Aero mod gains below 55 mph?
 

95% of my driving is at 55 mph or less.
Would I see any gains for aero mods?

I did to a lower grill block a while ago and saw minor improvements but that didn't cost me anything.

Debating on pizza pan hubcaps and rear wheel skirts but I don't want to drop $50 plus the time to make it if I am only going to end up seeing a 0.5 mpg improvement.

I have looked at other threads with peoples A-B-A runs and some show gains of 1.5 - 2.5 mph while others are only claiming very slight improvements at 55mph.

Opinions?

Everyone has them, and they all stink. You should install some wheel skirts. If your wheels have an awful, air-churning design, cover those too.

A Metro spends half of its energy overcoming drag at a 30mph steady state cruise: Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com

So while drag reduction is less important at lower speeds, it still plays a role. In some cars, it's a larger role than in others.

Sure you would.

Even the Insight that I drive has a least 50% of it's air drag at 55 mph, so any improvements help.

It all adds up, so the more people who consider ecomodding, the better!!

Jim.

I've seen improvements from my upper grille block down to say 40-42 mph .


(I have no baseline data for long stretches of road with lower posted limits, as there are no such roads in my area.)

I ran some nice skirts for a year and couldn't detect any fe savings there might have been.

35-40mph is the cutoff for many cars. The worse a car is, the lower the speed threshold. Also, colder temperatures make aero drag more important.

At a given speed, the aero mods have more impact if you decrease the rolling resistance. Pump up your tires to max sidewall, or more if they are already there, and have fun at aeromodding your car ;)

My commute is under 90km/h (56mph), I generally Pulse & Glide at 85-70km/h (53-43mph). Even at these speeds I can feel when the rear wheel skirts are present or not. Some other aeromods permit me to make the car to accelerate on small downhills while it was decelerating without it.

I pumped up my tires lately to 4.0bar (58psi) from the 3.5bar (51psi = max sidewall) where they were during last year, and I found a couple places on my daily commute where Pulsing up to 56mph instead of 53mph permits me to skip the next Pulse :)

Have fun,

Denis.

I A-B-A tested my rear wheel skirts + Kammy and got a 7% improvement @ 70 km/h (44mph) and 8% @ 100 km/h (62mph). I'm willing to bet that you'd see at least 5% @ 55mph, maybe even 10%.

It took me almost half a year to get used to the new coasting distances at city speeds (up to 60 km/h, 37mph). Almost rear ended someone in the beginning.

People sometimes tell me that my mods don't help in the city, because there isn't enough air drag at 50-60 km/h. I answer by asking how long they can keep up 40 km/h on a bicycle. Not too long? I wonder why...