[Supercar_Kid]

I think it's typically more of an expansion and contraction issue than actual hauling on the wheel. It seems mating molded plastic to a steel core just doesn't create a steering wheel with great longevity. Rosewoods and walnuts seem to always crack at the spokes. (3,6, and 9 o'clock) It seems to make sense to me that these wheels are most rigid at their spokes, and the plastic isn't, therefore the slightest shrinking or expanding of the steel core will create a stress crack in the plastic. The plastic seems to have a tendedncy to shrink, leaving gaping 2" cracks fully exposing the steel core in some instances. Take a look at '69 standard wheels, they seem to crack as often or more often than an N-34 type, and again, always where the bar meets the rim, and especially where the wheel mounts to the column. I think the design of these standard wheels is even less forgiving of an out of synch expansion and contraction of the core and plastic covering. It seems this was a common problem on similarly designed wheels of all makes and models, it's not just a Chevy or even GM thing. That's probably why the hard plastic wheel seemed to all but disappear by '73 or so, being replaced with the big squishy rubber wheels we're used to seeing in more modern cars. I agree that manual steering and excessive pulling on the wheels, especially from getting in and out of the car, can help a wheel that's ready to crack get strated, but I also agree with Camarojoe that I've never seen a vintage uncracked wheel crack, or even an already cracked one get any worse. I think most wheels cracked while they were fairly new, if they were gonna crack. Any original owners here remember their wheels cracking, or even going to a dealership under warranty to complain? It might be a neat experiment to try to make one crack by putting it in the freezer and then rapidly warming it up, although I don't think myself or anyone else has an uncracked rosewood they'd like to subject to such an experiment.