People who promote bicycles for transportation often note how cheap it is to ride a bike. But there are no definitive studies (at least that I know of) that tell us just what cycling costs. There is a danger that we oversell bikes and leave the impression that bike riding is nearly free. If we want to encourage people to keep riding, they need to begin with realistic expectations.
So I worked up a quick estimate using two different examples. The first starts with the purchase of a fully-equipped (or accessorized) $1200 commuting bike. It has stout tires and an internal-gear hub for low maintenance. I assumed that a $50 tire would be replaced every 3000 miles, and that the bike would need $100 worth of service every 3000 miles. In addition, it would require major service, costing $200, at 15,000 miles. I further assumed that the bike is ridden 2,000 miles per year, and after 15 years or 30,000 miles, it would be worn out (of course it could probably be refurbished for less money than it would cost to purchase a new bike, but I have to have an end point for my analysis).
The second example is a $5000 sport bike. Maintenance costs are a little higher because the tires don’t last as long, chains and cassettes are subject to routine replacement, derailleurs require fussing with. I assumed that a $50 tire is replaced every 2000 miles, it requires $120 worth of service every 2500 miles and major service every 5000 miles that costs $200. I assumed that this bike was also ridden 2000 miles per year and lasted for 15 years.
As far as I know there is not data set out there to get real numbers from. These estimates are based on my experiences as a bike mechanic and tracking maintenance requirements on my own bikes. I think they are reasonable ball park estimates.
For this first cut, I am leaving out uninsured crashes or theft, or the cost of any additional insurance. I am also leaving out clothes, helmets, and other accessories (and clothes might be significant with the $5K sports bike). I am also assuming that the bikes are purchased with cash.
I discounted all of the future costs to present value (PV), then projected the PV out into annual payments, using a 3% discount rate.
According to this analysis, the commuter bike costs $193 per year, or $0.10 per mile. The sport bike costs $564 per year, or $0.28 per mile. Half of the cost for the commuter bike is the initial purchase, so either doing your own maintenance and buying cheap tires, or buying a $600 bike with the assumed maintenance could get the cost down to something on the order of $0.07 per mile.
The initial purchase of the sports bike accounts for $0.20 of the $0.28 per-mile cost; buying a $2000 bike gets costs down to $0.16 per mile. The lower-cost-maintenance program for the commuter bike (at $0.05 per mile) costs $0.03 less per mile than the maintenance on the sport bike (less difference than I would have expected).
The maintenance costs for this analysis are insensitive to the number of miles traveled per year or the length of the life of the bike, but total costs are sensitive to the assumed bike life, since the initial purchase price is proportioned out over that assumed life.
On a per-mile basis, this is cheaper than cars, but not as much as you might expect. AAA puts car costs at $0.55 per mile for a small sedan driven 10,000 miles per year, and up to $0.91 per mile for an SUV driven the same distance. The small sedan costs just under $0.04 per mile for maintenance, and the SUV does not cost much more ($0.0547). The rest of the cost is fuel, depreciation, insurance, finance charges, etc. Since some of these are fixed costs, per-mile costs go down if the car is driven more, and there are some costs even if the car sits in the driveway, so if you subsitute bike miles at $0.10 for car miles at $0.55, the actual cost of the miles you actually do drive the car go up a little.
Of course the real-world difference in cost between cycling and driving is created by the fact that the car empowers and obligates people to drive 10,000 and more miles per year. (While this kind of mileage is not impossible on a bike, and many competition riders actually do ride this much, you won’t see many utility riders putting in this much travel time.) Cars are a powerful tool, but they can be a curse when people have no alternative to spending enough time in their cars to drive 10K to 15K miles every year and spend $5500 to $11,800 per year (according to the AAA document) just to survive and participate in life.
So the trick is to arrange your life – and your cities – so it is a viable option to pay $193 per year to ride a bike 2000 miles, rather than the $11,800 per year to drive an SUV 15,000 miles.