Lumen bike looks black in the daylight, but reflects white at night
By Paul Ridden
March 21, 2014
Pimping your person and your ride with reflective materials, bright lighting or glow-in-the-dark paint jobs to be as visible as possible to motorists at night can mean the difference between getting home safely or saying hello to a world of pain ... or worse. Inspired by passing highly-reflective street signs during daily rides and wondering why such technology couldn't be applied directly to bikes, the folks at San Francisco's Mission Bicycle Company have developed Lumen. During daylight hours, the city bike looks pretty much like any other, but when night draws in, light from car headlights hitting the city bike's retro-reflective frame and wheel rims is returned directly back to its source.
Light hitting the powder-coated frame and wheel rims of the Lumen Retro-Reflective City Bicycle doesn't just scatter off in different directions or bounce away at sharp angles, it is returned to its source courtesy of tens of thousands of tiny spheres. This effectively means that by day, there's just a slight sheen to an otherwise black or silver finish, and, since it doesn't glow in the dark, even pedestrians looking at the bike after dark won't see the bright Tron-like effect unless they shine a light in the rider's direction.
"Frankly, in an urban environment, the glow from glow-in-the-dark paint is barely visible," says Mission General Manager Jefferson McCarley. "It's a pretty faint glow for riding on city streets that are often already fairly well lit. It's just not that bright. When light strikes the surface of the Lumen frame, it's hard to miss."
"The thing that I like about frames that have been coated with a conventional glow-in-the-dark liquid paint is that they are visible to everyone: the rider, pedestrians on the street, and the driver of any combustion engine vehicle," he continues. "That's pretty cool. But I also think that it's cool that when I'm riding my Lumen (I ride one of the prototypes daily/nightly), everyone else sees a black bike. Day or night. It's a sexy dark gray color that looks great. It's possible that the only one that sees the magical effect is the person behind a steering wheel. Or anyone that takes a photo of my bike with the flash on. Some people like the way that greenish-yellowish glow-in-the-dark liquid paint looks during the day. It's not for everyone. Some of us prefer the understated, stealth look of a dark gray frame that is a lot more visible to motorists than frame painted with a conventional black paint."
A number of Lumen prototypes have now been powder-coated with a technology developed and patented by Halo Coatings. Any light entering the numerous tiny glass beads in the unique finish is returned back to its source, an effect that's said to be visible up to 1,000 ft (300 m) away.
"Picture a deer caught in headlights," begins McCarley when asked to explain how the retro-reflective effects works. "It's quite possible that all you see are two glowing eyes in the darkness in front of you. Here's how that works: when light enters a translucent object, in this case the eyeball of a deer, it goes all the way though to the back of the sphere and reflects back towards the source of the light. So our frame is covered with tens of thousands of microscopic deer eyes. OK, they are synthetic. No deer were harmed in the making of the Lumen."
To take the Lumen into the consumer space, Mission has headed to Kickstarter. Three models are being offered, with each frame being hand-built using hand-welded 4130 double-butted chromoly steel and available in five different frame sizes. "All the Lumen bikes featured are built with 700c wheels," reveals the company's Kai McMurtry. "With the one exception of 650c wheels for our shorter riders, all Mission Bicycles utilize 700c wheels and caliper brakes."
For a pledge of US$499, a single-speed, internally-geared Lumen frame and a fork will be shipped out to backers assuming the crowdfunding campaign is successful. Riders will then be able to assemble the rest of the bike to their own tastes and budgets. The first fully-assembled Lumen bike on offer is the 19 lb (8.6 kg) single-speed Lumen 1 in black for $1,245, and comes with bullhorn handlebars, a Valencia frame, Velocity Deep V rims and front caliper brake.
The 24 lb (10.9 kg) Lumen 8, with Shimano Nexus 8-speed internal hub and twist grip shifter, will be produced in silver at a pledge level of $1,595, and features upright riser handlebars, cables fed through a Sutro frame, brakes front and rear and Velocity Deep V rims. The top dog in the Mission kennel is the 25 lb (11.3 kg) Lumen 8SE for $2,500, an 8-speed special edition that includes a Shimano Alfine hub with trigger shifter, hand-made Continental Grand Prix Classic tires and a Sugino crankset that's described as indestructible and polished to a mirror finish. This model also sports a Sutro frame with internal cabling, Velocity Deep V rims and front and rear brakes.
If all goes as planned, shipping is estimated to begin in July.
"I can say now that I'm confident we'll reach our fundraising goal, and the Lumen retro-reflective coating will be available as an upgrade on any Mission bicycle after the campaign ends," says McMurtry. "At this point, we're not yet sure what the post-Kickstarter upgrade cost will be."
The campaign pitch video is below.