Community Forums

frederick w · 12-03-2010, 03:38 PM

On a 10 to 15yr. old class A for example, is the stopping
power on a diesel better than a gas rig. Example decending
steep grades. I realalize it may depend on what kind of
chassis is under the coach.

Sorry if this question is too general.

I would go supper
slow in either case and work the gears.

Some what concerned as my 2000 Flair is not a high level MH.
It does have abs 4 way disk brakes ( work horse chasis) I
haven't driven other rigs so I don't know what's good or bad.
Of course if the stupid auto park engages, I'll have extra
stopping power.

Fred from Pasco, Wa.

travelgirl · 12-03-2010, 04:02 PM

I settle for no less then air brakes if i have my choice...

RickO · 12-03-2010, 04:09 PM

Hi Fred. It is a general question but that's ok so long as you're allright with general answers.

I purchased my first coach a few years ago and the main fear I brought into the process was that of stopping that big thing. Nightmares played in my head about brake fade turning to total loss of braking and me looking for one of those runaway truck ramps.

I ended up buying a diesel in part because of that. Now with 34,000 miles under my belt I still don't have any experience with a gasser but I feel very comfortable being able to control my coach on downgrades of all types and lengths. A big cause of that is the two stage engine brake. I flip a switch and it's like throwing out a big sail behind me. If that's not enough, I flip the switch the other way and it's like throwing out an anchor. For me it's a great sense of security.

It's my understanding that downshifting in a gasser provides substantial braking power as well but I don't have the experience to compare them.

Good luck

Rick

mikron · 12-03-2010, 04:39 PM

I would think the weight differance between gas and diesel would make them equal. The 4 class A MHs I have owned have been gas. The one we own now is a Ford F53 GW 22,000 lbs. Drop to 3rd then 2nd and you have very good slow down. I don't think a 40,000 lb MH, gas would stop shifting down.

RickO · 12-03-2010, 04:52 PM

Quote:

Originally Posted by mikron

I don't think a 40,000 lb MH, gas would stop shifting down.

Hi Mike.... can you explain?

Thanks,

Rick

RJay · 12-03-2010, 05:32 PM

A gasser usually has a three speed transmission with overdrive and hydraulic breaks. A diesel has a six speed transmission, two stage exhaust break and air breaks so the the strategy of how you approach the hill is somewhat different. The grade, length of the grade and traffic all play a part in the strategy.

My previous motorhome was a 2000 Itasca Suncruiser 37G, V10. When I saw a road sign indicating a down hill grade I would shift out of overdrive and reduce my speed until between 40 and 45 mph. Road grade signs don't always say how long the grade is and never about the traffic condition on the other side. I would usually coast over the hill until I could survey the grade length and traffic. Usually I would coast down, without gas, until the speed got between 55 and 60 at which point I would apply hard constant breaking until my speed was back to 40 to 45. If I gather speed too fast I would shift to a lower gear. In my opinion, the important thing to remember is not to feather the breaks down the hill, only a very hard constant application of the breaks to reduce speed to 40 to 45. If it's raining lower the speeds by 10 mph. The steeper the hill and longer the grade, the lower the gear and the slower the speed.

I've been all over the US including Alaska and I've never had a problem with hills using this strategy so don't let hills deter you from buying a gasser. But now that I have a diesel, my vote is easy, a diesel no question.

Mike Canter · 12-03-2010, 05:34 PM

My Sig has monster air powered disk brakes on the steer and drive axles and monster shoes brakes on the tag axle plus the two stage Jake brake. The Jake will automatically start downshifting that transmission for you. I also have a very large footprint on all eight tires and have ABS on all axles. I have made one close to a panic stop and it is scary how fast it will bring a 48,000 lb MH to a stop. The tires were chirpping as the ABS was doing its work. My big problem is not having everything in the MH come flying forward or having the guy behind me hitting the toad.

I have no problems going down steep grades. I recently went over the pass on I-5 crossing the border between Calif and Oregon. That is 6% grade for six miles and I have done the Grapevine in Southern Calif. Never had to use the service brakes with the Jake brake and keeping the transmission downshifted.

