A slightly politically incorrect question.
In predominantly Mexican-American neighborhoods in cities like Austin, Los Angeles and El Paso, I've found that there's literally tens of used tire stores. I mean, they're everywhere in those neighborhoods.
"They're poor neighborhoods", you might say, "and residents can't afford new tires." Maybe, but used tire stores don't seem as prevalent in poor black and white neighborhoods. Also, it seems like in lower-income Hispanic neighborhoods, used tire stores are so common it seems as if to an outsider, a typical resident would buy a set of tires every week or so.
I don't think anyone solved the mystery of the concentration of dentist's offices in poor neighborhoods. What about the concentration of used tire stores only in Hispanic neighborhods, though?