Originally Posted by CrankyOne

Usually the biggest problem with heavier weight is spoke failure, then rim, then hub. I'd think tires would only be a problem if they're under-inflated and you get a pinch flat. This is one reason I don't recommend 'English' style bikes like Breezer or Bobbin, or looks-like-a-Dutch-bikes or looks-like-a-retro-bikes for people looking for a city bike that will be used for carrying groceries and such.