This method works by: first, choosing the correct gear for the hill; second, allowing the truck to speed up to the maximum safe speed as it descends the hill; third, applying the brakes hard to slow the truck down 5 mph; and then repeating this process to the bottom of the hill.
Thanks, everyone, for the encouragement, advice, and sightseeing hints! I guess I'm more nervous about this than I thought, but you all made me feel a bunch better! I'm going to load the sightseeing into my Palm Pilot!
Clattertruck, how do I know which is the correct gear as we begin our descent? And is "maximum safe speed" the posted speed, or am I to go somewhat slower based on conditions?
Just a reminder - if you see the "rig" in my original posting signature sometime during the last 2 weeks in May, for the sake of you and your loved ones, move the heck out of the way!
Regards,
Michelle
* This post was
edited 05/07/08 02:30pm by mitch5252 *
2008 Fun Finder X-160
2006 Toyota Sienna Limited
Equal-i-zer Hitch
Prodigy Brake Controller
Clattertruck wrote: What is key here is not the speed drop, this will depend on weight, grade and other factors, but air pressure, you have got to get the application pressure high enough to get all your brakes working.
Notice what this says about air pressure. The tests were done on trucks with air brakes, not the conventional hydraulic brakes of cars and vans.
First, I think you should be comfortable using the engine braking. Even if you have an automatic transmission, you can use '1','2' or 'D' to limit your speed when going down hill. I like to choose the gear that lets me drive with a light touch on both gas and brakes. There should be enough hills in Tennessee to give you experience with engine braking.
I have driven roads where even '1st' in an SUV was not enough, ones where I wanted to keep my speed below 20 mph. Often that was because of the curves or roughness (on gravel), more so than the steepness itself. In those conditions I do use something approaching that 'snub' method. Hard enough braking to slow down, but without locking the wheels or brakes, and then letting speed pickup. Maximum speed depends on conditions - road width, curves, roughness, traffic, etc.
The alternative is to partially apply the brakes all the way down. Apparently this is more likely to to cause over heating.
Anyways, as long as the trailer is not too heavy, engine braking should be enough on most paved highways. The van has disk brakes front and back? ABS as well? Traction control? Brakes on the trailer?
The more you use engine braking the easier on the brakes. When towing I go slower than the speed limit. With a four-speed auto trans I tend to run in third or second gear, never in overdrive going downhill. If the rig requires constant heavy braking you need a lower gear. Some experience will let you know what feels right. Do the braking before you get into a turn and not in a turn.
If you do not have a transmission cooler your Sienna trans may overheat both up and downhill (using engine braking). Coolers are not expensive. The Sienna is not a heavy duty towing vehicle no matter what a salesman may say.
Clattertruck
2008 SD F450 PSD 6.4L CC 4X4 DRW, Lariat Auto trans 4.30 LS, 2008 Snowriver 108 truck camper. Jeep Unlimited Rubicon as toad.
To get some good engine braking you will need to shift down to get the rpm up in the 3500 to 4500 range or similar to the rpm seen when climbing a similar hill. Second or third gear will probably be the choices. Low or first gear would only be for the steepest (10%+) grades with hairpin curves.
I tend to slow more than the recommended 5 mph. More like 10 to 12 mph. I run the speed limit and as I start to go over I will get on the brakes to be 5 or 10 under the limit.
Also if you slow for a curve, do the braking before you enter the curve. And as you exit the curve and the road straightens out you might feel like you are crawling along and get tempted to touch the gas but don't. Let it coast back up to speed and then back on the brakes as needed.
You will see others riding the brakes, try to avoid their example. As long as you do not get in a hurry you will be fine.
2001 F150 SuperCrew 5.4 Lariat Offroad 4x4 Tow Package 4.10 Truetrac
2006 Keystone Springdale 249FWBHLS
12K SuperGlide, KGE3000Ti 2.3kw rated 2.6kw max
Frank's voltage booster, Prosine 1800 powered by 4 GC2 batteries
The route is fine and yes you will have some grades, but if I read that route correctly - Red Lodge to Cody is a snore. She's not going down the Beartooth nor the Chief Joe. The route out of Red Lodge is MT308 via Bearcreek and Smith Mtn Mine to Belfry, which after the initial climb is pretty much flat. From Belfry MT72 south to WY120 is basically flat, slight rise 6% to top of Skull Creek Pass and a downhill into Cody.
* This post was
edited 05/07/08 06:35pm by Ozimo *
Yada, yada, yada - my correct braking having driven the Bighorns for more than 30 years is this:
a) Always stop at the top. Put the transmission in neutral with the brake on or just turn it off. Don't forget to disengage the hand brake before heading downhill;
b) Put the vehicle in one gear lower than when you came up;
c) Brake evenly into the turns;
d) Let off the brakes otherwise and try not to over rev the engine; Pumping the brakes works better than a hard push. You'll smell the toasted brakes on a warm day right before Shell Canyon - another good place to stop;
e) If you need to stop, do so - just not in the middle of the road;
f) Try to not be ahead of a BIG truck - if you see one heading downhill stay at the top for 15-20 minutes until they are down safely;
g) There are runaway lanes and if you need to use it don't be ashamed - use them!
Ozimo wrote: b) Put the vehicle in one gear lower than when you came up;
A great guideline, but those with massively powered TV's must remember that it's entirely possible to haul *up* a grade at a speed that would be suicidal to go down the other side at.
Ozimo wrote: b) Put the vehicle in one gear lower than when you came up;
A great guideline, but those with massively powered TV's must remember that it's entirely possible to haul *up* a grade at a speed that would be suicidal to go down the other side at.
Well, they are no more "massively powered" than the double tanker rigs that drive that mountain without any problems every day.
Ozimo wrote: A great guideline, but those with massively powered TV's must remember that it's entirely possible to haul *up* a grade at a speed that would be suicidal to go down the other side at.
Well, they are no more "massively powered" than the double tanker rigs that drive that mountain without any problems every day.
I think you need to re-read my response.
If you compare the power to weight ratio of a pickup truck (especially the 3500 series trucks) pulling a trailer to a semi hauling a full load, you'll see that the pickup truck is vastly ahead of the curve.
The pickup truck / TT can therefore pull a grade without loosing any speed, whereas the semi will loose considerable speed. One must keep that into consideration when coming down the other side - just because the pickup truck / TT combo roared up the hill without ever dropping a single MPH it doesn't mean it's safe to come down the other side without slowing down (and downshifting) at the top despite the fact.
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