Skip to main content ↑ ↓
Topic: Time to go over going down steep grades,  (Read 1920 times) previous topic - next topic

Time to go over going down steep grades,

Brake failure behind RV crash | Local | jhnewsandguide.com

First I pray for the family and the driver. I bet the driver is now wishing that they would have known how to go down long down grades in a motorhome.

Not sure if the coach had a retard, jake brake, or engine brake or even if the driver knew the coach had one or how to use it.

I have read many threads on here that go over how to safely going down long grades and will find one to add here.

Re: Time to go over going down steep grades,

Reply #1 –
What sad news... you don't know what you don't know. That is not a pass to mess around with unless you're an experienced driver and there's a fairly easy bypass to get around it. And it's extremely well marked.

Now that I don't have any, I have found auxiliary braking systems like Jake brakes/retarders, etc.. are unnecessary if you know what you're doing but REALLY nice to have none the less. The U320 was a mindless experience going down steep grades compared to the GV. With just a 4 speed transmission and drum brakes I have to put a lot more thought into my driving in the mountains but have never felt unsafe.

Re: Time to go over going down steep grades,

Reply #2 –
I drove our ex-Greyhound for many years with only drum brakes. I also never felt unsafe but it did require a bit more planning than the U300. The secondary roads may be quite a bit steeper than the interstates and on all grades, I check the air pressure at the top and select the right gear ahead of time. I also never let traffic behind dictate how fast I head down.

Most of the time, the Jake takes care of keeping the speed down and I keep it switched on all the time. But descending into Jackson, WY was steeper and longer than I thought it was going to be so I pulled off a couple of times to let traffic by and to cool the service brakes. Even then, the brakes smelled at the bottom.  As I remember, there were two roads down. I stupidly took the road that said "not recommended for RVs" because it was shorter.

Pierce

Re: Time to go over going down steep grades,

Reply #3 –
Having driven in mountains all my life my rule is brakes are for stopping not for maintaining speed
down hills.

Re: Time to go over going down steep grades,

Reply #4 –
10% grade- not going that way.

Re: Time to go over going down steep grades,

Reply #5 –
Big difference to me going down 10% grades in the Rockies was to follow posted advice here to downshift the transmission to maintain a max rpm on the engine at the top of the downgrade. Better engine braking, better trans and retarder cooling noticeably added to feeling more in control.

A few years ago I found an eBay auction on Meritor disk brake rotors.  Not steel. Nodular iron. $$$+ noticable stronger brake action. Front only so far. Much higher frictional coefficient it seems. I have no way to know if I have extended the brakes ability to absorb heat but the cold blooded feeling my brakes always had was almost eliminated.

While driving in surface streets I used to regularly warm up the brakes versus rely on the retarder as much.

With the nodular iron front rotors I no longer do that. The  much stronger braking action cold eliminated that action.

Lots of money for the rotors. But if you had the budget available you would really like the much stronger braking feel and reserve that may be available.

OREDS need to be used hard to engage the front drums then coast

Re: Time to go over going down steep grades,

Reply #6 –
Years ago going up that thing in our ford diesel towing a 24' TT I remember the DW asking me if we had "another" gear to drop down into. Nope... already in first gear.
  I've not gone down the thing yet but after going up it I'm thinking in 2nd gear maybe 3rd w/ the retarder.
  Cause, I'm in no hurry.

Re: Time to go over going down steep grades,

Reply #7 –
I crossed Teton Pass from west to east this past Sunday 9/1.....3rd gear with a good deal of combination retarder and brake use will suffice for a "light, non slide U270". I also pulled over a couple of times to let traffic pass, neither were really hot but this let the transmission and brakes cool a bit.

Teton Pass is not for the faint of heart in either direction but common sense and proper use of brakes/tranny/retarder will get you down safely.....oh did I mention, don't get in any hurry.....

Some dude was parked directly in the first runaway truck ramp, I mean he didn't just pull over blocking the ramp, he backed into it several feet!! The second runaway ramp is a cable type....and yep, 60,000lb weight limit was well advertised, no way could anyone not be aware of that.

Re: Time to go over going down steep grades,

Reply #8 –
This week we went down west rabbitears pass into steamboat springs and back up today.  The old hill climbing rule came into play, go downhill in a lower gear than you went up in.

Re: Time to go over going down steep grades,

Reply #9 –
I haven't had to do any really big grades in the GV yet, but the few I have I've used the trans retarder and brakes without issue. I was taught when getting my CDL, that you apply the brakes firmly and drop your speed 10-20 mph and then let the retarder/engine braking work until the speed climbs back up, Then apply the brakes again. This gives the brakes time to cool in between applications. That's if your retarder/engine brake isn't enough to keep your speed where you want it. Riding the brakes for a long time is bad, just builds up heat, but on and off applications give them time to cool off.

