Walmart is not a bike shop? Weally? And no, not any bike shop will have those, none of the three in our town do and when asked about special ordering they looked dumbfounded...welcome to Fort Wayne Bike shops; none of the FTW LBS's will even deal with a Walmart bike, it's beneath them! Supposely due to impossible to get non-standard parts Denalli and the Schwinn that Walmart carried uses, and it would cost more then the bike is worth to convert over to standard parts when the non-standard parts fail. I don't own a Denali, I bought the Schwinn they use to carry last year for my daughter but took it back after problems; but it too had the Schrader valve 700c tires, that's what led to inquiry. Ended up getting a excellent condition used Cannondale that fit her from one of the LBS's in town and she likes it better then the Schwinn, and it's a lot lighter.

NONE of the LBS's even cared to mention that 27" tubes would fit in a 700c tire-go figure.