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Old 08-30-2019, 01:05 PM   #11 (permalink)
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Trailer is not finished yet but did get all the cross braces welded, did some test fitting for tie down attachments on frame, adjusted/welded fenders on, last night sanded and wire wheeled/ repaired some older bad factory welds. The tires are used d rated truck tires 225/75r15 rated for more than 70mph. I thought about getting brand new st trailer tires but I was trying to keep cost down and figured these are about 5 years old with no cracking and rated above 2.5k each at max psi but the side by side weighs 1725lb stock maybe 100lb more with spare tire, jack, 2 gallon fuel, and few tools. The trailer has tandem 5 lug axels. figured im under 3700lb trailer/cargo combined.

truck/trailer speed limit here is 65mph but most trucks go almost 70. If I try anything under 65 I'll have more people on my tail than flies on fresh cow poo. We have a lot of single lane highways where im at in North Idaho and not many pull outs except for run a way trucks on hills and truck stops but I feel good at 67mph. Keeps my rpms lower and people off my tail most of the time lol.

The truck is a 1999 f250 auto, 7.3 diesel, supercab shortbed 4x4 with a leveling kit and 285/75r16 tires with a aftermarket trubo compressor wheel, larger transmission cooler, straight pipe 3.5in exhaust, and a bed cover (easily 1-1.5mpg boost on road trips with that thing and no trailer). I have whats called a php hydra chip that changes the ecm settings. I have a 25hp heavy tow tune that works amazing when im towing the 5th wheel or small equipment. Really helps keep the truck in the powerband but doesn't do anything for fuel economy so truck is in stock mode 80% of the time.

I guess it may be a while but when the trailer is finished enough to at least put the side by side on i'll snag a picture and post the height, length of truck, trailer, trailer with side by side and stuff.

really appreciate the good info. It may not be worth adding skirts or anything to the trailer but ive got plenty of scrap steel/wood so i'll try lol

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Old 08-30-2019, 02:55 PM   #12 (permalink)
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Technically those "Truck" speed limits don't apply to you, even a F250 pulling a large trailer is still a "light duty" truck. That said, I'm just across the boarder in north western Montana and will drive 55 all day if I want. People pass, I use pull outs. If I go much faster I'm going to end up on somebody else's back bumper. Then what? Have to pass them?
55 saves a ton of gas pulling a giant sail of a camper we have, it saved a ton of diesel when we used a Cummins. I'm also seldom in a hurry to get anywhere towing, it's called a vacation, and I want every minute to be relaxed.
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Old 08-30-2019, 03:18 PM   #13 (permalink)
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67 on those mountain twisties sounds bad enough, let alone adding 5k worth of trailer behind. If your tires are rated for the speed they'll handle it, but I'd still slow down if I were you.

Aside from the aero help, that diesel will thank you big time if you keep the RPMs down a bit.

Edit to add: the "truck" speed limits only apply to commercial vehicles, a 3/4 or even one ton pickup is not a truck, no matter how auto companies like to advertise and sound tough.
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Old 08-30-2019, 04:47 PM   #14 (permalink)
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Quote:
Originally Posted by Hersbird View Post
Technically those "Truck" speed limits don't apply to you, even a F250 pulling a large trailer is still a "light duty" truck. That said, I'm just across the boarder in north western Montana and will drive 55 all day if I want. People pass, I use pull outs. If I go much faster I'm going to end up on somebody else's back bumper. Then what? Have to pass them?
55 saves a ton of gas pulling a giant sail of a camper we have, it saved a ton of diesel when we used a Cummins. I'm also seldom in a hurry to get anywhere towing, it's called a vacation, and I want every minute to be relaxed.
I think you are right. I spent 10yrs through the military in CA and their truck speed limits apply to anyone with a added tow axel so I got used to that. There are very few roads in my area with a less than 65mph speed limit so im not gonna be that guy and constantly have to pull over to only get 2ish mpg more max with my truck. I do slow down for hills, take it slow on corners when necessary etc. Ive been towing equipment and trailers up to 48ft for good amount of time so I feel my driving is pretty conservative esp when loaded.

Quote:
Originally Posted by Shaneajanderson View Post
67 on those mountain twisties sounds bad enough, let alone adding 5k worth of trailer behind. If your tires are rated for the speed they'll handle it, but I'd still slow down if I were you.

Aside from the aero help, that diesel will thank you big time if you keep the RPMs down a bit.

Edit to add: the "truck" speed limits only apply to commercial vehicles, a 3/4 or even one ton pickup is not a truck, no matter how auto companies like to advertise and sound tough.
agree with the truck speed limit. Old habit from a bad state I spent a good amount of time in. I usually do go over 65 loaded anywhere just because of the added fuel consumption but 65 in the areas I drive seem to be the right blend of keeping people off my tail, keeping good distance from those ahead of me, sometimes I can even time traffic lights in congested areas but most of the time they fly around/ then in front of me so I just stay back and let them fight for the seconds saved lol.

