IF Walmart is your only tire shop around, go for it. Walmart could potentially 'update' their warranty according to the manufacturer too. I use to work at Sam's Club Tires and warranty for certain tires would always change but that's the kicker, they could purchase our 'life time warranty' if anything happened to the tire. I haven't worked there since 2008 so I'm assuming A LOT has changed since then, maybe.
Anyways, I would highly recommend Discount Tires if there is a Discount Tires near you. I went from working at Sam's Club Tires to Discount Tires and they're HEAVY on customer service. Discount Tires will do basically anything to keep their customers and keep them happy. Lots of 'positive' stories at Discount Tires compared to Sam's Club/Walmart from my experience.
It's worth the extra $$$ at Discount Tires. Especially if you let them know your driving situation.
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View my fuel log 2015 Mirage DE 1.2 manual: 43.4 mpg (US) ... 18.5 km/L ... 5.4 L/100 km ... 52.2 mpg (Imp)