Okay, my trike is built on an IRS system and with that, run the 4 lug VW bolt pattern. Now I don't know about anyone else running the 4 lug drums, but there really isn't a very good selection of wheels available that spark my interest. I currently have some EMPI 8 spoke wheels on the trike, which look okay, but would like to go to a different style that is only available in the wide 5 lug type wheel.
Now, I did some research and found that a person can in fact convert to the wide 5 lug in two different ways.
The first way, which is probably okay, is to put the wide 5 lug on and use a spacer between the drum and axle bolt.
The second way, which I would prefer, is to use a 1973-74 VW Thing drum. Even though these had IRS transmissions, they still used the wide 5 lug drums and wheels.
Here is a source for getting these drums:
http://vwparts.aircooled.net/Rear-Br...1-501-615a.htm
Of course this is early research so I might edit this post to add better/more availability on these drums.