EIMEI NJS (57 cm) - Japanese steel

Dec 15, 2025 Svante Oxblod

Fixed-gear hub from Japan’s Keirin league

The simplest bike is often the most beautiful. NJS frames are custom-made to measure and brazed to perfection from thin-walled tubing with beautiful lugs for optimal stiffness.

Most Keirin frames you find online have been used and crashed by their original owners. When that happens, they’re no longer allowed to race them, so they’re sold to us enthusiasts. This example had no dents or structural issues, just a few paint chips. A great candidate for a high-end fixed-gear bike for street use.

It was hard to find a better-colored backdrop for the photoshoot. It’s fun when that happens! A bike like this consists only of the components absolutely necessary for riding, making it both efficient and good-looking. We built the wheels in our workshop to be indestructible. We settled on DT Swiss XR 331 rims, which are rated for tough mountain biking. You might say that’s unnecessarily tough, but they weigh only 380 g, giving us a fantastic strength-to-weight ratio. The rim is made for disc brakes, and the fork isn’t drilled for a rim brake, so for two reasons, you can’t install a front brake on the bike. Note that you’re required to have one by Swedish law if you ride outside the velodrome.

A fairly large chainring with 53 teeth. Our general advice for a fixed-gear hub in Stockholm is 48x17 or 47x17 if you want to experiment with different rear sprockets and get plenty of “skid patches.” This bike’s gear ratio is 53x19T, which is similar to the recommendations above. The advantage is of course the visual impact; a larger chainring looks cool. But with a larger rear sprocket, you get a more efficient chain that loses less energy through tight bends. Though you really only need to consider that if you race on the track.

As mentioned above, the fork crown has no hole for a front brake. There’s an estimated 3 mm of clearance between the tire and the fork (the camera angle exaggerates it a little). NJS bikes rarely have tires wider than 23 mm for racing, but that’s too narrow and impractical for city riding. We didn’t want to build a complete NJS-stamped bike, even though we respect those who do; we wanted a few practical choices, such as clincher tires and clipless pedals from Time, of course. The DT Swiss rims have an internal width of 20 mm, and the 4-season tires labeled 25 mm on the packaging swelled to almost 28 mm after a day at maximum pressure. Luckily, they fit both front and rear, so the rider doesn’t have to bounce around at 120+ psi.

Drop handlebars, preferably a model specifically designed for track cycling, are really the only right choice for an NJS bike. Without brake levers to rest your hands on, however, these handlebars are unfortunately impractical and uncomfortable, as the neutral position is in the drops. That's why we went with a flat Bar with a suitable 65 cm width. If you brake/skid a lot, you get much better leverage and control over the bike with a wider MTB-style handlebar. It's not just an aesthetic trend we've seen in recent years; it also has definite practical advantages. It's so easy to switch handlebar setups on this type of bike that we encourage you to try many variations.

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