The 21" would look sweet on your bike. JMO

 

anyone got any pics of a slim with the wheels changed out ?? keen to get some ideas !!

 

Most likely you can use your hub and a 21" rim (make sure the spoke count is the same), re-spoke the wheel and you should be good. Leaving the fender off?

Check with any number of wheel suppliers and they will walk you through it.

 

I have a blackline and I'm willing to trade front wheel. Contact me
danjolliff@gmail.com