Love my new RadMini, but found the gearing a bit low for my tastes. Lower than the Rover, probably due to 20" v 26" wheels. After looking on another thread and call Rad, I did the following.
Purchased a DP 11/28 Freewheel on Amazon for $32 (free shipping with Prime). (DNP Epoch Freewheel 7spd 11-28 Nickel Plated)
Purchased the "special" rear cassette tool from Rad for $5.00 (the guy in tech said many shops didn't have the specific tool for the Rad Ebike).
Took it the local shop, they charged me $10 to change it. The mechanic at first said they had all the tools needed, but later said he did need the special tool from Rad. Just FYI.
It's more than a 20% change in top gear (11 v 14) and is quite noticeable when cruising at speeds in excess of 15 mph. The low gear (28) is unchanged.