Chassis alterations come with the Ninja 300’s newfound, if petite, brutishness. According to Kawasaki, the reworked double-cradle, steel-tube frame uses main tubes 150 percent stronger than before; the top tubes are farther apart under the fuel tank and benefit from additional gusseting. This stronger frame no longer needs as much support from the engine as a stressed member, so the front mounts are now rubber isolated. While Kawasaki had the frame jigs apart, it reset the non-detachable subframe’s angle to help maintain a low seat height. While the wheelbase spec is slightly longer than the 250’s, it’s not because of frame or swingarm changes. Instead, the rear sprocket has three fewer teeth, so the axle rides further back in the adjuster channel. New wheel designs are used, while the rear hoop is a half-inch wider to accommodate a 140mm-wide tire. Finally, grownup rubber for the littlest Ninja. Well, mostly; the 300 rides on IRC bias-ply tires that, to everyone’s surprise, limit the bike’s handling not at all.