In this comment it's suggested that the Zero S is really a "learning bike" which made me think of the race results with the Zero S in the TTXGP
In the North American TTXGP there's an experiment going on using Zero S's as a precursor to a "spec class". It's called eSuperStock, and is only open to electric motorcycles manufactured in volumes over 25 bikes. If you think about the range of available electric motorcycles, only the Zero S/DS qualify. er.. it just occurred to me, the Native GPR-S might also qualify. In any case eSuperStock is being done as a collaboration with Zero Motorcycles, and they have done light modifications to four Zero S's to comply with the TTXGP rules.
That means the bikes are still limited to 88 miles/hr top speed.
In the TTXGP we've always had a huge gap between the top bikes and bottom bikes. As a practical matter not many teams can afford to build a bike that can compete with MotoCzysz, or Lightning, or Brammo's Empulse RR.
With the eSuperStock guys in the race the performance gap has been even more obvious.
This last weekend they did one interesting thing ... a couple Zero bikes were gridded with Ninja 250's in a gas bike race. The Zero bikes stayed together the whole time (they're closely matched in performance) but the two of them, lap after lap, fell farther and farther behind the 250's. It wasn't a matter of inexperience, because all the riders in the Zero eSuperStock team were experienced racers.
Which says - the Zero S performance is slightly less than the 250's