Down hill jake braking, what speed and gear do you use?

here it generally means in low range

 

that is a great rule of thumb

 

What happens on those steep ### downgrades that you never climbed up to? There are a LOT of places with a fairly gentle climb on one side, and a screaming descent on the backside. Cabbage Hill, Cajon Pass, several grades on I-15 in Utah, Fancy Gap. Also.... what if you climb Cajon Pass, or Tehachapi empty....then pick up 45k or so and head back down? Might be trouble. Doesn't totally negate the rule of thumb, but it IS something to think about.

 

you ALWAYS err on the side of caution, top gear low range to start with, don't over-use the brakes until you are clear about what the descent is like, if need be slow the truck to a near stop, or maybe even stop and select a lower, more appropriate gear and let the engine retarder do its job. Doing this will save your brakes for when you really need them. You can always sneak up gears if you over-estimated the grade of the descent. It is far easier to go up gears that go down gears on a descent, as soon as you throw the clutch, without lots of brake pressure the truck will take off

 

Well....*I* know this.... top end of low range might be a bit much...unless you absolutely WANT to slow down to 10-15 mph on the interstate. (There are a few 14-16% grades in Pennsylvania that might warrant this....but they are on state and US highways) I usually just start at about 35-40 (7th or 8th, depending on weight) on an unknown grade, and work from there. That being said, I do prefer to run US and State highways any time it makes sense to do it. Even if it does take a bit more time. I am rarely pressed enough for time that even a couple hours difference will hurt me. Plus, it's nice to get away from the mad rush of racing truckers once in a while.

 

Australia must be hillier than the USA

 

If you are new you need to develop a feel for grades. The best thing to do and I know this will piss some people off. If it says 55mph, put your hazard lights on, jake on, gear down, and do half the posted sign or the minimum speed limit if posted. So about 30 mph on your very first trip if you are totally new. Go down at a speed where you don't need brakes so when you need them you got them.

 

Something else the old timers that had no jakes taught was it’s not so much keeping it down below the speed limit but keeping it in a safe zone of can the truck come to a complete stop without to many issues on a down grade if crap hits the fan in front of you. Rolling on Jakes in a higher gear may not be the best in some situations.

It took years for the old timers to trust a jake enough to relax a little on grades. Be cautious.

 

That should be every time you fall off a grade!

I live in Colorado. Every trip I see guys using the Jake and brakes to fall off the hill as fast as they can. They have no clue they're screwed if they have to make an emergency stop.

 

Lately.... every single time I come off Floyd Hill, down from the Eisenhower tunnel, or Vail Pass, some fool comes roaring by with a smoke screen behind him. And those aren't even that bad. I take a LOT of state highways and US routes specifically to avoid the Interstates, and places like WV, PA, WA,OR, and CA have some grades that make Vail Pass and Fancy Gap look like a gentle little hill.