Folks can't seem to get enough of those Heelys shoes with retractable skating wheels. Kids with grazed knees dig it. Now their parents can, too. The company went public this morning after pricing its initial public offering at $21 a pop. Like its signature shoes, the stock is on a roll. Heelys (NASDAQ:HLYS) opened well above its serving suggestion at $30.30 this morning, trading as high as $38.75.

Demand was obvious, even before this morning's first trade. In last month's filing with the SEC, Heelys was looking to place 6.25 million shares -- half of them being sold by insiders -- between $16 and $18 a share. At the time, I figured that the company was being priced too cheap.

Over the past four quarters, the company has generated $19.1 million in trailing net income. With 23.9 million shares outstanding after this morning's offering, the $21 price had the company trading at just 26 times earnings. A strong holiday showing could drop that trailing multiple into the low 20s. But of course, you won't be buying in at $21. At $35 a pop, investors are now paying more than 40 times trailing earnings. Is that still a good deal?

After all, what if wheeled footwear proves to be a passing fad? That would be devastating for Heelys, since it's generated 99% of its sales through the first nine months of the year from its signature rolling shoes. However, the company's amazing growth over the past two years makes this a risk worth taking, should the share price come down over the next few weeks.

Sales at Heelys more than than doubled last year, to $44 million. If that isn't fast enough for you, snap out those wheels and check out the 303% top-line spurt at Heelys through the first nine months of this year. The bottom line has been even sweeter, soaring more than 500% this year.

Yes, footwear can be exciting. Crocs (NASDAQ:CROX) and its eclectic-yet-cozy original shoes produced a successful IPO earlier this year. Under Armour (NASDAQ:UARM) is better known for its athletic apparel than its new line of pro cleats, yet it too has had a great run since going public 13 months ago.

We also have Nike (NYSE:NKE), of course. The "swoosh" star may seem like a slow-moving behemoth these days, but in Nike you have a stock that has been a 20-bagger over the past 17 years.

Naturally, Heelys hasn't earned the right to even be mentioned in the same sentence as Nike. If its shoes become the next wave of pocket bikes or Razor scooters, the current heady growth will crash and burn sooner rather than later. However, what if this is only the beginning? There are still plenty of retailers yet to stock the shoes, and the company is generating just 16% of its sales outside the United States. Keep watching the trends. In a few years, Heelys is bound to be either a Wall Street superstar or a complete dud. There's no middle ground here. Up or down, Heelys will be a mover. Then again, maybe that's what the wheels are for.

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Longtime Fool contributor Rick Munarriz has never been much of a skater. He does not own shares in any of the companies in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.