I weigh 185 - bike and the crap I carry is usually about 65 pounds. I use friction drive on an old Schwinn 10-speed. Rear tire was 27 x 1 1/4, then I switched to 700c in rear. Even on the cheapest 27" tire, I would get about 1000 miles. You can find 700c tires with much thicker tread than 27" tires, so now I get 2000 miles (a year of riding for me) before changing. I use $10 Kendas and similar.god no never a friction drive. my wife says they burn!