dualie or not - Page 4 - Montana Owners Club

texdeano · 03-02-2007, 04:51 AM

I'm with you bsmeaton!

dsprik · 03-02-2007, 06:05 AM

I don't like waiting for road service to find me after their boss gave them the wrong directions (I'm probably the only one...) I will go with 4x4 SRW.

sreigle · 03-03-2007, 12:04 PM

I have put a lot of miles on single rear wheel trucks, towing Montanas and other brand fifthwheels. I see a couple of reasons where going with a dualie is necessary. One is if hauling a livestock trailer where some heavy animals move around in the trailer. Another is when hauling a slidein camper. At least one of the larger ones. I had a smaller one on a SRW truck with no problem at all. The other reason I can think of for a dualie is if a person just wants one, for whatever reason.

As for stability, I never questioned whether six wheels on the ground would be more stable than four. However, that's not much different than saying a Ferrari will go faster than my Ford SuperDuty. The question is one of need. Do I need to go faster than my Ford will go? No. Is there a stability problem when towing a Montana with a SRW truck? No. Therefore, when considering towing a Montana, in my opinion a dualie is a solution to a problem that does not exist. If you want a dualie or have one of the other needs I listed, go for it. It sure won't hurt. But it's not necessary for towing a Montana. Over 100k miles towing FW's with a SRW inlcluding probably 75k towing Montanas and I've never felt a stability problem.

For towing Montanas, my opinion is if you want a dualie, get it. If you don't, then don't.

DarMar · 03-03-2007, 12:04 PM

For those members who are looking to glean information from this thread about dually or not I feel we must settle the positives of a dually once and for all, it seems the negatives are already agreed upon in this thread.

#1 As Cat320 stated "To say a dually is not any more stable than a single rear vehicle is totally absurd" I must absolutely AGREE with!!! Dual wheel vehicles have a wider wheelbase due to the extra two wheels mounted outside the regular wheels. Like it or not a wider wheelbase adds stability and you cannot argue against that.

#2 In my 24 years of owning a furniture store and using dually delivery vehicles I never had BOTH inside & ouside duals go flat at the same time. Yes indeed it is imperative to check the tire pressure of the inside dual as often as you would any other tire.

As I stated before we bought our dually for extra payload, added stability and the added piece of mind having an extra set of tires on the rear during a blowout.

Yes, there are now two extra tires to buy when ours wear out.
Yes, we don't get as good of mileage with the extra two.
Yes, the dually hangs up in soft substances such as mud & snow, so I would recommend a 4 x 4.
No, it is not a lot different to drive around town and park than any other heavy duty truck, remember if your towing mirrors will go through a space the dual wheels are no wider and most of us have those large towing mirrors anyway.

SKOOBDO · 03-03-2007, 12:23 PM

Quote:

quote:Originally posted by DarMar

For those members who are looking to glean information from this thread about dually or not I feel we must settle the positives of a dually once and for all, it seems the negatives are already agreed upon in this thread.

#1 As Cat320 stated "To say a dually is not any more stable than a single rear vehicle is totally absurd" I must absolutely AGREE with!!! Dual wheel vehicles have a wider wheelbase due to the extra two wheels mounted outside the regular wheels. Like it or not a wider wheelbase adds stability and you cannot argue against that.

#2 In my 24 years of owning a furniture store and using dually delivery vehicles I never had BOTH inside & ouside duals go flat at the same time. Yes indeed it is imperative to check the tire pressure of the inside dual as often as you would any other tire.

As I stated before we bought our dually for extra payload, added stability and the added piece of mind having an extra set of tires on the rear during a blowout.

Yes, there are now two extra tires to buy when ours wear out.
Yes, we don't get as good of mileage with the extra two.
Yes, the dually hangs up in soft substances such as mud & snow, so I would recommend a 4 x 4.
No, it is not a lot different to drive around town and park than any other heavy duty truck, remember if your towing mirrors will go through a space the dual wheels are no wider and most of us have those large towing mirrors anyway.

Well put...Can I hear an "Amen"! Thanks DarMar.

