Originally Posted by
alexw
... Judging by the overall condition, aside from the cracks, not very old. They still have a lot of the knobbies on them from the manufacturing process.
Judging from your description of age/condition ^ , I would think these cracks are likely the consequence of poor manufacture and/improper curing. I would be very leery of it, and I would NOT recommend that anyone ride on them for that reason.