I have worked for Americas/Discount tire for 30 years here in Nor Cal and in Arizona. I have seen many failures on all kinds of tires. I will say that trailer tires get a ton of abuse from the stress when backing up the trailer and putting a bind on ...
I live in Northern California and have road my Harley many times through those areas. I recommend taking 88. You will love the scenery.4 over ebbetts pass I would not recommend. Hope that helps.