I'd like to set up a bike as a grocery-getter that's able to carry 4 grocery bags, two in front and two in back. My dream is to take the bike grocery shopping or over to the farmer's market. I was going to use my old Shcwinn LeTour but then I realized that groceries can get pretty heavy and I'm not sure how much weight you can carry on the 27x1.25 tires (they look about the same size as 700x28). I also have an old mountain bike with a rigid fork, would that be a better choice for carrying a lot of weight? I weigh around 185.
I suppose I could post this on the commuting board but I thought people here might have more experience with carrying a lot of stuff.