Only 2 bikes? That's it? Do your own work. My gas costs $2.55 a gallon now. Over the last 6 years I have averaged 2,000 bike commuter miles each year. You do the math. Got good health? Nothing more costly than sitting on your butt and eating a bag of chips. BP 110/60 for years now. Studded tires should last 5-10 years. Cheers & pedal on.