[Tom]

Come on Jon what would you do??

[George]

Art, are you worried, you don’t have enough power to climb the grade?

[Jon]

Once I start I don’t want to stop, I hope it has the power and torque to climb out, like I said drive or 1st gear, I want to get it on the 1st try. Jon and Tom have been around Prevost buses for a long time, what would they do?

[Jon]

Art, sorry for the slow response because I haven’t had time to even get on the computer recently.

First, I can tell you for certain I have never been on a hill as steep as my driveway. Those that have can post their opinions about if it qualifies as steep but let me assure you that several bus owners have lost traction part way up and had to go back down to get a new start.

The way I approached hills was to “drive it like I stole it” but that applies to roads where you were not controlled by sharp curves or other impediments to speed. If I am climbing a hill from a stop or a near stop, forward or reverse, I use “D” or “R” and apply gas as needed. If the transmission is at a shift point such as when going forward you have the option of holding it in that gear by punching the down arrows in advance or by putting it in performance mode which lets it hang in a gear longer.

If the transmission upshifts and then that gear cannot maintain speed that is when based on experience you know to limit how high the gear should be. On roads I never travelled I would not know what gear will maintain speed so performance mode will allow it to downshift quickly to at least hold speed.

In reverse or 1st gear nothing will stop the bus except loss of traction but if the hill is so long you do not want to stay in first start out with the use of the down arrow to limit it to 2nd or third, both of which are capable of climbing steep roads.

On highways or at least decent roads I have a sense of what gear I will have to be in and typically I put it in performance mode, drop to fifth, floor it and carry extra speed into the hill. Then I let the transmission drop into lower gears as necessary. I have had hills steep enough to get the transmission to drop into third, and with performance mode selected it stays there until it hits 2100 RPM and upshifts. If it drops into 3rd again and starts hunting, I know I am 5th, so I will hit the down arrow twice to keep it in 3rd and just either keep my foot on the floor or let the cruise control run it at that point. You get more HP available in cruise control than you do with it off.

If you know what speed you are at in 2100 RPM in each gear and you know what speed you want to make the hill at you can always use the arrows to select the lowest gear that will give you that speed.

I have never picked the hill climbing gear in advance because the bus in performance mode kind of does its thing well enough I can allow it to control the hill climbing speed. I do have a hill near my house that does not allow me to do a running start and the bus is usually in first when I hit it at the bottom, but I just let it do its own thing. It is a short hill so I am OK letting it decide when to upshift, and it still hunts when it gets into third, but it usually drops into 2nd, then upshifts into third once or twice before It levels out. It is no more than 1/4 mile so I am lazy and let it do what it wants.

If traction is a concern however and you have a toad on back, that is a whole different story. I would never start up a hill with the toad on back if I thought I had the chance to lose traction. I am not saying how I climb hills is right, but the methods I use have worked OK so I stick with them.

[Art]

Just drive it like you stole it! Wide open throttle up the hill……

[Jon]

1st gear or just let drive do it’s thing

[Dick]

Thanks guys I tend to overthink things, Jon the drive way going into the park is nice smooth asphalt a little bit of a turn about 1/8 mile long not much of a run 50 feet, I have never used eco mode or performance mode, it is steep enough where 2 gear is not a option

[joel]

FWIW I have never encountered a hill I couldn’t take in 3rd, but I also know if it is steep enough or has a curve that lowers the speed it would not necessarily allow 3rd. Going up a hill that is steep traction on a hard surface is not an issue, but the same hill going backwards can cause the loss of traction as weight shifts forward so the driving technique may come into play. I will never suggest to anyone backing up my driveway to lift their foot from the go pedal because it is likely they will lose traction. Each circumstance may be different so decisions about technique are going to vary when needed.

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1999 XLV X-6872,  liberty #440

[Dick]

So I maybe have a 50 foot run at the drive way out it will shift 1st to 2nd and maybe 3rd gear?? To me 1/8 of a mile steep road going out nice asphalt, I was going to put gear into 1st and cruse up keep rpm’s up to the top ,then hock up toad. Jon you said I will not run out of power? I was going to warm up bus drive through park to get trans fluid moving , then hit the hill,?

[Tom]

Let me clarify something I said that maybe wasn’t said right.

On public roads and over a 32 year time frame the lowest gear my bus downshifted into has been 3rd. But that was based on starting uphill at anything but a dead stop. Going the other way up through the gears even the short steep hill I described earlier (with a bad curve) I can get into 3rd, but the curve makes me lift the throttle enough to lose just enough speed so it will down shift, but it will get back into 3rd again, but again if I lift my foot it is back into second.

I think as you describe the hill, leave the toad unhitched just in case you have to back up, put it in performance mode, and just floor it. Let the transmission decide where it wants to be. If it hunts for a gear, at that point you know what gear it is capable of maintaining, and on subsequent runs start out with that gear selected as your top gear. I’m trying to remember gear speeds and I think 1st is 15 or thereabouts, I am not sure of 2nd, 3rd seems to be 35, forth is 55, and 5th and sixth exceed my 62 MPH. I would be confident in saying if you do not want to push your speed too much, then select 2nd and floor it. I seriously doubt you have a hill that is so steep you have to be in first.

Do not be afraid of keeping your foot to the floor and holding the RPMs at 2100. DDEC will not allow you to hurt the bus. It is when descending a grade and start exceeding 2100 because the weight of the bus is pushing the speeds up that you can easily exceed 2100 and that is a bad thing.

[Randy]

I guess I’m running against the grain here, but on short steep grades (16% or so) I lock in 1 to prevent unnecessary wear on shift clutches. Of course, I’m also usually pulling a 15-20,000# trailer.

[Dick]

Like I said I just need to get out of park on a 1/8 mile long driveway nice smooth asphalt no room for a run at it 1st gear floor it.

[Jon]

Let us know how it goes. I wonder how steep an incline our busses can climb up without a running start?

[Dana]

With the torque a Detroit Diesel puts out … probably steeper than you (or most of us) want to tackle!

[David]

All my 3 buses handle my 30 degree driveway and have for 32 years. Anything less than 30 degrees is not steep.

But I am glad I am not backing up with 20,000# of trailer.