The Patterson Metropolis 2-speed crank drive comes stock with a 28t chain wheel. If thats not adequate, there is a 130mm adapter available from Patterson, to be able to mount chain wheels starting from 38tooth size to the Patterson Metropolis. I got one and mounted a 42t chain wheel to my blue Sprint, but I think I’ll get a smaller 38t for better hill climbing later.
A couple of weeks ago Sam Patterson noticed me that Ti-Trikes will offer 34t and 36t chain wheels for the Patterson Metropolis. They are not listed on their website yet, though.
Unfortunately, the Patterson Metropolis is not very forthcoming to mount a Pedelec sensor when mated with an electrified cycle. I’ve tried sticking some neodymium magnets into the chain wheel mounting screws, but the distance to the sensor was a little bit too big to provide reliable function.
Fortunately, someone offered a simple and affordable, but pretty well made DIY Metropolis Chain Wheel Adapter at Ebay, that provides enough space to mount the magnets directly to the adapter. If he doesn’t offer the adapter, send him a notice, he might have one left, or is able to produce one for you.
I’ve simply drilled ten 5mm holes into the adapter and glued the 5mm neodymium magnets into it.