man it i so easy you just get a dremmel or such like and put in the grinding disk and use the back edge of the tyre rim to cut against.
then take that which you have just cut off and glue it to the front simple.
if you get stuck have a search on the fourm there is a little guide somewhere.
if you cant find it i will make a new one.
or if you can not be bothered then i can make you some.(just cover the cost of the wheels plus the postage).
any more help you need give me a shout.