Im gonna do some more work on the trailer tonight. May even be able to load the side by side on it to take some measurments. Probably next week the unit will be 100% though. Appreciate the info/thoughts. hoping to post a pic for your input soon.
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Old 09-01-2019, 09:36 AM   #15 (permalink)
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Understand trying to "go with the flow". I do it too, both above and below ideal speeds. In Washington, the truck speed limit and the maximum speed is 60 for a huge part of the highway system from Olympia to past Everett, so it is pretty easy to take it easy
Get out toward Idaho on I-90 and it gets just like you say, big distances and people in a big hurry. I find a trucker with a light load and cruise control, and shadow him at a safe distance.
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Old 09-02-2019, 09:46 AM   #16 (permalink)
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If those tires are five years old, time for new.

Tires that sit, dry rot. Heat from use is NEEDED to keep them in shape. The expectation is 3-5 years tops. Mileage not a trailer tire life consideration.

As to rig aero, the truck bed needs a cover. A thin piece of plywood extending from tailgate to 1/2 the distance to the cab.

As to MPG, it’s about steady-state. Below the flow of commercial traffic. One uses mirrors to manage their getting around your rig ASAP (slowing to accomplish this when they have less than a 5-mph variance). It’s a different set of habits.

The “goal” is maximum distance from all other vehicles throughout the day while still on cruise control. No lane changes (which means sub-65 travel speed).

A cruise control set of from 62-64/mph is as high as it gets. Then, monitoring traffic. With a jam of vehicles up ahead moving more slowly than this, one backs off in speed until it clears. It will. Always does.

Same with any passing. Done when alone. Only.

The relationship between Average MPH and Average MPG is the fundamental. Use engine hours against the day’s trip length for the former.

It’s a rude awakening for those who believe a speed like the above is too slow. As a faster speed that causes one to have to pass more doesn’t result in a faster trip time, per se. The few extra minutes “saved” means MPG gets a broken jaw.

Traffic volume (road design plus other conditions) dictates travel time. Not set speed.

A few mph extra can show NO BENEFIT, only deficit. I do this all day, every day.

In short, if there’s ever a time you’re within a football fields length of someone else, you need remedial instruction. (Heard the phrase, “cant fix stupid?” That’s the guy surrounded by other vehicles).

Safety trumps MPG, but, happily, they track each other most all the way.

Along with engine hours & odo reading at day’s beginning on a note card, also set categories for braking and acceleration events. Mark each one. If you’ve slowed to get someone around you faster AND can use a downslope to regain set speed, that doesn’t count against you.

The “ideal” trip has only one each of those events. Absolute zero idle time. The trip is from when parked from overnight, until being parked for the next night. All miles & time. Not highway only.

Planned stops only. And then, only after the original first two hours at highway speed (as this is the initial warmup and lessens re-start penalty). Make the stops at locations in the same direction of travel, and with fewest number PLUS degree of steering inputs. Etc. (These details matter greatly).

On the vehicle CONFIRM perfect alignment (Ford always a problem), trailer axle alignment, and that trailer brakes & bearings are properly adjusted. Trailer tire pressure should be to sidewall maximum. Truck tires are from a CAT SCALE weigh ticket and consultation of the Load & Pressure Table of that tire ratings category. (Inside vehicle manufacturer range). Not higher or lower as that worsens handling & braking.

One is also looking for caliper drag on the tow vehicle. And, with a turbodiesel CONFIRM no CAC leaks.

Seat posture is that ZERO reach is needed to the top of the steering wheel. Arms not at full extension. Mirrors adjusted accordingly. Driver fatigue is the thing. Everyone is affected. A bad seat cushion, as example, needs remedy. Alertness throughout the day is what preserves those tenths of a mpg.

Any aero with the trailers contents is worthwhile. But, first, CONFIRM that the trailer tongue weight is more than 10% of the trailers total weight.

At the CAT SCALE, do two passes after topping fuel tank and keeping all passengers aboard:

1). Rig as hitched.
2). Truck only.

At home prior to this, find a copy of the trailer tongue bathroom scale weighing method. Numerous sources. Find the empty and loaded values. Use a carpenters level on trailer to have it dead level when weighing.

To hitch the trailer one needs it as close to level as possible. A half-bubble out is almost too far. MASTERLOCK and some others used to sell an infinitely adjustable hitch that makes trailer leveling easy for under 5k of load. I bought mine at U-Haul. It’s an Acme Screw. One uses a box wrench to raise or lower.

MPG is a question of details. If you truly want it, then one has to chase them. An alignment good enough to get down the road ISN'T the same as ideal, for example.

Just as driving more slowly isn’t enough. It’s the totality of every input the truck receives through the day. Less is more.

As an example I’ve hooked up U-Hauls largest enclosed trailer and with a combined weight in excess of 13k still seen above 18-mpg towing on two separate trips of 350-miles. On a the truck below in signature, where, with almost a quarter-million miles is just finishing its second set of tires and has had one brake job. 50/50 Town & Country miles, it was spec’d with FE in mind.

