Dahon Formula S18
At $1399, the Dahon Formula S18 is designed for folding bike riders who want more than just convenience—they want performance. This is most clearly illustrated by the inclusion of Avid BB5 disc brakes. Along with its color matched Schwalbe tires the bike simply looks more serious than some of the other folding bikes out there.
The one size fits all frame is made from 7005 aluminum alloy, which is stiffer and lighter than 6000-series alloy, and of course more expensive. Though it’s hard to imagine that the same frame can suit such a wide range, Dahon claims that the Formula S18 is designed for riders between 4’8” and 6’4” (though not over 230 lbs).
There is a massive amount of adjustability afforded by the 580 mm seatpost. Really short riders may actually need to cut the stock seatpost down in order to get the seat low enough. The bike features a telescoping “handlepost” that allows you to tailor the handlebar height via quick release. This is a good place to mention that the lack of a traditional stem makes the steering feel quite unique. The bike’s geometry is tuned so that the bike is stable, even at speed, but to me it just feels a little twitchy, especially when I need to stand up and climb.
It’s interesting to think about how 20” wheels effect the performance of a bike. With a 56/46 crankset and an 11-25 9-speed cassette, you’ve certainly got the gearing to get up to speed (26-95 gear inches, to be exact). But what I seem to notice is that the small wheels are pretty ineffective at smoothing out road vibrations. Pebbles, broken concrete, manholes and the like all seem like significantly larger obstacles than on a 700c equipped bike. More than anything, the “feel” of 20” wheels limits my willingness to go really fast. I should note that some popular folding bikes use 16” wheels, so maybe I should count my blessings.
All in all, the bike is rather fun to ride. It accelerates quickly and the disc brakes make it stop on a dime. The frame feels solid enough to forget that your entire bike is designed to quickly fold in half. The aforementioned handlepost assembly does occasionally creak, but not so much in a disconcerting way, just enough to remind you that it’s probably not a good idea to wheelie drop any tall curbs.
The Formula S18 weighs in at roughly 26 lbs, which isn’t exactly light, even for a fully geared city bike. But when it’s folded it feels lighter than it actually is. Folding the bike is an absolute breeze, and the folding pedals and magnetic tabs that hold it closed are just plain cool, in my humble opinion. When folded the bike measures 11.3” x 31.2” x 25.7”. While not the most compact folding bike on the market, it’s still plenty versatile.
Looking around the bike there are an equal number of house brand and name brand parts, all of which seem to be on par with what you should expect from a bike at this price point. I know from years of personal experience that WTB makes quality rims, and Shimano’s Tiagra drivetrain components are built to last. Dahon’s house-brand cockpit components are comfortable and durable enough to get you get from point A to point B quickly and safely. www.dahon.com