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Old 09-10-2019, 05:17 AM   #27 (permalink)
Join Date: Oct 2009
Location: Fort Worth, Texas
Posts: 2,442

2004 CTD - '04 DODGE RAM 2500 SLT
Team Cummins
90 day: 19.36 mpg (US)
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Trailer tongue weight (measured; bathroom scale method) MUST be 10% or greater. Stability is dependent.

62-64/mph is more than fast enough. Keeps one out of the left lane. The new challenge is to manage overtaking traffic that they spend the least amount of time alongside.

State law prescribes weight limit for non-braked trailers. Must know weight. Brake actuation must be verified, and the controller set to engage HARDER than the tow vehicle. (TEKONSHA P3 controller minimum acceptable).

The test is that the combined Rig stops FASTER than the tow vehicle while solo.

Find the brake controller setting that does this with the hardest FULL stop AND least amount of trailer tire flat-spotting. (Test again on gravel or dirt).

Find the roads you can do these. It’s not an option. It’s basic. Same with the tongue weight percentage. BOTH need to be “working” to ensure trailer stability.

The contact patch of the trucks rear tires is the emergency allowance. Thus they CANNOT be overinflated. Use a CAT SCALE to get weights with and without trailer, max fuel as you arrive, and with all passengers aboard both times. Consult the Load & Pressure Table for that tire rating and NAIL it down.

A pickup is one lousy tow vehicle. High center of gravity and crippled steering & handling. It’ll roll where a car would spin. MUST reduce hazard. Tongue weight, brake actuation, and tire pressure are basic. (Trailer tires set to maximum).

Knowing ALL weights is a baseline record. Ideally the DRIVE Axle is heavier than the Steer Axle by 10% or greater when Towing. BEFORE one is hitched.

The weight in the truck bed must:

1). Be either atop or Forward of the Drive Axle; and,
2). All gear MUST be secured that in the event of a rollover that none of it comes out of the bed.

Yes, it’s all part of FE. Reduced steering corrections (input PLUS degree thereof) is so serious that both Cummins and Kenworth cite it in their literature.

Driver fatigue affects us all. Please DONT tell yourself you’re better than others at this. First, I’m better yet. So what? The RANGE of skill between all is so small as to be irrelevant. Second, what matters are those moments of inattention to which we are all prone. (Why steady-state on cruise control BELOW commercial traffic is a winner as fatigue takes its toll. No one is exempt). The later in the trip, the greater likelihood of a problem.

TRAILER AERO matters most with ability to handle cross-winds. The lower the profile, the better. Unequal braking action has aero consequences, as does bad trailer axle alignment. (First clue is shot leaf spring bushings; check them).

The gap between the pickup and the trailer is the source of most “bad” aero penalties. But hardest to fix. A deflector MAY help but is as likely to hurt (as Phil noted above).

Ford I-Beam front axle is your aero concern. Zero steering slop ATOP perfect alignment. My 1T has IFS with rack & pinion steering. Which of our trucks will require fewer inputs, brand-new? Which will EASILY surpass the THREE SECOND RULE of releasing the steering wheel and the truck DOESNT head for the ditch?

We don’t want the trailer to wander. At all. We want it “locked” to the tow vehicle. (I can follow you and video the wander. Chances are it will spend the least amount of time in alignment).

As the FORD steering gear type and front end slop baked-in by design gives TERRIBLE feel for what the trailer is doing, it will be too late by the time it’s felt.

Both vehicles can use new Shock absorbers (past 60k on pickup; get BILSTEIN air KONI) and the LIPPERT kit for the trailer. Otherwise, the tires must do two jobs, and this is what will get it sideways. Crow-hop. Shocks are insurance to keeping the tow vehicle tire contact patch undisturbed .

Loss-of-control can come with road surface camber changes, tripping hazards, and slick surfaces. We want EACH tire to maximize grip. Won’t happen with dead or non-existent shocks.

And these corrections makes a long day at the wheel easier. Least amount of I put to maintain headway. Which in turn makes traffic management less onerous. Which in turn means greater alertness throughout the trip.

Whatever the rig, it’ll come back to operator awareness. Don’t think you’ll overcome Rig deficiencies by brute force.

Awareness is diminished with higher speeds. It is NEVER acceptable to be surrounded by others. Cancel cruise and let the idiots sort themselves. Etc.

The vision problem INCREASES with greater speed. Peripheral awareness decreases radically. The “cone of awareness “ shrinks to what’s in front of one.

Too fast if you aren’t aware of changes in the land as they appear. Grasses, soil, etc.

We ease along, manage the idiots to get gone, and reserve our strength.

The framework for this is to execute legs of a trip. One waypoint to another. Plan the stops (same direction of travel, fewest steering inputs to park and then depart, etc). Two hours between breaks is a professional rule. At four hours need a one hour break.

This is how you keep your actions consistent.

Aero is HIGHLY dependent on discipline. The discipline of a higher state of mechanical condition, and the discipline of rules by which to drive. “All cruise control, all the time”, is that example (as too high a speed relative to traffic cuts into it; changing lanes one must cancel it; overtaking too much traffic means cancellation, etc).

There’s a sweet spot in all things: Lane-centered at a dead-steady speed, is where it happens. (Not otherwise).

Now. How embarrassed would you be if I slid into the drivers seat of your truck and proceeded to get better MPG than you? All as above. No differences in rules. A rig I’ve never driven. (I run away from Fords. �� ).

The difference between us is that I’ve been practicing the above for a long time. All I have to do is figure the glide rate of your combined Rig (when off cruise, how long until throttle needed?). Roads you know, but I don’t. Etc.

When I do, it’s in the bag. And I will.

You understand this isn’t about me or you. It’s “listening” to what the truck tells us it wants. We work for the truck. The lowest fuel burn.

Let it drag a little on grades. Roll the downslope slower. Etc. Doesn’t change the trip. Sure as hell changes the fuel burn.

I figure out that roll, you’re toast.

THE TRIP PLAN is likeliest where you’d fail. Poor planning predicts piss-poor performance (greater fuel burn). This is what separates truck drivers. We have to stay two days ahead.

Have a great trip!

And post us a picture with a report afterwards: scale tickets; number of accel & decel events; engine hours against days miles; etc. The more you do as I’ve suggested (some is required) the more obvious it will be to you what you want to do next trip.


Last edited by slowmover; 09-10-2019 at 06:08 AM..
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