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Grit dog

Black Diamond, WA

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Posted: 07/23/20 01:22pm Link  |  Quote  |  Print  |  Notify Moderator

Raife wrote:

I clarified with the owner that the WDH has sway bars. I will observe how he does/doesn't adjust the WDH.

Thank you.


Renting a private party trailer?
Hmmmm. I spose. But ....


"Yes Sir, Oct 10 1888, Those poor school children froze to death in their tracks. They did not even find them until Spring. Especially hard hit were the ones who had to trek uphill to school both ways, with no shoes." -Bert A.

Slowmover

Fort Worth, TX

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Posted: 07/26/20 04:42pm Link  |  Quote  |  Print  |  Notify Moderator

Raife wrote:

Good afternoon. I have read many posts regarding towing



Scale Tickets are the towing baseline. CAT SCALE is a nationwide partner to the truckstop chains and worth having the phone app (go indoors to fuel desk for paper copies). The numerical baseline is also part of the diagnostic tree.

1). How to set WDH
2). How to correct TV tire pressure.

The information needed is the weight per axle. Your first attempt was correct given fuel topped off and driver aboard. The only gear that which is permanently aboard until sold.

a). What was Steer Axle weight?
b). What was Drive Axle weight?

— This is the corrected curb weight. It’s accurate, unlike many junkyard or other scales. Nationwide-comparable.

c). On the Drivers door, what is the Front Axle weight limit?
d). (Same) What is the Rear Axle weight limit?

What is the difference between the scaled value and the limit for:

e). Front Axle:
f). Rear Axle:

We’re up to (6) six numbers needed from the above. (Plus Curb, but not relevant).

That’s the end of the non-problem of “weight” or “payload” issues. Hasn’t mattered since 1967.

First off, tongue weight isn’t payload any more than it’s a constant value. It’s a placeholder number. If at rest — trailer level — full propane & fresh water plus loaded for camping, it is above 10%, and below 15%, it’s good-to-go. The ideal is 12.5%.

It is a placeholder because once underway TWis subject to dynamics of being a vehicle in motion. It is moving up & down AND side-to-side relative to the tow vehicle. It represents the lever-force (leverage) from hitch ball to trailer axle center and never retains the static weight value as measured (except at rest).

This force can exceed several thousand pounds of downward force. Or hundreds when moving upwards. Even more when violent winds force it aside from the TV path.

The purpose of a weight-distribution hitch is to spread this force over the three axles of Steer, Drive & Trailer.

To take the genuinely bad advice of adding more rear spring capacity to a rear live axle vehicle past what’s needed for passengers and their gear is to have gone the exact wrong direction in tow vehicle spec.

A 1,000-lb TW is for cars & SUVs. As once hitched (properly, not as done around here) both Steer & Drive Axles are going to split about 780-lbs between them with spring bar leverage. This same leverage will put the other 200+ lbs on the trailer axle.

The above acquired numbers from the Cat Scale at the outset told us the margin available. . 400# to the front, and to the rear is next to nothing for a car to deal with.

Towing Limits are a laugh. As is SAE J2807 which reveals that automotive enginners have been lying to you since 1965, or they just wanna sell more pickemups.

A pickup is a work vehicle. Unloaded, it’s unstable. Loaded, it ain’t much better. It’s a compromise. Discover the genuine payload. TW is maybe 400-lbs of it. Too high a spring rate means a greater likelihood of a loss-of-control accident as that rear live axle gets airborne damned easily. Trailer towing worsens the tendency.

An LCA is due primarily to adverse winds. Not combined rig weight, and not from trailer weight. A travel trailer has an ENORMOUS sail area, and if a square-edged conventional on leaf springs with a high center-of-gravity (hello, slide-outs) the problem is worsened as it ALSO gets airborne at the stern due to wind forces building (unable to escape).

Typical pickup recirculating-ball steering is dead. Has no feedback. Once a problem is felt, it’s too late to correct.

Adverse winds are sudden gusts. The worst is from passing traffic. Alongside or opposite direction. Add in a tripping hazard (pickups catch air under rear tires as low as 20-mph with not much of a bump or pothole) and it’s over in under one-second. Barely 100-feet traveled.

