Build it and they won’t necessarily come.

Imagine, if you will, some of North America’s best cycling infrastructure, including separated lanes, plus a civic government determined to make your metropolis a haven for pedal-powered commutes, no matter what the cost.

And finally, imagine nearly perfect weather for cycling: not too hot, not too cold, and snow so rare a couple of inches worth is front page news.

You’d have to be crazy to drive a car to work in such ideal conditions — and yet in Portland, Ore., a city consistently ranked the most bicycle-friendly in North America, cycling is hitting a wall.

Technically, Portland reached that wall in 2008, when the number of commuters riding downtown plateaued at just over 6% — but the city kept spending anyway.

Despite new and better cycle lanes, the number of work-day peddlers remained stagnant after ’08, even dipping slightly, while the number of cars stayed the same.

Stagnation, in the face of a landmark 2010 decision to invest $613 million into bicycle commuting, in hopes of increasing that ratio to 25% by 2030.

Six years later, the number of cyclists remains the same, and Portland is finally saying enough.

According to bikeportland.org, cycling’s most admired city has finally hit the brakes on spending, having slashed the budget for neighbourhood greenway bike lanes, a priority of that 2010 cycle strategy.

After two decades of free-wheeling finances, it seems even Portland has realized there’s only so much spending you can do for a fixed minority of commuters — and with the Oregon city in the midst of a financial rough patch, infrastructure that benefits only 6% of citizens was first to go.

It’s a cautionary tale for Calgary, as city council here considers a network of segregated bicycle lanes for downtown Calgary — the theory being that hordes of Calgary commuters are itching to cycle, once the lanes are built.

Portland is proving that theory is at least partially wrong.

“That point is very valid, because the same thing happened to Vancouver after they spent additional millions, and the increase in cyclists was minimal,” said Coun. Ward Sutherland.

“My concern is the original research for the city core, it was based upon a specific demographic of hardcore cyclists, not the average person — and it’s like, if we make everything perfect for the hardcore cyclist, everyone else will want to ride, too.

“But I don’t think that’s the case. When it’s -5C and the weather’s bad, it doesn’t stop hardcore riders, but there are plenty of people it does.”

It’s true that Portland’s experience has been mirrored in Vancouver, another city with a climate well-suited to cycling and a budget to match.

The most recent Statistics Canada data shows that bike commuting in the Metro Vancouver region inched to 1.8% in 2011, from 1.7% in 2006, while in Vancouver proper, bike commuting went from 2.9% in 2008 to 3.8% in 2011.

As well, a study of separated Vancouver bike lanes published in kitsilano.ca last fall shows almost no increase in use since 2009 when they first opened.

What both cities found is that the initial investment in bike infrastructure does attract new riders, but the point of diminishing return is quickly reached — and according to an 2013 City of Calgary report, Calgary is already approaching 4.7%, as measured on a May weekday.

When vaunted Portland can only attract 6% of commuters to cycling after building the best bike network in North America, can Calgary really do better?

It’s why Sutherland says Calgary should go slow in spending more money on Calgary’s bike infrastructure — when a single separated downtown bike lane costs up to $3.7 million, finding out how many extra people really use them is a prudent move.

“We need to have a nice progression, and to have a trial first,” said Sutherland, who’s pushing a motion seeking a study on commuter cycling city-wide, not just the core.

On Monday, council will have a chance to revisit the contentious bike lane on the east side of 1 St. S.E., which has been rejected by committee — and where even Mayor Naheed Nenshi wants temporary barriers to first test the appetite of Calgarians.

Bike commuting is here to stay in Calgary, but Portland’s expensive lesson is one this council should heed: You can’t buy a bicycle culture.