gears for hills and general shifting advice

Oh boy! So you would slow down from say 55 and get into 5th gear at the bottom of the hill...yikes

 

Forget about the one gear lower theory. That only works if both sides of the hill are exactly the same grade and distance. That's hardly ever the case.

How do I know what gear to climb the hill in

Youre on flat ground in top gear. Accelerate as much as you can safely and hit the hill carrying as much momentum as you can. The weight will start dragging you down, and you will have to downshift. When you get to the point to where the gear will maintain around 1300 rpms, that's the gear you need to be in. You don't want to lug a motor at 1000 rpms uphill, because the exhaust gas temps will probably get too hot and burn up the motor...especially if you have big power.

How do I know which gear to go downhill in?

Roadsigns will give you a clue. Sign says ATTN TRUCKERS: STEEP GRADE AHEAD. 6% GRADE NEXT 4 MILES. TRUCK SPEED LIMIT 45mph.

Okay, you dont drop a gear and plan to run 45 mph on unfamiliar road...especially if you are loaded heavy. Drop your speed on flat ground, find the gear you can run 35 mph at 1500 rpm, get your speed down to 30 mph, full jake and try it. It should be enough to hold you. If it's not, the rpms will build slowly and the jake will get louder and stronger. You get near 40 mph, stab the brakes and release them. Stabbing the brakes is not riding the brakes all the way down hill. STAB is not a soft touch either.

 

"One gear lower going down than the one you used going up" is an old wive's tale. Say you went east up Cabbage with 44K in the box then went west down Cabbage with 8K in the box. Same gear? IT DEPENDS ON THE HILL, THE WEIGHT OF YOUR LOAD, THE TRUCK, THE GEARING, THE ENGINE, THE POSTED TRUCK SPEEDS ON A DOWNGRADE, ETC. ETC. Sometimes, the downgrade isn't the same grade as the upgrade (hills have two sides). There's no rule of thumb, but not to worry. As you gain experience, you'll learn to adjust to each hill and each situation. Going up, you just gear down and down until you've got the gear you need to keep moving without stalling or winding the engine off the motor mounts. That's how I did it. If you're going slow (slower than some people would like you to go and they have to tell you about it on the CB) in the climbing lane, well, that's what climbing lanes are for. If there's no climbing lane you do the best you can. If someone thinks you're going too slow downhill that's their problem--they can only drive one truck at a time and it shouldn't be yours.

 

I wonder how many rpms a tach reads when doing 50+mph in 4th?

 

Learning how to downshift will answer all your questions....if that makes any sense.

 

In 4th gear your max speed would be 10 mph. You must have made a typo when you said 50+ mph.

As far as uphill gear goes, the terrain will change and you should upshift when you reach your top engine rpm. And you should downshift when your rpms drop too much.