MPG is a GREAT way to chase down details. See contributor Big Dave’s many Ford posts here, and see his Fuel Economy subforum on one of the Ford enthusiast sites.

One has to have a plan. Records. Baseline numbers.
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Last edited by slowmover; 09-02-2019 at 10:21 AM..
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Old 09-02-2019, 12:20 PM   #17 (permalink)
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Slowmover, your post should be on the bulletin boards of all commercial freight haulers who give-a-fig about economy and safety!
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Old 09-02-2019, 03:01 PM   #18 (permalink)
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Doing it for a living lends focus. I’d imagine you'd have written the same with a shared background. Industry literature, training, and shared observations are the other part (talking shop). One can “test” almost any proposition on a daily basis. Driving is always of interest.

Aero is fun because it’s flat cool. Measuring it is the problem when mechanical condition or operator error cloud the picture.

I’ve noted before that I’d bet money on the sensitivity at the wheel of both BamZipPow or Aerohead (not to exclude anyone) as the depth of aero modifications highlights ANY other problem.

The rest of us are fatigued by wind noise and ennui. Takes a trip of substantial miles to get use-able numbers. Those two rigs (and any similar) are such that in 25-miles or less they have distinguished between mechanical & aerodynamic as to needed changes. Rome wasn’t built in a day.

Race cars.

For the rest of us — and especially those of us with used vehicles — what’s necessary is of a higher standard than most cars with good owners receive.

In the end, MPG (as with tire & brake life) is an indicator of longevity. Reliability. Putting safety first actually makes a longer day easier. Less effort expended. Thus the same end is served.

The best trip is one that is forgotten before one falls asleep. The scenery or other pleasant sensations needn’t be tied to a particular route over a particular day, after all.

The willingness to use records henceforth, and occasionally test, is what creates the improved annual average mpg (expressed in cents-per-Mile). Repairs, maintenance and driver habits are at issue. Emotions about money & self.

“Success” is the percentage reduction.

Now, will that be in reduction of total annual miles? (Greatest effect, and easiest to achieve). Or, in reduction of fuel burn per mile (maybe greater satisfaction, but harder both to quantify and to achieve).

As to a vacation, it’s been about ten years since I posted it, but it’s possible to underwrite nearly all or most vacation travel by diligence the rest of the year.

Anyone up for 5,000-miles of free fuel towing a travel trailer on vacation?

I was aware of — but hadn’t thought through — the discrepancy between highway & city mpg until Diesel Dave made it a challenge: close that gap!

So, we’re all just sitting around having a cold one, MG.

.
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Old 09-04-2019, 03:16 PM   #19 (permalink)
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slight update. I have 5 Carlisle 225/75r15s arriving tonight. Going to check, clean, re grease wheel bearings soon. Im staining the trailer deck material today after work and doing some more paint prep work.

I run with an adjustable hitch and try to get the trailer level. we also welded up the anchor points on the trailer so that the side by side sits where it needs to for tongue weight/balance etc. Im not totally ocd about mpg as sometimes I don't feel like going 10-15mpg under the speed limit even with no one around but I feel I drive safely and much safer than many of the folks around me. I only let the truck idle at a minimum for the turbo to cool and use the block heater/full synthetic oil for winters (made a huge improvement by the way) I was burning way to much of the rotella t6 5w-40 so Im trying the newer t6 15w-40 in full synthetic this winter. I burned about 1.5quarts in 5k with conventional 15w-40 but that nearly tripled on the 5w-40.

truck has zero external leaks and I have resealed the fuel bowl/filter housing and fuel lines, replaced seaping high pressure oil pump lines, all new hoses for just about everything. Im more ocd about maintenance and its paid off over the years. many 20+yr old vehicles I have run just great just don't have all the touch screen stuff.

I check air pressure every couple of months but I do a walk around and my wife still pokes fun of me but I've caught low tires and leaks that way many times.

Appreciate all the great info and again making progress so hoping to post a pic with measurements.

my towing mpg seems pretty consistent. I use diesel kleen in the winter and that actually helped a solid 1mpg with winter cut blend.

me towing around 8k with the equipment trailer around 14mpg avg, city/highway.

me towing around 12-15k 8-12mpg. big 5th wheels drag a lot and lumber just is heavy for a single rear wheel 7.3l diesel with an auto.

me towing under 4k honestly 16-17+ mpg easy on highway and around 14-16 combined.

I run the tonneau cover when im empty and it paid it self off with ONE ROAD TRIP LOL. couldn't believe all the stuff I learned in a few days here lol.
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Old 09-05-2019, 11:22 AM   #20 (permalink)
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Not doing that bad, you're just below my "retired"18 mpg average in city with a 6 speed driving like an old man with a hat.

Check your calipers for drag after release, they're famous for that, my rr is showing signs.

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