Mac · 03-03-2007, 12:58 PM

I have owned a Class C and have had both duals go flat, or blowout at the same time, not once, but four different times. I have never owned a dually pickup and don't know if it translates into anything similar but it can and does happen.

mac

Dave e Victoria · 03-03-2007, 03:53 PM

The emphatic responses this topic excited from Cat320, DarMar and Skoobdo got me to thinking (again). The concept of stability is well defined and should be describable mathematically. Turns out after a little musing the problem is fairly simple. I submit that there are two components of stability for this case. The first is the ability to stay put from a significant side load such as a strong wind that caused the vehicle to slide sideways across the road. The second would be a tipping force. That would be a force that pushed sideways and tried to tip the vehicle over its outside tire. This assumes the tire has enough traction not to slide. In this case the classic definition of stability is the tendency for the vehicle to right itself after being disturbed.

In the first case, the sliding action is prevented by the friction of the tires against the road surface. Any freshman physics student can tell us friction is downward force times the coefficient of friction. In our case the downward force is the weight of the truck and trailer over the rear axle. This is substantially constant between SWR and DRW except for a slight increase from the extra wheels and bigger fenders of the DRW. Adding wheels or surface area does nothing to change coefficient of friction. So in both cases the sliding or skidding stability is essentially equal.

Now, for tipping stability. The wider wheel stance does appear to add stability. The question is how much. Turns out a bit of geometry and kinematics reveals that a tipping force is divided by the value of the tangent of the angle at the outermost tipping point of the truck as related to the height of the center of gravity of the vehicle. The lower the center of gravity the more stable in any case.

I worked an example. Lets assume the center of gravity of our load is even with the top of the truck bed or about 48 inches above the roadbed. Then assume the distance to the center of the rear tire on a srw is 36 inches from the center of the bed. The stability effect is 36/48 or 0.75. For the DRW vehicle the center of the outer tire is an additional 8 inches outboard so the effect is improved to about 44/48 or.91. So, for tipping stability the improvement is ((.91-.75)/.75)=21%.

Well, there are some real numbers put to the situation. And here is the crux of the dilema. The improvement is at least noticeable but quite easily overcome by driving technique and actual load conditions such as lowering the center of gravity of the load.

Now that was fun and I discovered why the Cambridge always seemed more stable than our 3295 Montana. Simply, better friction due to bigger load and somewhat lower COG.

Dave

dsprik · 03-03-2007, 04:56 PM

I was just going to say that, Dave...

I do like your numbers and I agree with your final summary...

richfaa · 03-03-2007, 06:00 PM

What Dave said...what he said....

keham · 03-03-2007, 06:42 PM

Well I had both and I don't like the dually for one reason. I could not zip thru the auto car washes. when I am fully loaded I have about 140 lbs to spare on my gross on truck and am under my tire weights. The only CC type srw I believe should be the ford 350 because of its 11200 gvwr to insure to have a good margin. But because of my bad experience with Ford I got what I have and really have to watch my weights. But not all Montana's have the same pin weights because if you look at all the different models you will see the distance of the pin to center of axles are all different between the models. (believe me I measured them all and with my portable 5000 lbs scale I weight them all at the dealer empty. I bought the size unit I wanted that had the lowest empty weight on the pin. Otherwise I would have had the 3400 instead of the 3475. vehicle weight ratings are there because the Mg rates it for weight (liability and regs is why, Liability being the main reason for pick ups.) Get the truck that will do the job you want it too and what you feel safe with; but a half ton is not a good choice but have seen many pulling big 5th wheels.

ken

Cat320 · 03-04-2007, 03:40 AM

Quote:

quote:Originally posted by Wrenchtraveller

---disparaging remarks deleted---hotr

Why??

As SGT Joe Friday said...it contained "just the facts ma'am," was not hostile and did not get personal.

richfaa · 03-04-2007, 04:16 AM

TAKE IT EASY GUYS..There are "some" valid points on both sides of the discussion.All one can do is to present the valid facts for consideration. Once the individual has read and understood the facts they have a decision to make..based on fact and data not what someone thinks or says is right or wrong.There are many deciding factors in the TV we purchase. How we use it and most importantly..what we can afford.There are 3/4 ton trucks that can pull a Montana and stay within all specs.. there are 1 ton SWD that can pull a Montana and stay within all spec's. There are many of us, like to admit it or not, are pulling over spec's. I have seen 1 ton duallys pulling over spec's.All I can suggest is that we not attempt to force the other guy into doing what we think is right or wrong. Present the facts..make sure they are the facts and let the other guy make the decision. Ole Rich covers all the basses. I been around way to long. Our Attorney says.."IF I have to defend you in a law suit you need to make it as easy on me as you can" Towing a camper 50lbs or 1500lbs over established specs will not help me out. I did not know or I never had a problem is not a viable defense." That was my decision.. your's is yours'. Let us just , as with any question presented on the forum, present the documented facts. Most of the additional rhetoric, although not bashing or name calling, is not revelant. To sum up...TAKE IT EASY GUYS...

