Hi Daniel and
![](https://i.imgur.com/evDSMvT.png)
to the forum.
Have you tried contacting any of the GM dealers shown on the
Dealer Listing to see if they have stock?
If your wife's bike has a 7 speed splined cassette:
![](http://www.sheldonbrown.com/images/freewheel-vs-k7.jpg)
you will also need to purchase a suitable thread on freewheel to fit the threaded boss on the Smart Pie's hub.
The cassette has a splined locknut which secures the cassette to the freehub and rotates with the sprockets:
![](https://www.parktool.com/assets/img/repairhelp/Cassette-006.gif)
Whereas the freewheel has the removal splines on the inside of the freewheel unit which is fixed to the wheel:
![](https://www.parktool.com/assets/img/repairhelp/Freewheel-003.gif)
If you are not sure which type you have,
Click here for further information.
Alan