I had a car drift out from a stop sign on a back road in Texas. He was either picking something up from the floor or was texting and took his foot of the brake pedal and ceawled forward into my path. I was doing 65 in a 70 and there was no way even with a parachute or an anchor I was going to stop. I did an evasive manuever and took the wide Texas shoulder while blasting him with the air horns. He woke up and turned onto the lane going the same direction as me and I passed him on the shoulder. I was amazed as to how the MH handled that manuever because one would never pactice anything that severe. My wife didn't say anything for about and hour. Then we relived it for several hours. Like I said there was no way I could have used the brakes and stopped before I would have t-boned him.

RickO · 12-03-2010, 05:53 PM

Quote:

Originally Posted by Mike Canter

My wife didn't say anything for about and hour. .

Mine would have been asking..... "what's that nasty smell?"

Good job Mike. I'm afraid I would have T Boned me one Texan.

Rick

SteveLevin · 12-03-2010, 06:06 PM

While I want the air brakes and exhaust brake of a diesel, the reality is, I've never had brake issues in my 17,000lb 1991 F53, and I have just 16" wheels (so the brakes aren't that huge). I do downshift from overdrive into drive, though. Coming down the Grapevine, for example, in drive, I can hold 55mph, which translates into something like 2800rpm on the engine (so nowhere near redline).

the worst time I've had (and I still didn't even get a soft pedal) was coming down from Yosemite on Hwy 120; there, the speed one could drive was about 45mph -- which is too slow for engine braking in Drive to hold without using the service brakes (and 35mph in 2nd is as hard as I push 2nd, and it would have been decelerating rather than steady state). If I had a 5 or 6 speed transmission (so smaller gaps between the gears) even that wouldn't have been the issue.

What gets to me after a while is the noise; the dull roar wears you out over a while. That's one of the reasons I want my next coach to have an engine in the back. But from a safety standpoint I've had no issues, and I've tackled a lot of mountains and have never had to pound the service brakes.

Steve

Barbaraok · 12-03-2010, 06:34 PM

Quote:

Originally Posted by RJay

A gasser usually has a three speed transmission with overdrive and hydraulic breaks. A diesel has a six speed transmission, two stage exhaust break and air breaks so the the strategy of how you approach the hill is somewhat different. The grade, length of the grade and traffic all play a part in the strategy.

We have a diesel with hydraulic brakes. Handles like a dream.

I believe what the OP was asking about was coming down a steep grade, not coming to a complete stop. And for ease of doing that nothing comes close to an exhaust brake.

Barb

frederick w · 12-03-2010, 06:50 PM

Thanks guys for the info. I may look for an older used diesel in the future. The brakes on my 2000 Flair need alot of foot press to stop. I found out on the forums that this is par for the P-32 chassis.
I met a RV owner that had a 2008 that took alot to stop. It was a Hurricane with a Ford V-10.
One would think that the newer MH would be better
as far as stopping. So I guess I'm not alone.

Fred from Pasco, Wa.

mikron · 12-03-2010, 06:52 PM

Quote:

Originally Posted by RickO

Hi Mike.... can you explain?

Thanks,

Rick

Gas stoping for 22,000 to 26,000 lbs rig over diesel atr 40,000+ lbs, like apples to oranges for compairing brakes I think. 40,000 lbs regular brakes, I don't think would work.

Vegasdan · 12-03-2010, 09:21 PM

My rig weighs 25K plus towing my 3500LB Wrangler. This year I've driven on many roads with 6-7% grades. I've followed gas rigs down many and I always notice the brake lights on most of the way down. My jake brake allows me to just tap the service air brakes only when I need to bring the speed down for control. My brakes were checked last year and they still had over 60% linings with 77K miles on the clock.

Midniteoyl · 12-03-2010, 10:18 PM

Quote:

Originally Posted by frederick w

Thanks guys for the info. I may look for an older used diesel in the future. The brakes on my 2000 Flair need alot of foot press to stop. I found out on the forums that this is par for the P-32 chassis.
I met a RV owner that had a 2008 that took alot to stop. It was a Hurricane with a Ford V-10.
One would think that the newer MH would be better
as far as stopping. So I guess I'm not alone.

Fred from Pasco, Wa.

You might wanna check out those brake lines and fluid. 2 years is the 'change the fluid' period for brakes. When you do, move up to a high spec DOT4+ fluid. Unless you have DOT5 already.