First trip through mountains

richard5933 · June 28, 2018, 05:03:28 AM

In a couple of weeks we are heading west from the Milwaukee area into Gillette WY. The route doesn't take us through actual "mountains", with flattestroute.com showing the maximum downhill grade at about 4%. However, I want to get some feedback on what to expect from our bus as we wind down the highway, since to me reading that something is a 4% grade doesn't mean much - at least not till I'm driving it and then it's too late to ask.

Our 4108 has a 4-speed and no Jakes. Brakes are in good condition and have been inspected/adjusted a couple of hundred miles ago. I'm aware of the need to downshift prior to starting downhill. I've read all the posts on steady braking vs. stab braking. Not trying to reignite that controversy.

My basic plan is to downshift into 3rd before cresting the peak, then use stab braking to keep the speed down as necessary.

Anyone have advice regarding what gears/speed combination is recommended for various percent grades? Any other tips for safely negotiating downhill grades? Am I worried about nothing with 4% grades?

Bill B /bus · June 28, 2018, 05:55:44 AM

4% grades are common even in the Cheese state. Albeit of fairly short duration. At 6% you know you are climbing. Our first was a 4108 and third gear climbs were frequent. Sometimes down to second gear. And a very few to first gear. For instance Wolf pass in Colorado has a hairpin turn towards the start of the eastbound climb, had to go to first. Then caught a break of slight change in angle and was able to run second gear the rest of the way to the top. Speed in second varied between 18 -25 MPH. The old rule of thumb gear up the hill was gear down the hill.
The biggest problem with Jake brake on a Buffalo is the bulge in the engine door.

Enjoy and don't be afraid of the hills just careful,
Bill

buswarrior · June 28, 2018, 06:28:01 AM

Off the brake far more than on the brake, no matter the hill.

Otherwise, slow down more, while you still can, and grab another gear lower.

The trouble with all the old sayings, you have to have experience to know what they mean...

The coach brakes can only take so much heat, before they won't slow the coach anymore. Once burned, it is permanent. The linings do not grab as well as they should anymore.

Smoke emitting from the wheel wells is definitely a bad thing...

You will be fine on 4% in 3rd, probably no brake required.

If a busnut's speed is more than 20% less than the other traffic, right lane, 4-way flashers on, and carry on. The peeps behind will just have to dealwith it. DO NOT let following traffic be any part of your decision-making as to safe descent speed.

You only get to go downhill too fast once, you may go down too slow indefinitely...

Happy coaching!
Buswarrior

eagle19952 · June 28, 2018, 08:16:44 AM

With your concern, I would, and do go in the lower gears (2nd) on grades.

Once you exceed the buses capability, it's to late.
Yes it's doable.
I have no Jakes and a 740.
Alaska to Prescott and Flagstaff to Sweetgrass plenty.
But,I don't over estimate my bus or my brakes or my experience.
Know all 3 before you decide to start down in 3rd gear.

somewhereinusa · June 28, 2018, 08:36:48 AM

Actually driving with your flashers on is illegal in many states no matter how fast you are going. Not saying not to do it, just pointing it out.

Just the first sight I went to. I knew about CA, not the rest.
https://driversprep.com/when-should-you-use-emergency-flashers/

richard5933 · June 28, 2018, 08:50:29 AM

Quote from: somewhereinusa on June 28, 2018, 08:36:48 AM
Actually driving with your flashers on is illegal in many states no matter how fast you are going. Not saying not to do it, just pointing it out.

Just the first sight I went to. I knew about CA, not the rest.
https://driversprep.com/when-should-you-use-emergency-flashers/

Interesting, but obviously confusing in the way this plays out in real life. Seems like even in states that generally don't allow driving with 4-way flashers active many still allow it if alerting to a dangerous situation. Wouldn't driving slower than traffic up/down a steep grade be the definition of just that - a dangerous situation.

In Wisconsin (where according to that site the practice is legal) semi drivers will turn on their 4-way flashers whenever they encounter sudden slow downs or traffic obstructions. Seems like they are trying to let drivers behind them know that something is going on in front of them, which is a good idea since drivers behind them can't see around the semi.

eagle19952 - What's the upper speed you can maintain with your 740 in 2nd gear? In our 4108 with the 4-speed, 2nd maxes out at about 30 mph.

lostagain · June 28, 2018, 10:21:16 AM

In all states and provinces, in actual real life, 4 ways are used by trucks and buses going less than 40 mph, to warn others of sudden slow downs and traffic hazard, in bad weather, etc.

JC

lostagain · June 28, 2018, 10:21:40 AM

In all states and provinces, in actual real life, 4 ways are used by trucks and buses going less than 40 mph, to warn others of sudden slow downs and traffic hazard, in bad weather, etc.

JC

edvanland · June 28, 2018, 10:29:42 AM

All good advise. I live in northern Arizona 6% to 7% grades are the norm. Stay in right lane, gear down before you start and enjoy the scenery and don't worry about what is behind you.

Branderson · June 28, 2018, 12:27:31 PM

I'm extremely nervous to go into any type of mountains. Isn't it true that there is a way to break also? I was told when braking to brake and let up a little and brake again so it's not a constant pressure.

buswarrior · June 28, 2018, 12:51:36 PM

The brake linings will not withstand constant contact on downhill running at "normal" speeds.

There is too much energy to convert into heat.

The driver is a heat manager on downhill sections.

The coach has to be controlled by a combination of slower speed, choice of lower gears, and occasional use of the brakes.

As a option, an engine brake/Jacobs engine brake/exhaust brake/transmission retarder is a feature which increases the driveline's ability to make some slowing force.

eagle19952 · June 28, 2018, 02:58:09 PM

Quote from: richard5933 on June 28, 2018, 08:50:29 AM

eagle19952 - What's the upper speed you can maintain with your 740 in 2nd gear? In our 4108 with the 4-speed, 2nd maxes out at about 30 mph.

Depends. Uphill ? I've seen 22mph. this would be the west side of Yosemite (Tioga Pass).
My post refers to down hill.
With the Allison and no Jakes. One is best to try to hold the same, 20 mph.
My point, if one does not know the lay of the land...
Like warrior said, there is no worse experience than your brakes getting worse than they were 1/4 mile ago...

windtrader · June 29, 2018, 10:24:17 PM

Personal experience with the MC8 8v71n/HT340, 32k pounds at the scales, got down the west slope of the Sierras, some sections at 6%, with Jakes on with no issues. Occasional braking at the end of the steep sections leading into curving sections. Transmission gears were also used with the Jakes to maintain a comfortable brake off speed.

chessie4905 · June 30, 2018, 03:39:49 AM

When using engine to assist holding coach back,, watch rpm's that they don't exceed governed speed.

richard5933 · June 30, 2018, 03:43:21 AM

Quote from: chessie4905 on June 30, 2018, 03:39:49 AM
When using engine to assist holding coach back,, watch rpm's that they don't exceed governed speed.

No tach. Best I can do is keep an eye on the speedometer. I'm good to about 50 in 3rd.