The short version of good hitch rigging is that the tow vehicle will be able to resist side-sway. This means an ideal of: low center of gravity, wide aspect tires, and independent suspension. Short rear overhang (rear axle distance to hitch ball). The vehicle with these features is hardest to side-slip.

TV weight loses any advantageous margin once above 4,000-lbs. After that, it’s fighting itself. Same with wheelbase. High speed steering is maxed with 122” WB. This has been well-known since the earliest 1960s when Dodge altered its entire full-size fleet to that WB after the LA County Sheriffs Dept and CA State Highway Patrol conducted extensive testing. It’s why a 1969 Dodge Polara Police Pursuit and 2019 Dodge PP have the same dimensions & basic weight. “More” isn’t better . . . it’s a handicap.

A tow vehicle basically at 50/50 FF/RR weight balance before being hitched is a starting point. Once the WDH hitch is tensioned, the additional weight (think instead, the more accurate term of force is the same front & rear.

The priority for safe travel is:

1). Steering
2). Handling
3). Braking
4). Throttle

To read RV forums is to believe the opposite order. TV advertising, the RV echo chamber, and failure to perform tests an ordinary eighth-grader can do results in tow combinations so bad that “vacation” turned into work. Travel at a higher risk than was ever necessary.

The later Durango shares the same IS & unit-body design of the Grand Cherokee. Both advantageous. Wheelbase is okay. It’s the short rear overhang that puts it in good position, live rear axle or not. (Tires should be Highway-spec. Michelin or Bridgestone. Bilstein or Koni Shocks).


Want to live a long life? Drink to excess, smoke 3-packs a day, use illegal & prescription drugs indiscriminately, gain 160-lbs, then make job hopping a career and leave behind a string of divorces. Have an admirably long arrest record.

Because to avoid being gunshot or in a serious car accident is the main predictor . Those two change the statistics for long-term survival with no peers. The “bad habit” and “bad character” categories aren’t even close in deadliness.

Bigger truck (bigger TV of any sort) isn’t better. It’s worse. “Faster up the grade” is laughable (it’s the downslope that matters). Bigger truck has WORSE brake performance, not better. (Guys too dumb to upgrade trailer brakes to antilock disc).

The best tow vehicle is the one which best suits family duties (low-risk design). As maybe a quarter or third of annual miles will be towing, an upgrade of what presently works well (not ego, vehicle design) is adequate.

Short version of that is one with fully independent suspension & short rear overhang. Car, van, SUV.

Understand that on RV forums are otherwise well-meaning, but ignorant people who’ve never experienced much less ever set-up a very good towing rig. 15 or 20 years worth of (thus far) good luck thinking they’re “experienced”.

Takes but once. (No replay. No rewind).

The RV forum typical, “You gotta have a pickup”. Maybe if it’s as an IRS-deductible business vehicle (farmer, rancher, contractor). Any vehicle above suited to family and to tow (in other words; of them) can also pull an open deck trailer that’ll carry more than any pickup can. It’s the worst vehicle design

The real problem with travel trailers isn’t their weight. That’s another 30-40 HP at highway speed. Irrelevant. The problem is in their design. High off the ground (these days) genuinely bad suspension, and the aerodynamics of a brick.

7,000-8,000/lb travel trailers are what a (police car in civilian mode) can tow. Covered all of the US, most of Canada and a good part of Mexico in cars pulling TT of THAT weight growing up. Family of five. Car only lasted 190,00-miles before being sold to a guy hauling race cars who still hadn’t opened the engine at 240k. One trans rebuild. Second brake job just before sale.

That was the first dozen years with that TT. The next eighteen was with another TV also sold at around 200k. Trailer sold after 30-years of use. It’s still on the road at age 45.

1). How long will you own the TT?
2). How many miles per year do you expect to travel additional to current work & family needs? (Average RVer is 5k extra on top of 15k typical).

The quality of both vehicles matters greatly if any extensive travel is considered. The typical square box trailer lasts ten years or about 70k miles. My current TT turned 30 last fall. 25-years or 250k miles is about average prior to some restoration. Airstream was the entry-level aluminum trailer. Only survivor of a better era as it became the prestige brand of THOR. Many thousands built. Huge following. Best towing trailer ever built. Depreciation bottoms at about 10-15 years. That’s the point to grab one. (I’d have a cutoff of about 1996). Quality greatly higher than all others today.