Re: Time to go over going down steep grades,

Reply #10 –
Quote from: kgrover –
I haven't had to do any really big grades in the GV yet, but the few I have I've used the trans retarder and brakes without issue. I was taught when getting my CDL, that you apply the brakes firmly and drop your speed 10-20 mph and then let the retarder/engine braking work until the speed climbs back up, Then apply the brakes again. This gives the brakes time to cool in between applications. That's if your retarder/engine brake isn't enough to keep your speed where you want it. Riding the brakes for a long time is bad, just builds up heat, but on and off applications give them time to cool off.
We had a couple of fire trucks that were automatic and had retarders. On extended grades, the retarder may overheat and the warning light come on. This is because the ATF is overheating and continued use may cook some seals. It's the secondary roads that can sneak up on you length wise. Seeing the light come on when you are in a hurry with 1000 gallons of water right behind you can cause a couple of anxious moments.

If our Jake can't keep the speed reasonable, then I do exactly as you describe in your first sentence.

Pierce

Re: Time to go over going down steep grades,

Reply #11 –
So I recently had some experience navigating steep long grades on i70 in Colorado summiting Veil pass and the Eisenhower tunnel and I got to wondering, if you gear down and your running near max rpm's is there a risk that gravity will cause you to gain speed and risk pushing the engine over it's red line?  I know the obvious answer is to use the brakes to prevent that but there can be a lot going on fighting for your attention, especially on a 3 lane interstate with heavy traffic and you can easily lose track of your speed for a few moments.  I tow a trailer with a Jeep on it and I scaled in at 45k lbs. combined which can pick up speed in a hurry going down hill.

Re: Time to go over going down steep grades,

Reply #12 –
The transmission. May force an upshift to the next gear to save the engine,  but I have no idea if the allison is programmed for that or not.

Re: Time to go over going down steep grades,

Reply #13 –
Find a gear that will hold your speed with your retarder on second notch and RPM between
1800 2000 go slow. I drove the Gaspe Peninsula which had a lot of 15percent grades and
finished with a 17 percent grade. I had a Monaco Dynasty and I would put it in 1st gear and
with the exhaust brakes that would hold the coach without using the brakes. Nice and safe
and relaxing.

Re: Time to go over going down steep grades,

Reply #14 –
On the other side of this conversation when i was testing my coach i went down the grapevine in Southern California from Lebec to grapevine and the normal 55 mph speed limit at 35,000 pound combined. Added the amount of retarder needed to maintain that speed.  3 then 4th position and 5th and watched the trans temp slowly rise.  At the very bottom of the grade the  red warning light came on. Trans temp 250 or so.  Turned off retarder as the highway was barely down hill now.  Within 2 miles the red light went off.  I had the wheel brakes as a reserve.  Wanted to see how and if the system was working.  I have had the trans get to 238 or so several times with downshifting and using lower gearing and speeds which i then use the wheeel brakes.  Noticeably stronger brakes with the addition of grey iron front rotors   

Re: Time to go over going down steep grades,

Reply #15 –
Quote from: Geodmann –
So I recently had some experience navigating steep long grades on i70 in Colorado summiting Veil pass and the Eisenhower tunnel and I got to wondering, if you gear down and your running near max rpm's is there a risk that gravity will cause you to gain speed and risk pushing the engine over it's red line?  I know the obvious answer is to use the brakes to prevent that but there can be a lot going on fighting for your attention, especially on a 3 lane interstate with heavy traffic and you can easily lose track of your speed for a few moments.  I tow a trailer with a Jeep on it and I scaled in at 45k lbs. combined which can pick up speed in a hurry going down hill.
Pick a lower gear and get in the slow lane is the best way. Then you can relax all the way down.

Pierce

Re: Time to go over going down steep grades,

Reply #16 –
Goodman - Here's a short previous thread that may tell you what happens when the engine hits redline.

Check engine light - high fuel pressure

I have not tried to duplicate the experience and it has not happened again.

Rich

Re: Time to go over going down steep grades,

Reply #17 –
Quote from: Olde English –
This week we went down west rabbitears pass into steamboat springs and back up today.  The old hill climbing rule came into play, go downhill in a lower gear than you went up in.

YEP!!

Re: Time to go over going down steep grades,

Reply #18 –
Reading these posts makes me long for the days I had a Jake Brake, yes it was noisy but it worked so much better than the retarders fitted to our coaches. No over heating no matter how long the downhill drive. With the Jake I only used the brakes as my final stop at a stop sign, the Jake did all the major work to reduce the speed and momentum.
The retarder is a nice extra, but it's no Jake!

Re: Time to go over going down steep grades,

Reply #19 –
I have both and in mountain driving I love the Jake and in town I use the retarder. If I find I'm
in too high a gear with Jake I will use the retarder to get me into a lower gear. Sometimes I don't
want shift down and the Jake won't quite hold the speed I will use the first notch with the retarder.