by paul gage » Sat Mar 16, 2013 8:48 pm
I usually keep my cars resting on their sides on a thin layer of spongey foam from computer hardware packaing, mostly because I've run out of shelf space. I do keep my display favorites sitting on the tires, sometimes for months without using them. I also see the small line on the tire but I have not detected a flat spot when the car goes on the track. Most of my cars have the softest XPG tire I make. When I take them off the shelf there is the same grab. I don't think it is stickyness but possibly vacuum. The small line may simply be the clean spot and a fine layer of dust has collected on the rest of the exposed portion of the tire. This in no way a scientific conclusion though. I usually just pick up a car and run it, perhaps giving the tires a quick 10 second spin on 240 grit sand paper if the car is loose in the corners.
Most of our local racers were using urethane for a couple of years before I came along and none have made any comments about storage having any effect on the tires. I replaced a pair the other day that was reportedly 6 to 7 years old, only because the looked ratty compared to the tires from my newer mold types, they still worked awesome, and no flat spots or anything.
If you get a bum pair let me know and I'll fire off some replacements... hope I helped... cheers...PG