I don't know about the Helkama Jim, but I've already remarked on the weight of the Gazelle
It weighs 28.6 kilos including a 2.1 kilo battery, while the original Panasonic motored Twist weighed 22 kilos including a 3.7 kilo battery, the later versions a little more.
Taking into account it's battery is 1.6 kilos lighter, the Gazelle bike alone manages to be an extraordinary 8.2 kilos / 18 lbs heavier than the Twist. There are a few complete bicycles that total this weight difference. Perhaps Wildebeest would have been a better choice of name!
This does appear to impair it's hill climb abilities in that it wastes the additional power that it's latest model Panasonic power unit has, and some more. It can still climb virtually anything regardless, but the loss due to that extra weight is shown in slowness of climb.
It may be that the Helkama is lighter, or that it's producers have opted for more power and less range in their specification for the unit's supplied. The original Panasonic unit came with power limited according to Japanese law, but this later unit is more powerful and Panasonic may let producers specify the level.
And of course much depends on how much the Extra Energy site is to be trusted, some are very critical of it.
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