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