jdog,

we at Danson are putting an auto tire on the 650's now. with the miles you ride,  you would be way ahead to do it also.  it is a Bridgstone potenza tire 165-65-14.  i think it is around $60. it  is kinda a pain to put on, but, the effort will be well worth it. there are some posts on here about how to do it, or you can give Danny at Danson Trikes a call and he can instruct you. good luck.

Mike (Danson Trikes)