Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/1166337
2019 ZERO SR/F F I R ST R I D E R E V I E W P92 THE POLITICS OF REGEN The most noticeable difference between sport and street modes is how the regenerative brak- ing is triggered when you roll off the throttle. In sport mode, the regen doesn't kick in until the throttle's just a few degrees from fully closed. This permits a more precise regen application and allows you to get back on the throttle harder. In street mode, proportional regen takes over several degrees on the twistgrip away from having the throttle completely closed, and as the grip gets closer to the full off posi- tion, the regen increases, albeit progressively, delivering what amounts to engine braking which the rider can modulate as the situ- ation requires. The only trade-off is that when rolling on the throttle again, the initial acceleration isn't as snappy. However, I found that de- scending a twisty hillside road in sport mode, it was hard to keep up the flow because the regen kept slowing the bike quite abruptly as I closed the throttle for a turn. Okay, you say, adjust the regen—but the only way to do this on the Zero is to get on your cellphone and do it through the app. That's impractical! I want to be able to alter it quickly and easily now via a switch on the bar, just as I can on BMW's C evolution E-maxi scooter, and I think Askenazi & Co.—who W rapped around the battery pack, which it uses as a fully-stressed component, is a triangulat- ed tubular steel spaceframe worthy of any Ducati, bolted to cast-aluminum plates which each comprise the outer housing of the twin-sided swingarm. This is made from two halves of pressed steel welded together to form an ultra-sturdy structure – that massive hit of torque delivered by the new Zero motor all through the rev range was too much for an aluminum structure to support, says Askenazi. That's why the swingarm pivots on a 100mm diameter oil- impregnated sintered bronze plain bearing, to tie everything in tight to create a massively solid integrated swingarm pivot which encircles the motor's drive shaft in a coaxial arrangement which none other than Massimo Tamburini pioneered on his first-generation Bimota designs, and for the same reason – constant chain tension for him, and a con- stant drive belt tension on the SR/F. Termed the Power Pivot by Zero, this coaxial format permits a very high belt tension to eliminate any drivetrain lash, as well as to promote long belt life. The fully adjustable cantilever Showa shock sits offset to the right and delivers 140mm of travel to the cast alumi- num rear wheel. Its 5.50-inch rim carries a 180/55-17 Pirelli Diablo Rossi III tire that's far larger than anything Zero has used before—last year's SR range-topper carried a 130/80-17 Pirelli MT-01 on its 3.50- inch rear wheel. It's the same up front, where the 43mm Big Piston Showa SFF fork, which is again fully adjustable with 120mm of travel, carries a 120/70-17 Diablo Rosso III on a 3.50-inch wheel, where last year the SR had a 3.00-inch front rim and a 110/70-17 tire. Brakes are provided by J.Juan, with their front four-piston calipers doubled up and radially mounted via special Showa fork lowers produced exclusively for Zero, and bite up- sized 320mm floating discs, with a 240mm rear disc and single-piston floating caliper. The need for the uprated brake package is evident when you check out the SR/F's claimed weight: 485 pounds for the standard SR/F, and 498 pounds for the Premium, with its bigger char- ger. This is a lot heavier than the outgoing 2018 SR with the same battery and charger at 414 pounds, thanks to the upscale brakes, suspension, tires/wheels and other chassis hardware. There's indeed a weight differential between the Zero SR/F and comparable rival I.C.E streetfighters like the 461-pound Ducati Monster 1200—but the American E-Rod more than makes up for that in how it delivers its performance, thanks to its huge 140 lb-ft dose of constant torque, com- pared to the Ducati's 87 lb-ft that's positively wimpish by comparison. THE FRAME