I have a Cruiser that is over 10 years old that is still going strong except for one thing. The left twist shifter was always pretty stiff, but now it is nearly impossible to twist with one hand. No dealer has been able to improve it. My husband lubricated it, but no improvement. I don't know why they put such a terrible shifter on a trike that is used by a lot of older people with arthritis. Is my only option to replace it with a completely different type of shifter? Any recommendations? Thanks!