg, just a thought considering that's your go-to route North and West.After the 3rd time down the hill, you'll have it wired.safe travels.Joel 2 Likes
Re: Downhill Driving Reply #24 – December 16, 2020, 09:23:03 pm Quote from: HiLola - December 15, 2020, 08:54:13 pmDo you gear down also or leave it in Drive?Greg, the tow/haul takes care of the gearing down. When I use my brakes to slow down, the tow/haul responds and adjusts to my new slower speed. 1 Likes
Topic: Downhill Driving (Read 842 times)
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Topic: Downhill Driving (Read 842 times)
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