gearing

[gray198]

went and had a look around a new bikeshop today, where they had a good selection, including electric (la pierre or something like that ). Anyway looking at the bikes I was surprised to see that most of the more expensive ones just had a single chainring at front which was very small but a lot of cogs at the back. Is this the new way?. When I last bought a normal bike it seemed to be a triple chainring was thw thing to have.Yimes and technology change I suppose. Would this configuration suit a hub drive

 

[D8ve]

you don't need lots of gears on an ebike. The motor assist helps you climb serious hills without the serious stress you would have had.
The jury is out on small front rings. I think they are not good as reduce the top speed. But for mountain bikes perhaps not such an issue as 20 is plenty until gravity come in.
Some have an internal gear system spinning the front ring at 2.5 times crank speed. Again I don't like extra gearing and complexity.
But for a mountain bike a smaller ring means better ground clearance and straighter chain line.

 

[anotherkiwi]

On the road I moved from 42 to 48 on a 26" wheel bike it is night and day I feel much better. Your preferred cadence is another factor to take into account.

A single chainring and 11-32 or 11-34 should do the trick. Front chainring size dependant on whether you ride off-road and need climbing power or on-road and need speed on the flat and downhill.

Around here a double chainring - 48/50 - 38/34 and 11-28 will work better because some of the hills further south are "quite steep".

I am surprised that no yet offers e-bike specific ratios except pinion.