Walmart doesn't true wheels. From what I've seen if you buy a preassembled bike from Walmart you're lucky if the brakes are useable without adjustment.
Sadly most people buying bikes from Walmart know almost nothing about bikes and can't/won't fix anything themselves. It's probably best that any bike from Walmart be disassembled (everything, whether it was assembled at the store or the factory) and reassembled and adjusted bike someone who knows what they're doing.
If there is a problem Walmart will exchange the bike (and typically resell it at a marked down price, with no consideration to whether it's safe), but if the wheel isn't really god awful it's probably not that different from what you'll get if you exchange it. And since the exchange will be the whole bike you never know what other problems you will acquire.
There is a bike store version of the same bike. Not much more expensive and it comes with MicroShift brifters instead of RevoShift.
Last edited by NightShift; 07-14-10 at 06:55 AM.