gears for hills and general shifting advice

They tell newbies that because you're more likely to miss the shift and then you're in a bad spot. In the real world everyone down shifts as needed going up hills.

 

The adage to take a hill in a gear or two less than you climb it applied to a long time ago when engine power and jake power were much different than today. With jakes today you can effectively take a downgrade a gear or two HIGHER than what you climbed the hill.

Another old wives tale that is still told by DMV manuals and schools is to "never shift on a hill". That's absolute baloney and will get more new truckers in trouble than anything else. You NEED to know how to upshift or downshift going uphill or downhill. If your school is telling you never to shift on a hill, well you have to listen to them as long as it takes to graduate, get your CDL, then forget that crap as soon as possible.

Regarding the idea of "stab" braking going down a hill. The Michigan study for effective braking going downhill has laid that particular method to rest as well. Stab braking is almost maximum braking all at once, to the point of almost locking up your tires. The preferred method of controlling a descent is "snub" braking, or applying up to about 20-25 lbs of brake pressure, applying it gradually to the force you need and holding it for a period of time then gradually releasing it. The rule of thumb is "6 to 1", for every second you are applying the brakes you should have six seconds or more without the brakes. If you're applying brakes too frequently or too long then your brakes can overheat and you should downshift.

Every time down a hill is different, depending on the weight of your load, road conditions, and traffic. If you need to downshift going down a steep grade apply brakes to about 20-25 lbs (snub brake) until your rpm's drop to about 800-1000 rpm, close to the point that the jake isn't working (it normally stops working at 800 rpm). Then make your downshift to about 1200-1400 rpm. REMEMBER THE SPEED WHERE YOU INITIATED THE SHIFT. If you don't hit the gear, then apply brakes to the speed you started the shift and try again. By starting the shift at a low rpm you have a chance to "chase" the rpm's up as you gain speed.

Practice downshifting on downgrades on straightaways where you have lots of room. Make it second nature.

Downshifting on upgrades should be initiated at about 1200 rpm on a steep grade, trying to get the next gear at about 1500-1600 rpm to avoid losing too much momentum. On really steep grades you made need to skip a gear, especially if you are making the dreaded shift from high range to low range.

 

The best way to deal with that is to forget about it. Again, it all depends on the hill, etc.

 

Lets not forget about a head or tail wind along with winter ice and snow. You might have clean roads on the sunny slope and ice on the shaded areas. Slow down is safe everywhere.
The adage of one gear lower meant one gear lower on the same stretch of road. Not opposite side of hill/mountain. In other words. MM10-20 4% upgrade EB. Same Highway MM20-10 4% downgrade WB. Good luck and have a safe ride.

 

If your climbing a hill and losing rpm's fast dont be afraid to drop down 2 full gears.

 

That's just crazy. Hit the bottom close to the speed limit as is safe and downshift your way up the hill until you can maintain your rpms. Pretty much like triple six said. Peak torque is likely 1200 rpm so no point in lugging below that. If the pyrometer gets to 900+ you need more rpms.

More rpms on a downhill grade will let your engine braking work better.

 

Simplest way...if the tach reads 10 to 12k rpms, then go to lower gear when climbing. You know when your in right gear whwn rpms bold steady at 15 to 16k. Goes above 16k then you can go up a gear.

Going down I will usually stay in same gear I climbed up in, if light load. If heavy it is hard to tell each load is different. You have to experiment. On the real steep grades like Monteagle and some on I79 in WV they will have you stop at the top and then tell u what speed to go down in. Example if going south on Monteagle they stop u at top. If 70k lbs do 35 mph, 80k lbs 25 mph. Less than 70, go speed limit of 45, but really it will be what you are most comfortable with.

 

To the OP, here is an article that may be of interest to you. The article is entitiled Give Yourself A Brake. www.overdriveonline.com/smart-driving-2

 

I guess, as mentioned if you dont know the other side of the hill or the GPS is pointing out bottom turns, stops, etc, then you should side on caution and keep it slower than you think is "good enough". We all have to get that experience to make the judgement calls what is right for the truck/load/road/season/grade/upcoming variables. Drive your own trip and the inexperienced drivers best friend is caution. IMHO.

 

on the way back from the dmv my instructor told me "now all the stuff I told you about not shifting while going up and down hills and through intersections, yeah, forget about it"