Fleet Fuel Saver Blog

Hills, Shifting and RPMs On The Highway

admin — Thu, 07 Apr 2011 17:16:44 +0000

The wind drag created by conventional mudflaps is especially noticeable on the ascent and descent of hills at highway speeds. Eco-flaps can delay or even eliminate the need to downshift on the uphill side because the engine is not having to overcome the additional aerodynamic drag from the solid flaps to maintain sufficient RPMs and speed to climb the hill. On the downside of the hill, the rig reaches much higher top speeds because of the same reduced wind drag. On the highway, 53% of the usable power you get from burning fuel is used to combat aerodynamic drag. Clean up that drag around your mudflaps, and you can gain as much as 0.5 MPG improvement in your highway fuel economy.

Trailer Skirts Have a Limited Influence on Wind Drag

admin — Sun, 28 Nov 2010 20:51:52 +0000

On the highway, trailer skirts still leave residual wind drag surrounding the rear trailer axle, and this reduces your fuel economy, especially in cross wind conditions. Note the blow back air pressure on the conventional trailer flaps in this photo. Skirts also make handling and controlling the trailer in high winds very difficult. If you must operate with skirts, swap out your traditional mudflaps with Eco-flaps and you will improve your fuel economy by another 2%. Handling will improve, as well.

Road Spray Is A Signature Of The Wind Drag Surrounding Your Trailer

admin — Wed, 24 Nov 2010 20:45:32 +0000

Wet weather provides a great opportunity to see the wind drag being generated at highway speeds by your rig. Spray is the result of standing water from the road surface being picked up and vaporized by turbulent air currents. The wind drag that creates this vapor is pulling down your highway fuel economy. High levels of spray around your vehicle mean you have some great opportunity to increase your fuel economy by reducing drag in all conditions, wet or dry. Even small changes that clean up air flow like Eco-flaps and Airtabs will greatly reduce this drag and the associated spray in inclement weather. Your fuel economy will improve significantly, as well. The trailer in the left photo is running with Eco-flaps while the trailer in the right photo is using conventional flaps. Both photos were taken a few minutes apart in the same light rain. Note the difference in spray.

Beware Clutter At The Rear Trailer Axle

admin — Fri, 26 Feb 2010 22:55:20 +0000

Trailer OEMs make design decisions favoring ease of assembly and maintenance access sometimes. Don’t let the position of hoses, air tanks and brake boxes at the bogey create additional wind drag for your trailer. Most of these components can be tucked up into the bogey frame itself, removing additional obstructions to oncoming air flow. This far back on a trailer, every item creating drag reduces MPGs significantly.

Consider Straight Mudflap Hanger Brackets for Trucks

admin — Mon, 29 Jun 2009 22:02:38 +0000

When you use angled hanger brackets for Class 8 truck flaps, you create the same effect for 30% or more of the flap that using stiffeners create. You restrict the top 1/3 of the mudflap from having any flexibility because it is anchored to the rigid angle design of the bracket. This is a critical area of wind drag on mudflaps at highway speeds, as the high speed jet of air that flows over the wheels and tires has significant impact on this upper portion of a solid mudflap. Consider changing over to straight brackets on the truck, and hanging those brackets slightly lower to clear any interference the angled brackets were designed to avoid.

Eliminate Steer Tire Mudflaps

admin — Mon, 29 Jun 2009 22:02:31 +0000

If you are putting high mileage on your rigs consistently week to week, you should look at removing steer tire flaps if you currently use them. No doubt they look good, and they help keep steps clear of mud and ice. These flaps however hang lower than anything else on the rig, catching the full force of oncoming air; and they represent another 2 square feet of surface area obstructing forward motion for the rig. Kenworth published information early in 2009 confirming that their steer tire flaps generate ½% reduction in fuel economy over the road. For a more aerodynamic profile, eliminate the use of steer tire flaps.

Remove Excess Flap Material

admin — Mon, 29 Jun 2009 22:02:16 +0000

If you substitute a longer mudflap for trailer use, and you recut mounting holes to cinch up the flap and shorten it to a more practical length, don’t forget to trim off the excess you create at the top of the flap. Once you remount the shortened flap, any material left above the hanger bar (3” to 4” typically) will drag serious wind in the path of the jet of air coming off the tires. Remember that correcting little things like this really adds up aerodynamically to improve fuel economy at highway speeds.

Increase Your Green Profile as a Fleet

admin — Fri, 22 May 2009 19:36:53 +0000

INCREASE YOUR SUSTAINABILITY/’GREEN PROFILE’ AS A FLEET. If you are an aspiring SmartWay partner, or are trying to meet certain sustainability or reduced emissions goals as a fleet, attacking the trailer mudflap wind drag issues is one of the fastest and cheapest ways to significantly reduce fuel usage.

Don’t Run With Extra Flaps

admin — Fri, 22 May 2009 19:36:18 +0000

DON’T RUN WITH EXTRA FLAPS. Tankers, in particular, have a tendency to use both truck flaps with front fender flaps on their tankers. One or the other will usually suffice. Operating with two extra flaps generates at least 1/3 more wind drag on the highway from the flaps. The same is true for flatbeds. If you don’t have to run with extra trailer flaps from a DOT standpoint, then don’t. The extra flaps cost another 2-3% reduction in overall fuel economy for the rig. If trucks have to bobtail at some point, and don’t usually run with flaps, store them securely like you do bad weather chains, behind the rear wall of the cab where they can be accessed and installed on the truck when required.

Eliminate Flap Stiffeners

admin — Fri, 22 May 2009 19:35:57 +0000

ELIMINATE ANY KIND OF FLAP STIFFENER. Mudflap wind drag costs enough fuel economy, don’t add insult to injury by trying to keep the flaps from blowing back at highway speeds. These stiffener accessories amplify the parachute effect of each flap, trapping just that much more wind and further reducing highway fuel economy.