Holy crap that seems odd to reduce the tread height only is specific areas of a tire. But I suppose it would be better to have irregular tread heights than chase an imbalance through the whole life of a tire. I do know that some tires will take a pretty heavy "set" when parked too long too.. thump thump wobble wobble til they get driven a bit more.. and wonder if that pre-warming roller setup even comes close to mimicking the actual heat produced by higher speed driving. I think Larry's probably right too since both of those tires appear to be bias ply designs. One of the reasons that I only buy premium tires these days is higher quality control and if somethings not perfect?.. for the money I typically spend an RMA surely gets issued for a swap out. The only real issues that I still run into on occasion is irregular tire balance(lopsided tire weight) which results in the tire having to be spun on the rim to not end up with 10 ounces of weights taped to the damned thing. I remember one shop had 16 ounces of weights taped side by side! Imagine that weight flying around at 90 mph compared to what the balancer showed at much lower wheel speeds. Of course rims aren't exactly perfect either with the cheaper aftermarket stuff being way off from OEm sometimes too. Even with specific instructions to avoid excessive balance weights, I have had them strip excessive weights off several times through the years just because the tire guy was too lazy to read the work order notes and/or do more work to keep the balance weights down. IMO, it's also well worth the extra ching to have any performance tire "road.. or load balanced" since the belts overlaps and slight real world imbalances created when the carcass is rolled against a solid surface.
Agreed. It's no coincidence that these machines disappeared in the mid seventies when the radial tire started becoming popular after the gas crisis, and Goodyear finally figured out how to mass produce them.
