Review: Dahon Formula S18


This bike isn’t like most folding bikes. On first glance, it looks similar to the standard 20-inch-wheeled folder seen on the streets and public transportation in every city. Closer inspection reveals some standout features: disc brakes, high-end Schwalbe road tires, and an 18-speed drivetrain with gearing suited to spirited riding.

The ease with which the Formula folds—a trait of the highest importance—reflects well on Dahon’s three decades of folder manufacturing experience. Within a few attempts I had the Formula folded up in under a minute. A small magnetic clasp keeps the bike closed when carrying it, and when closed, it supports itself upright. High marks all around, particularly for the simple and sturdy metal folding pedals.

Dahon designed the Formula for riders “with tougher commutes that demand speed, portability and endurance.” Claiming to fit riders from 4-foot-8 to 6-foot-4, the handlebar and seat height adjust easily with quick-release levers. I found the handlebar height adjustment particularly useful—slide it up for comfort and a heads-up position for short trips, drop it down for more speed and leverage on longer rides. The frame has mounting points for a rack and fenders, and Dahon sells versions of each designed specifically for 20-inch wheels.

I packed this bike as luggage for a February trip to Minneapolis, where I managed to put about 100 miles on it in four days, including commuting to and from the airport. I didn’t expect to ride it so far, so I was pleasantly surprised by how well the Formula handled 15-20 mile rides, a distance often outside what most riders tackle on folders. The tall gearing allowed for a brisk pace, and the small wheels accelerated with authority, but they would quickly lose momentum if I slacked off at the pedals.

The Forumla was a great little city runabout. I found the handling to be quick, but incredibly well-mannered. The high-quality brakes and tires provided a level of control and handling I didn’t expect from a small-wheeled bike. When speeds got up into the high 20’s I needed to keep a steady hand on the bars, as things could get a little nervous, but after a few rides I was at home on the Formula. In extreme conditions, such as traversing icy bike paths or a few hundred yards of XC ski trail, I expected squirreliness, but this little folder never seemed to get upset. The Schwalbe tires deserve a lot of credit here—they performed much better than a slick tire should in low-traction conditions.

The Avid BB5 disc brakes provided all-conditions stopping power, but proved to be more finicky to set up drag-free than their more expensive sibling, the BB7. The Microshift shifters are not a well-known brand, but they did their job with no complaint. Both the saddle and grips worked well, even on longer rides without gloves or padded shorts.

The only real oddness with this bike is the oversized front chainrings. The small wheels need bigger gearing to equal that of a standard-size road bike. While the 56/46-tooth crank shifted well, don’t expect to find replacements in stock at your local bike shop.

I’m happy to say Dahon managed to create a folder that meets all their design intentions. This is a handy little bike, but don’t let its pedestrian appearance fool you—it has the heart of a racing machine.

Vital stats

  • Price: $1,400
  • Weight: 24.5 pounds



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