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 > How to avoid getting blown all over the road

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JRscooby

Indepmo

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Posted: 05/12/21 03:22pm Link  |  Quote  |  Print  |  Notify Moderator

2oldman wrote:

One nice thing about a Freightliner M2-106 MDT. Hardly notice wind at all.


Well, my 106 inch cab Freightliner, with 20,000 steer, 22,000 lift axle and a pair of 23,000 drive axles could tell the driver when wind was pushing the side of the 17 ft long, 6.5 foot deep empty open topped bed. Add 30 tons of gravel in the bed, wind was less of a issue.

BackOfThePack

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Posted: 05/13/21 05:33pm Link  |  Quote  |  Print  |  Notify Moderator

MyersAvionics wrote:



The dealer hooked up our hitch when we purchased the camper. They very well may have not done it correctly. I never redid their install. I will be taking my time when I receive the ProPride next week when I install it to ensure it is done correctly.


I bought the hitch type in 2007. All other types are obsolete. Given that an effective towing combination is one-third each TV-Hitch-TT, it’s a dirt cheap hitch.

You’ve moved to an an effective steering component versus the other types which — while they might distribute tongue weight to formula — can resist but not eliminate mis-alignment between TV & TT.

Trailer MUST be dead-level after hitch roughed in at home. Use a level in doorway FF-RR. Bubble mainly in center. TV might be slightly tail down which is normal. This may take time AND may involve using a shop. “Slightly nose down” IS NOT acceptable. Trailer braking is DEPENDENT on having both axles equally loaded per attitude PRIOR to braking onset.

Still need to do The Three Pass Scale Method. Get the CAT SCALE app.

First step is corrected solo tire pressure. (I run the same tire pressure solo or loaded as it’s the right number per door sticker and L&P Chart). Checked morning dead cold after overnight; recorded. After topping fuel tank on the truck where ONLY permanent gear + driver is aboard the baseline number is acquired. This reading also gives the lightest weight of the truck.

The TT needs to have full fresh water + propane. Tires to sidewall max for test. Gear aboard TT & TV should represent a camping trip. Top off fuel tank first. All passengers aboard each step. All three must be done together.

1). Across scale with bars torqued.
2). Across scale with bars slack.
3). Drop trailer and weigh TV solo.

— Steer Axle should be the same in #1 & #3.
— TW can be accurately determined.

Another reading can be done which ought to be “mandatory” on a toy hauler: sliding axle. Talk with weigh-master at Fuel Desk. This is where the trailer axles are split onto two scale pads. One creeps forward until STOP is heard across Intercom. This procedure gives you the INDIVIDUAL axle weights.

Toy Haulers are compromised designs. Do what you can to get axle loadings close, AND TW inside 10-15% (higher better but harder to adjust WDH). 13% GTG.

Test: at 30-mph in a hard stop the combined rig WILL stop faster than the TV solo (camping loads; same day). If it doesn’t, start with brake controller settings. Trailer must lead TV.

The wind load (crosswind) against a tall unbalanced trailer is significant. Squared edges means winds can’t escape (aero they do; Airstream). Second is unnaturally talk ride height to accommodate slides, etc. Wind getting UNDER trailer sideways is adding PULL to PUSH.

The trailer WILL start to get airborne behind the axles. All the forces increase on the square as one moves farther rear. This is how 18-wheelers get knocked over. In high wind areas drivers will pull the tandem axle set on a van to the rear (despite weight imbalance and laws) to help resist crosswinds. Loaded weight helps (30-44k in the box), but realistically one must slow to 45-mph to maintain headway and keep wind pressure minimized.

The Game is actually at the TV. The Drive Axle. IDEAL tire pressure is crucial. Too high means it will lose traction sooner, and too low means lousy braking & steering plus high heat (premature failure). Dead-on and the tire lives long and provides best traction in all conditions.

I run my pickup at the RR GAWR once hitched. Before being hitched it’s within 40-lbs at all four corners. The most weight on the Drive Axle to keep the highest load in the tread patch. Together, the combined tire patch on that axle is small.

The trailer suspension is what’s left. Leaf sprung is pretty much junk in resisting side forces. Narrow track (where axles attach, NOT tire distance), incredibly short wheel travel (okay on an open construction trailer, NOT on a tall tippy RV). DEXTER Tor-Flex is a needed upgrade (or MOR-Ryde offerings; axle replacement).

Trailer anti-lock disc brakes crowd a PPP hitch hard for which is more important.

* This post was edited 05/13/21 05:56pm by an administrator/moderator *


2004 555 CTD QC LB NV-5600
1990 35’ Silver Streak

JRscooby

Indepmo

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Posted: 05/14/21 06:12am Link  |  Quote  |  Print  |  Notify Moderator

BackOfThePack wrote:



Only 1 line I can disagree with

Quote:

— TW can be accurately determined.


The most accurate TW that can be determined is what you get when you compare weights of steer+drive in pass 1 and 3.
If you need a WDH, the nose of the trailer will be low when the bars are loose. And as the tongue goes down weight is transferred from axle to tongue.
But that does not matter, because the percentage TW that matters is what you get when ready to drive.

Pass number 2 gives you more numbers, sure. But very many people have issues working with numbers, let alone deciding what numbers they need to solve the problem
1). Across scale with bars torqued.
2). Across scale with bars slack.
3). Drop trailer and weigh TV solo.
Now maybe somebody reading this might think I must be wrong because so many want pass 2. The only reason I can see to want those numbers is they do not believe the weight distribution tongue/axles change as the tongue is lowered. If you believe moving something/anything from behind to in front of the axle changes the TW, a simple diagram can prove it.
Lets start with a side view of single axle trailer. With the trailer set at any given slope, front/rear, draw a vertical line thru center of axle, mark that line on side of trailer. Now lower the tongue. When you draw the vertical line there is a space between the lines. If you can see the lines as planes, there will be a wedge-shaped area that moved from behind to in front of axle. Now how much weight is in that wedge? I'm not smart enough to figure, but I know it is not 0.
Now for a multi-axle trailer, the picture is more complicated, but there will be multiple lines, but there will be a wedge that moves in front of front axle, and another wedge that moves in front of last axle.

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