Tires with Nylon cords will develop flat spots from sitting in one place. Fortunately, these will smooth out in a few miles of driving, unless the temperature is really low. Nylon cords were used in bias ply tires in the late 60's and through the 70s; there may still be a few around on collector cars. Almost all "Radial" tires use steel belts under the tread; these don't take a "set", but they can certainly fail. The more common failure in a radial, though, is a ply separation, in which an area of the tread rubber takes leave of the casing, causing a bump each time the wheel goes around, and ultimately the complete failure of the tire when it loses a patch of tread rubber. Often this happens without losing air from the tire, in which case you can limp to the next offramp before changing the tire. If you are feeling or hearing a bump or slapping noise as you drive down the road, you have a tire that is about to lose a chunk of tread. Have someone ride alongside you and listen to determine which tire it is, and get rid of it fast! Out here on the 85 MPH freeways, I hear cars and trucks come by me all the time with a bad tire making the noise - I quickly get away from that vehicle - it is about to have an exciting event and I don?t want to be there! Dick Benjamin -----Original Message----- From: mailing-list-owner@xxxxxxxxxxxxxxxx [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx] On Behalf Of RandalPark@xxxxxxx Sent: Friday, June 03, 2005 5:56 AM To: mailing-list@xxxxxxxxxxxxxxxx Subject: Re: IML: Tire expiration ?Radial vs. Bias Ply I have noticed that my old bias ply tires develop flat spots. If the cars are driven frequently, these usually smooth out. If they sit for longer periods, they don't. I think that the longevity of either style of tire is going to depend on the amount of quality put into the product. Poor quality will result in faster deterioration from age and use in either case. My Imperials do the best all around with high quality radial tires. Paul W. In an email dated 3/6/2005 1:11:22 pm GMT Daylight time, Black55Imperial@xxxxxxx writes: >I have original type bias ply tires on my 3 Imperials and have had ?great >service with no cracking or lumps beyond the 10 years mentioned. ?The ?cars are >stored inside with humidity control and away from sunlight. ? However, the >original radial tires on some of my 70s collectible cars with under ?10,000 miles >began to give lumpy rides.. ?These cars are not driven at ?highway speeds and >never in winter. ?These radial tires seem to have the ?belts break after time >where bias do not show the same type deterioration. ? > >Have others noticed a difference in the aging properties with raidal vs. ? >bias ply tires ? > >Randy Still >black '55 Imperial Sedan >gray '56 Crown Imperial Limousine >turquoise '64 Imperial Crown Coupe >black55imperial@xxxxxxx > ----------------- 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 --- [This E-mail scanned for viruses by Declude Virus] --- [This E-mail scanned for viruses by Declude Virus] ----------------- 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