The Bulletin file photoHigh-end bikes abound in Bend and are the target of recent thefts.

Those in the market to buy a mountain bike are faced with a dizzying array of choices these days.

New or used? Full-suspension or hard tail? Wheel size of 26 or 29 inches?

Wait, rephrase that last question: 27.5 or 29 inches?

Most in the industry agree the 26-inch wheel size for adult mountain bikes is essentially no more — it will soon go the way of cassette tapes and flip phones. The rise in popularity of 29-inch wheels over the past 10 years has eclipsed the old size, as has the recent addition of the 27.5-inch (also called 650b) wheel size.

“I think for all intents and purposes, on higher-end mountain bikes, it is dead,” Mike Schindler, co-owner of Sunnyside Sports in Bend, says of the 26-inch size.

It still makes sense as a wheel size for kids about 12 to 14 years old, Schindler notes, adding that Trek bicycles is keeping 26-inch wheels in its lower-end hard tails.

So, how does a mountain biker decide between 27.5 or 29?

To begin with, so-called “29ers” will be much easier to find for those who are looking for a used bike, as the 27.5 size just hit the market in the last couple of years.

Schindler explains that the 29-inch size is generally better for cross-country-style riding, as most World Cup cross-country racers are now riding 29-inch wheels. The 27.5 size is geared for more aggressive riding that includes jumps and technical trail features.

“It just comes down to, do you like to keep your wheels on the ground or do you like to jump?” Schindler asks. “Bigger wheels aren’t quite as much fun in the air, and the bikes are just not quite as agile.”

Mountain bikes with 29-inch wheels were introduced about 10 years ago, with the idea that the larger wheels could roll over and through challenging terrain (rocks, roots, sand, etc.) more easily because of the greater surface area, allowing riders to better maintain their momentum.

The problem was that some riders felt the bikes were not agile or responsive enough when turning through tight, twisty singletrack.

The 27.5-inch wheels were brought on by bike manufacturers to try to fill that gap.

Schindler says he considers Bend a “29er town.” The traditional singletrack west of Bend between Century Drive and Skyliners Road is suited best for a 29er, he notes. But the new Wanoga trail system, also located west of Bend but south of Century Drive and designed with more free-ride flavor, might be suited more for a 27.5-inch-wheel mountain bike.

“If you like a little more technical, jumpy terrain, then you might like the smaller wheel in some of those circumstances,” Schindler says.

The smaller wheel also fits better geometrically for the longer suspension of free-ride and downhill bikes.

All of this may seem confusing, and it gets even more so: 27.5-inch wheels are not actually 27.5 inches, according to Schindler.

“That infers that the wheel is right in between 26 and 29, which is inaccurate,” he says, adding that “650b is closer in size to a 26. The companies that are really going headlong in, and think they won’t have to carry 29ers much anymore, call it 27.5, because it’s easier for them to market it as a wheel size that’s perfectly in between.”

While most major mountain bike manufacturers are standing firmly behind the 29er while also offering 650b bikes, Giant Bicycles is going all in on the 27.5. The company is still making 29ers, but in quite limited numbers, according to Schindler.

Companies such as Trek and Specialized, he says, see the 29er as the more “go-to” wheel size.

“Different companies have different philosophies on where to stick the wheel size into their lineup,” Schindler says. “Having a company make three wheel sizes is not sustainable.”

Schindler says he does not foresee mountain bikers ditching their 29ers for the 650b size. He tries to keep things simple for customers.

“I frame it these days as, do you want small wheels or big wheels?” he says. “The small wheel just got a little bit bigger.”

— Reporter: 541-383-0318, mmorical@bendbulletin.com.