I ride in jeans all the time, and any other pants I happen to be wearing. No problems. Being naturally thin at 130 lbs, my quads don't get huge no matter how much I ride and run. I am glad to see a large business recognizing the idea that people do ride in everyday clothes and not just spandex. I've been riding in everyday clothes since I was a kid. However, those pants don't even look good or comfortable in the pictures on the Levi web site with their model. They might want to put a bit more effort into making something that looks better.