Wrenchtraveller · 03-04-2007, 06:01 AM

I took your advice and deleted my own post. Thanks for the words of wisdom.

Bill Frisbee · 03-04-2007, 06:12 AM

I thought that one way to resolve the debate was to buy a Class A motor home where all options are "duallys". Then I discovered that the debate "over there" is about diesels versus gassers. As Rosanne Rosannadanna used to say, "it is always something!"

What we all need are the "slow days of summer", naps in the hammock under our favorite shade tree, and the return of baseball.

Spring arrives in 17 days and the Boys of Summer are limbering up in Florida and Arizona! Life is good.

Bill

Amps · 03-04-2007, 08:01 AM

Nothing to do with duallies or not but how about...

Parked beside my car this morning was a F150 set up with a 5th wheel hitch.
I took a look and the hitch was at least 1 foot behind the rear axel actually it was halway between the axel and the tail gate. I wondered what he was towing and how safe he was on the road.

virgil47 · 03-04-2007, 08:04 AM

This thread has been very informative and fun to read. I hate to see it come to an end. On several occasions, I have missed having the 4 wheel drive from my F250.

HomeOnTheRoad · 03-04-2007, 08:27 AM

RichFAA gives good advice. It is ok to post facts and opinions but opinions must be worded as opinions not challenges and not saying someone else is wrong and giving dangerous advice. Challenge posts will not be tolerated and will be deleted. It is ok to express thoughts as opinions even when they disagree with someone elses opinion. Use that as the guideline.

ArkieBug · 03-04-2007, 09:19 AM

There's nothing like a good ATC to bring ya back down to terra firma. Thanks Rich.

Wrenchtraveller · 03-04-2007, 10:59 AM

Great so here is my opinion, not my challenge.

You may need a duallie to stay within the GVWR of your tow vehicle if you plan on towing a large Fiver.

You will find that the larger payload that a duallie gives you will allow you to take advantage of all the storage space these larger units have.

You will overload your axle before you ever overload your rear tires with a duallie. With SRW it is possible to overload your tires.

You only have a 7000 pound rear axle on SRW if you have the tires that support it like the 3640 pound rated 18 " tires I have on my F350 SRW.

Your truck's GVWR is a very important specification and adding your two axle ratings will always add up to more than the GVWR. My rear axle is 7000 pounds and my optional front axle is 5600 pounds. This adds up to 12600 pounds and is a lot more than my truck's 11200 GVWR.
To satisfy my truck warranty and the laws of the land, I must keep my weight under 11200.
I have no choice in this matter.

In my personal case, my 06 2955RL makes my truck's GVWR at 11080. Only 120 pounds left before I am over my rating and my V10 is 500 pounds lighter than a PSD.

If my truck had a PSD, I would be overweight with my SRW. My combined rating is 20800 and that is fine. I have posted this many times and this post is for the newer people on the forum.

You will read many posts where people are comfortable being over their truck's GVWR and yet make a big point about being within their combined rating. The logic behind this thinking escapes me.

Combined ratings and tow vehicle GVWR are much easier to stay within when you tow a conventional travel trailer. Because Fifth wheels can put as much as 25% of their weight on the rear axle of their tow vehicle, you must have a TV that can handle that extra weight.

dsprik · 03-04-2007, 11:26 AM

I will apoligize if I offended anyone, or if I insinuated that it is OK to be illegal. It is not legal, and, in fact, also dangerous, to speed, too.

Although I understand the danger of both increasing speed and weight over the legal stated/posted limits to yourself and others is incremental as far as danger, it is not incremental as far as being illegal is concerned, as Don and Bert have stated. If you are over, you are are over.

Thank admins.

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