Besides testing failures — and besides ignoring the most important role of a family vehicle — the point to travel is also forgotten on RV forums: to sight-see in a new region. A pleasant-to-drive car or SUV beats a long & heavy, bad-handling pickup on any day-trip. That’s where most of the miles of a trailer-trip accumulate.

You’ll see plenty of nay-sayers to the above, but note they can’t back their assertions (no tests) , haven’t the multi-vehicle experience, lack the fifty-plus years (third generation) of travel this way, and also don’t have the 10,000-miles per month I do as a long-haul trucker.

Commuter miles don’t count once you are on the open road. Today’s drivers without exception are worse than they’ve ever been. Twenty years ago those exceptions existed. They do no longer. No one here would willingly have me as trainer. There almost aren’t even truck drivers excepted from the ranks of the pitiful any longer. Yet the 2-3 basic rules have never changed. (A demonstration would suffice, and some analysis tools blow holes in childish ego).

You’ll do what you will, granted. But there’s more (much more) than what TV ads, misleading dealership & RV forum “information” to be found and used.

Take your time. Read widely & broadly. What works is the physics a middle-schooler can deal with, so it’s not difficult in & of itself. It’s parience, and discipline.

A Durango isn’t limited by the numbers thrown around here and elsewhere in RV fantasy land. It’s more than suitable. Get real numbers, and work with those. Guesstimates and “tow limits” and “payload” and “tongue weight” will take you and your family on the dead-end highway in the dark.

The important choice is the trailer design. All else is second. That said, TV & TT together are almost as important as the hitch rigging.

But this is not represented in a separate sub-forum. Nor is trailer-braking. That they are missing is the biggest clue of all.

Good luck

* This post was edited 07/26/20 05:04pm by Slowmover *


1990 35' SILVER STREAK Sterling, 9k GVWR
2004 DODGE RAM 2WD 305/555 ISB, QC SRW LB NV-5600, 9k GVWR
Hensley Arrow; 11-cpm solo, 17-cpm towing fuel cost

TomG2

Central Illinois

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Posted: 07/26/20 05:25pm Link  |  Quote  |  Print  |  Notify Moderator

Lots of opinions that get passed off as knowledge on these forums. There are the "Rear Axle Weight" guys who insist that a stouter rear axle creates a towing monster out of dog. There are the Airstream folks who remember how well they towed with a 1958 Buick. Some truth being used to validate opinions is quite common. Nobody is right all the time if they are wrong some of the time. To the OP: Take all the opinions with a grain of salt. Keep doing your research and error on the side of safety. When someone tells you that you have to do it their way, tell them to get out their checkbook.

Raife

Texas

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Posted: 07/26/20 07:18pm Link  |  Quote  |  Print  |  Notify Moderator

Slowmover - thank you for all the info. It will take me some time to work through and digest it all. A couple quick notes though...

1) I am not interested in maxing anything and I never believe adverting numbers

2) My Durango first and foremost is a family hauler

3) The Durango lists the GAWR Front: 3200lbs and GAWR Rear: 3900lbs

4) You mentioned Steer and Drive axle which I'm not sure I can differentiate the drive axle completely as mine is AWD (Steering is obviously the front axle). That said it is rear biased.

5) I did use CAT scales to ensure I got an accurate number, but I did not get weights for the front axle and rear axle (i.e. I was on a single plate on the scale).

6) The window sticker says "Rear Load Leveling Suspension" but I have no idea how effective it is...I'm not particularly interested in adding spring capacity.

7) I have Pirelli Scorpion Strada tires - 10 months old, 9,500 miles on them

8) You mention trailer braking, I installed my Teckonsha P3 yesterday in prep for our long weekend trip coming up (trial before the long one in a couple months)

9) We are renting for this coming trip and had planned on renting for the long trip, but may consider buying since the rental would be about 1/6 the cost of buying a decent used TT.

Thank you again!

