The switch to radials occurred in the 1970's. Imperial first adopted radials as standard equipment in 1974 - LR78x15. The New Yorker adopted JR78x15 the same year. In the late 1960's manufacturers adopted belted tires, usually polyglas, but they still had biasply sidewalls. The switch from letters denoting the tire size to metric occurred around 1978-1979. Thus a GR70x15 became known as a 225/70Rx15. Bill Vancouver, BC ----- Original Message ----- From: Cebuisle2@xxxxxxx To: mailing-list@xxxxxxxxxxxxxxxx Sent: Sunday, March 13, 2005 7:14 PM Subject: IML: cracking wheelsd Thanks guys, for the input. It must have been the radial tires I installed on the 65. Don't remember just when the manufacturer switched from bias plies to radials-must have been around the mid sixties. As I mentioned, I solved the problem by installing earlier rims (1955's) on the car for trips. Never had one crack. Perhaps there was more metal in the earlier wheels. TED ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm