New cassette on Jumper. Not possible?

[Peter]

Some weeks ago I had my Jumper for service at my local ebike dealer. I told him to change the rear cassette so that it fit higher top speed. As the bike is now my legs spins like crazy at 40 kmh.
My top speed on flat tarmac is 40 kmh.


He said this was not possilble. Is that really true.

 

[pxpaulx]

Most rear cassettes, including the shimano ones easy motion uses, only go down to 14 teeth on the smaller sprocket. There is only one company that makes a smaller cassette with an 11 teeth smallest cog, they are called dnp. You can find them online or on eBay for about forty bucks. You'll have to check whether the mount is a cassette or freewheel, the dip is a freewheel. Most motors are freewheel as well so that shouldn't be an issue. I would talk to the shop tech about it first though!