In one of their catalogs,they claim the chemicals in Wesleys pulls the oil out of the white wall, causing premature cracking. I have had trouble with Coker tires cracking,and they would not warranty them. Diamondback claims their white walls will never crack or turn yellow,but don't use Weselys on them. Never store tires so black is touching white,that will cause yellowing in that spot. I once leaned two tires against the wall,while I pulled the rear axle. After several weeks I had a yellow spot about 2" X 1/2",that spot won't come out.