I had a Wally World Schinn MTB once. 1/4 mile from my house on a commute to work and the chain started slipping. It was intermittent but happened mostly under heavy pedaling. Put 100 miles on it total as I never trusted it. Took it to a mechanic one day cuz I wanted to sell it. 3 broken teeth on one gear on the freewheel. Last Wally World bike I'll ever buy.