That tirerack deal seems pretty decent. I know this is a small subset of users, but for any Travelocity Amex holders, they offer (through Barclay Rewards Boost) 3.5 points per dollar, which translates to 7% bonus plus whatever your normal points accrual is (typically another 2-4% depending on the version of card you have).

Also to note on DiscountTire via redemption portal... I had a warranty claim on an old set of tires because they wore out before the mileage intended, so I didn't purchase online thinking that I would not get credit for the old tires. However, now figured out that you don't actually transact on DiscountTire. When you click through to purchase tires online, you schedule an appointment but never enter your credit card info, so theoretically you should be able to then show up at the store and handle any warranty credits while presumably still getting credit for the link-through.