Skip to main content

See also:

Bike flags a big drag, says Harley

Zien aboard his Trike
Zien aboard his Trike
Journal Sentinel, Rick Barrett via Facebook, Motorcyclist Magazine

Think your big Hog with all its horsepower and modern engineered parts can handle an extra load from bike flags? Harley says no, according to a story in the Milwaukee, Wisconsin Journal Sentinel. Dave Zien, a life-long Harley enthusiast who logged more than a million miles on his '91 Harley (now preserved at the Sturgis Motorcycle Museum and Hall of Fame) took his '14 Harley trike into the dealer when the clutch failed. The motorcycle, being under factory warrantee and with only 15,000 miles on the clock, Zien figured it'd be covered. The MoCo however, ended up denying his warrantee claim, stating that the flags caused the problem.

According to the story, Harley spokeswoman Maripat Blankenheim stated that the flags put a "terrific drag" on the motorcycle and the motorcycle was not designed to handle the added resistance at high speeds. She also said that the flag mounts are not "Harley products." According to the story, she added "when you alter a motorcycle with noncompliant products, that does impact your ability to make a warranty claim."

Needless to say, this story has stirred quite a ruckus among Harley enthusiasts, who likewise sport flags on their machines. Zien, a retired state legislator and Marine Corps veteran says he won't let them take his flags. Other people cited in the story likewise feel upset about Harley's decision. Regardless of how you feel about the company, or flying flags, the question which hasn't been asked yet is, where's the science to back up Harley's claim?

An internet search of flag wind resistance finds one particular study found on the Embassy Flag website, where it shows various wind loads at a calculated stress factor upon a regular ground-fixed flagpole of 39.3 feet in length. The chart is a bit confusing but basically, one can extrapolate that a small flag profile (smaller square footage of flag) at a higher height is less drag than a larger flag. Ok, that's a no-brainer. But at that higher height, with a smaller flag (8' x 10') the corresponding pressure in Nm (Newton Meters converted to ft lbs) isn't all that great with a wind speed way faster than virtually any Harley trike can travel. Perhaps as low as around 108 ft lbs of pressure on that flag pole at given height.

Yes, that's a single flag on a pole and the article cites Zien had up to seven flags on his bike. But his flags are only 3' x 5' and sure aren't up in Green Giant territory.

So yea, sure, it's not the same, but it gives a decent idea that perhaps Harley is citing some voo-doo science. Or, maybe they just don't want to honor their warrantee and they'll use any excuse to do just that.

Another question not yet asked: what about all the Harley folks on both bikes and trikes that tow trailers? Figure a trailer can likely hold a couple hundred pounds of weight. Certainly, it's not exactly the same, a trailer being a fixed weight that only changes with attitude (more weight uphill, less downhill) and flags can vary the resistance load depending upon the speed of the bike. But how fast was Zien going? According to the study cited above, not more than 80. According to the study, no flag will sustain winds of 80 mph because at that speed, flags are torn off the poles.

Hmmmm... so if that is true and Zien's flags aren't exactly of the highest quality in regards to fixation to the pole, how's his flags staying put at highway speeds? Harley says, the flags have tremendous drag at those speeds.

Take a look at the picture in the article. Zien's flags are clearly not in clean air. In other words, the motorcycle batwing fairing, windshield, overall width of the machine and of course, Zien himself, clearly deflect a lot of wind away from the flag itself.

There's more questions than answers here, that's for sure. The main question must be, where does Harley get their science from? Can they prove scientifically that toting a few flags at say, 60 mph, is any more drag than loading up with luggage and piling on a rather portly passenger? We've all scene folks on trike's riding two-up who are almost spilling off the thing. That doesn't add stress to the drivetrain? What's next, denial of drivetrain warrantee claims because the owner gained weight since purchase and hooked up with a heavier set companion? Yea, right.

And, what of Harley's statement that the flag mounts aren't Harley products? So, if Zien was using Harley flag mounts, the wind resistance would have been warded off by some sort of magical force field? Seriously.

Harley needs to rethink this. Fix the bike under warrantee for this dedicated, devoted Harley enthusiest and then, do the science to back up their claim. Just saying flags which are not Harley accessories void the warrantee is ridiculous.