Grit dog

Black Diamond, WA

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Posted: 07/26/20 09:04pm Link  |  Quote  |  Print  |  Notify Moderator

Some good albeit some debatable info from slowmover.
But don’t overthink it. Keep it to around a 5klb x24’ long trailer and you’re good.
Pump your rear tires up to max, let the self leveling suspension do it’s thing. I’d test that first to see what it’s good for.
Adjust the trailer brakes and wdh once you get the trailer on and go.
One tricky thing is you can’t just adjust wdh by height as the self leveling won’t let the rest squat.

TomG2

Central Illinois

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Posted: 07/27/20 07:22am Link  |  Quote  |  Print  |  Notify Moderator

You can always tell a fake expert when they resort to calling other people "Stupid" or "Dumb". Some might question how many travel trailers actually take flight when going down the freeway. "gets airborne at the stern due to wind forces building (unable to escape)." I have seen a lot of trailers on the highway, but none became airborne from the lift involved at ordinary speeds.

When it comes to undocumented claims about mileage etc. I have one too. Our 1951 Nash Statesman got 34 mpg since it had an overdrive transmission.

lane hog

Tucson, AZ & NW Chicago Burbs, IL

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Posted: 07/27/20 11:49pm Link  |  Quote  |  Print  |  Notify Moderator

Steer and drive are just another way of saying front and rear axle.

Personally, if you're entirely new to this, I'd stick with rental if it's an option for the longer trip. You won't know what you want for a RV as a family after one trip.

Renting isn't cheap, but neither is losing money on an RV that you buy and realize doesn't quite work for your idea of camping. Either you'll sell it at a loss, or you'll be trading up at a loss to get something else.



  • 2019 Grand Design 29TBS (had a Winnebago and 3x Jayco owner)
  • 2016 F-150 3.5L MaxTow (had Ram 2500 CTD, Dodge Durango)
  • 130W solar and 2005 Honda EU2000i twins that just won't quit



Raife

Texas

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Posted: 07/28/20 06:42am Link  |  Quote  |  Print  |  Notify Moderator

Yep, I have not made any decisions on the purchase, but the rental would cost ~$2,500 and the trailers I'm considering are ~$15,000. So even if it is "wrong" and sell it for at least ~12,500 then it is sort of a wash. (I understand the math is not quite that easy)

I am also struggling to find a reasonable rental for the time frame of our long trip. Once we factor in the time frame, duration, and acceptance of a pet the choices dramatically decrease.

For examples this is one that I found through a quick search:
https://www.rvtrader.com/listing/2020-Jayco-Jay-Flight-SLX-8-264BH-5013321317

I would need to do a lot more research before purchase (and asking questions here) and factor in anything we learned during our first trip.

Thank you.

Mickeyfan0805

SE Wisconsin

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Posted: 07/28/20 07:47am Link  |  Quote  |  Print  |  Notify Moderator

Raife wrote:


For examples this is one that I found through a quick search:
https://www.rvtrader.com/listing/2020-Jayco-Jay-Flight-SLX-8-264BH-5013321317


Your rental experience might give you some sense of this, but I would encourage you to be a little weary of that much length. Some might throw out hard and fast ratios on wheelbase vs. trailer length, but most of those seem to have origins in the opinion of some blogger or commentator. I've yet to see a formal guide on length published by any recognized manufacturer of vehicles or trailers - so this doesn't have a way to 'crunch numbers' as you can with weights.

That said. 29' is a LOT of sail to put behind the short wheelbase of a Durango. Furthermore, such a light trailer at that length is going to be pushed around by wind that much more easily. Weight is essential, but I would suggest that you will find that much length to be too much to comfortably control with a mid-size SUV.

Raife

Texas

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Posted: 07/28/20 08:53am Link  |  Quote  |  Print  |  Notify Moderator

Those are excellent points...I have mostly been working numbers on weights to ensure I don't over burden the vehicle (i.e. my published tow weight is 7,200lbs but I calculated out that 6,000 was the limit given TV GVW, passengers, and tongue weight).

I also believe the 29' is tongue to tail and the "sail" portion is 26' (could be wrong). Not this makes a huge difference...

Most trailers I see with bunk options (I have 3 kids) are in solidly in the mid to high 20's on total length and mid 20's on "sail" length.

* This post was edited 07/28/20 08:59am by Raife *

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