[slowmover]

" . . The majority of my driving is north south driving and living in the midwest with lots of farm fields I have a lot of cross winds. Does an aero cap help hurt with cross wind drag?"

Commercial electricity production with wind turbines depends on a high average wind speed. Where I live and drive is such a place. Spring time crosswinds travelling north-south remain constant in the 20's and higher. Some days the average stays up in the thirties with gusts into the 50's. So this is a topic of familiarity, not just of interest, to me. Driving in such a headwind beggars belief as to fuel consumption . . . one is effectively "doing 90" in such scenarios while dropping recorded speed to around 50. Watching high profile vehicles heel over like a sailboat is a common sight.

What I've found is this: the steps taken to maximize fuel economy, but not to lower the ability of a pickup truck to do work (otherwise there is no point to having one) shouldn't be sidetracked, much less de-railed over this concern. After all, one's goal is the percentage improvement to the annual average mpg. If that is on track then seasonal variations aren't much of a concern (I could see where winter driving could conceivably exact a greater penalty).

However, there is no doubt that increasing sail area can have a decided effect on handling (meaning steering and braking). I would say that going after steering slop and upgrading [preferably] to KONI or BILSTEIN shock absorbers is first on the list as are polyurethane anti-roll bar bushings. Bringing steering corrections per 100-miles to a minimum -- no matter the driving conditions -- is the immediate goal. As with braking, where duration and degree can be minimized in keeping upright and lane-centered, changng sidewinds (now present, now gone) and most especially from a 3/4 angle to direction of travel is the condition at which to take aim. This, not sidewinds, is the main FE degradaton culprit.

Towing opens another can of worms (greater vulnerabilities to wind, natural and/or man-made), but the above approach is the beginning of thinking, IMO. I would not assume that vehicle alignment is correct even if new, nor that brake drag is not occurring, beyond steering slop (see "tolerance stack" as a discussion). Have them verified. FE is just part of a larger puzzle of pieces whose shapes must be known.

A numerical baseline is what is called for on any vehicle, and more so on a pickup (the tendency to rollover, not spin out as with a low COG car; statistically this is not a skill question). To that end I would weigh all four corners of the truck as equipped for travel and adjust tire pressure on that basis alone. Chasing another tenth via too-much tire pressure is the wrong way where it contradicts safe operation. The vehicle manufacturer offers guidelines to this end (drivers door placard). Use that for a constant in gauging "lane-centeredness" .

To now take this discussion to a higher level -- the work capable by a pickup truck -- I would like to strongly suggest that testing be done with the truck at or near GVWR. This will highlight any flaws in the approach. As most of what goes on around here is just a game in what a solo driver in a somewhat modified car can do on the morning commute and does not take into account knowing fuel burn under under all condtions, one is well-advised -- as I see it -- to put that trucklet to the test. Otherwise, why a truck?

I've recently received a larger front anti-roll bar and a new rear anti-roll bar (where none previous existed) and will likely add a Panhard rod to the rear axle to minmize forces introduced by winds and in towing. Yes, increased sail area is noticeable at the wheel with my cab-height LEER cap. Movement of the body relative to the axle is noticeable. For a pickup, any change that increases the chance of oversteer is not to be undertaken without changes to driving style.

This is discipline moreso than skill acquisition. I drive solo as if my 9k trailer were always hooked up. Not perfectly so, but generally so. I believe my default habits should always reflect longer stopping distances, etc. This in no way contradicts driving best FE as I see it, even if some of the stupid practices (tailgating big trucks) are left out.

As my trucks adjusted "empty" weight is now 1,000-lbs higher than the as-delivered condition, suspension/steering changes are being made. FWIW I would much like to have an "Aerolid" with a bedslide. I can make the load fit, even if COG changes are likely. 66-mph is my top speed, and 58-mph is my preferred speed, even on 80-mph Texas Interstates, solo or towing. Pickups are handicapped. As yours will change, so will its' reactions.

Take a wide-angle snapshot. Acquire empirical numbers. Make changes on that basis. Be able to predict fuel burn under empty and loaded conditions. Account for weather whether temps or winds. How far can you reasonably travel given 80% useable fuel tank capacity? What is the cost to travel X-miles with Y-fuel at an average speed (another area of understanding crucial to a pickup truck as it is well under the stated travel speed.)

This is the goal of a pickup truck: Is it cheaper for me to make a round-trip or to pay shipping? What price convenience? An Aerolid is leverage to the weights of that question as pickups are cheap to buy, but highly expensive to operate. Fuel is not much more than a third of that question if understood correctly as the scope is greater than immediate costs. The dollars at stake are also future earnings capability, thus it is more than just "money".

Good luck, and look forward to more.

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