For the same reason GM doesn't offer all weather tires for Vettes and ZL1/1LE/SS Camaros... they're idiots.
I like to drive year round as long as the streets are clean of snow and ice, but with summer tires it makes it impossible.
C'mon GM, give us the option when we order our cars, summer only or all weather tires. DUH!
Can't help you with your flat on your JD tractor. I machine the rockshafts, rockshaft assemblies, lift arms, center link brackets, drawbar brackets, and drawbar frame brackets. I have nothing to do with the tires.
