Having become acquainted with the tiny but mighty Zero FX, and struggled through a thorough technology briefing at the Zero factory, it was time to try the "base models" of the 2015 Zero range. The Zero S (streetbike) and Zero DS (dual sport) both share the same platform in terms of frame, motor and the giant monolith battery pack. And despite the fact that they're significantly down on power and torque compared to the high-performance Zero SR, this pair of electrics offer a surprisingly good time.

The monolith is a non-removable block of battery that sits where you'd normally find the engine on an internal combustion bike, and for both the S and DS you can specify a 9.4 or 12.5 kWh battery capacity for it. On top of that, you can add a 2.8 kWh "power tank" module that slots in where the fuel tank would normally sit, bringing the total possible battery configuration of the S and DS bikes up to 15.3 kWh.

That's a serious amount of energy to have between your legs. For comparison, Gizmag's esteemed editor Noel McKeegan lives in a solar-powered house that's completely off the grid, and he runs his entire home with about 20 kWh of battery storage. Depending on your battery choices, the S and DS go for between US$13,345 and US$17,840.

Both bikes make a maximum 54 hp (40 kW) and 68 lb-ft (92 Nm) of torque and they weigh between 171 and 204 kg (377 and 450 lb) depending on how much battery you're carrying. They're a little soft off the line, being geared for a 95 mph (153 km/h) top speed, but once you're moving you've got access to plenty of acceleration at all speeds, and you rarely find yourself wanting on a corner exit.

As with all Zeros, the S and DS are now equipped with Bosch ABS, which is a reliable and generally unintrusive platform. The new Spanish J-Juan brake system gives more than enough stopping power to stand the bikes on their noses, even with just a single disc. Mind you, it's not an extreme performance braking system, it's a good, reliable street system.

Probably the biggest upgrade for 2015 is the custom-tailored Showa suspension, which is fully adjustable and built to suit the needs of each model. In our day's worth of road riding, the suspension handled a variety of surfaces well, and also responded nicely to adjustment.

Where the S and DS differ is in their tires, ride height and riding ergonomics. The S gets Pirelli Sport Demons, a friendly 807 mm seat height and a compact riding position with narrow bars and mirrors, perfect for splitting traffic around town. The DS gets MT-60 dual sport tires, a considerably taller 843 mm seat height, and wide, flat bars that let you stand up to ride the rough stuff, and also give it a much more muscular and aggressive riding posture. The DS ergonomics give it the feel of a narrower waist, even if the seat's the same for both models, and as a 5 ft 11 in big fella, the DS felt fantastic to me where the S felt perhaps a touch cramped.

We took the S and DS bikes for a morning's ride through the redwood forests around Santa Cruz, all the way up to the famous Alice's restaurant on Skyline overlooking the San Francisco Bay. In terms of handling, the road advantage goes to the S. Its road profile tires and 17-in front wheel steer quickly and precisely. The DS's wider bars make up for the extra gyroscopic weight of its 19-in front wheel, so it still turns well, but its chunkier dual sport tires don't give you the same confidence as you lean the thing over.

One thing I ran into as the pace came up a touch was the thermal warning light. Our test was on a warm day, and I was doing my best to abuse the bikes in true motorcycle tester style. Feeling a little constrained by the group pace, I was hanging back off the tail end of the group, then going absolutely banzai to catch up – rinse and repeat. I'm not good at riding below my natural "fun" pace – I get frustrated, my mind wanders, and I feel like that's when bad things start happening.

So at one point playing catchup on the S, I felt the peak power drop off by a good 15-20 percent. The Zeros have a thermal management system in place to protect both the battery and the motor from overheating. It warns you by flashing a light, before eventually cutting the power to a level that can be sustained without incurring thermal damage. It happened to me and to one of the other riders, but only once each, and full power came back after a few minutes at a more relaxed pace.

Range, fully loaded with the large battery and the Power Tank, is a whopping 185 miles (298 km) on the S, and 170 miles (274 km) on the DS at city speeds. The disparity can probably be put down to a larger frontal profile on the DS, as well as the fact that the broader riding position likely makes the rider a bit more of a windsock too, especially if (like me) they've been hitting the Mexican food a bit too much.

Probably the biggest surprise for me was that the S and DS were almost as much fun as the mighty SR in the twisties. They're definitely more sluggish off the line, but once you're moving they're surprisingly sprightly out of corners.

It should be noted, we didn't really interface with the charging side of any of these bikes, because as soon as we reached Alice's, with battery levels starting to run down, the Zero team unloaded a fresh truck of SRs for the ride home. Still, both bikes left a very positive impression and are certainly light years ahead of the 2011 model S we rode a few years back.

Enjoy our full fleet test video of the 2015 Zero FX, S, DS and SR below. Also check out our 2015 Zero FX review here, and learn more about the Zero factory and battery technology here.

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