Go to www.tompatterson.com and do a search on SmarTire in the archives.
Restrict your search to the Vintage Airstream List and you'll find a number
of postings about the system.
I have one and like it. It's easier if you read the archive search first,
then ask any other questions.
Roger
Roger Hightower
WBCCI #4165,VAC
1975 31' Sovereign
Mesa, AZ