too much torque

[Artstu]

Better a few more teeth on the front then than a few less on the back?

I'd imagine your top gear is as small as you can go anyway.

I've been trying to find a close-up of the chainset to see if it's riveted, but have drawn a blank. Is chainring riveted or bolted on?

 

[RobF]

As Stu says, the cassette probably has the smallest possible ring already which is usually 11, although I think there are a couple of 10s at the higher end of cassette pricing.

Time for you to do some teeth counting.

 

[flux]

I will check tonight, but i've a feeling it might be riveted.
The cover in front of it doesnt seem to have anything to unbolt, so i'd guess the pedal and crank will need removed to get at it. Will need to look whats needed for that. Plenty of motorbike tools, not so much for bicycles.

 

[flux]

looks like there is maybe access to bolts from the rear..

 

[flecc]

Better a few more teeth on the front then than a few less on the back?

Yes always. Less wear and higher efficiency, the chain not having to turn so tightly around small sprockets.
.

 

[motomech]

You should be able to get 11/48 gearing on that bike. Since you will only use the sm. gears, just get a cheap cassette and replace it when the 11 T wears out.
There is more to tuning up the derailleur than just "aligning the chain" and making it shift. The placement of the last idler wheel in the correct position relative to the cassette is important to making the gears last. I suggest you study the procedure, Sheldon Brown is a good place.

 

[Deleted member 4366]

You should be able to get at least 5000 miles out of your top gear because the gears on bikes with hub-motors don't wear out, not even the top gear, and not even the cheap ones. You should be able to get at least 5000 miles out of it for normal road use.

Those freewheels normally have a 14T top gear. I always use DNP freewheels with 11T. Mine's done 4000 miles so far and isn't showing any signs of wear.