Bikonomics II

(Doesn’t have the same ring as Freakonomics.)
In a previous entry, I tried to quantify the economies of bicycle commuting. There were several interesting comments that I wanted to call out.

Mitch writes: I dunno about not including the clothes. You don’t need special clothes for driving, but you need at least a decent pair of bike shorts. And to keep up with the other bikers, it seems that a jersey is almost required, although I am staying with t-shirts for now.

For commuting, I wear a t-shirt and gym shorts, unless it’s cold, where I’ll go with tights and a jacket. The jacket (made of Tyvek) was free at a cycling event. I only use my jerseys and padded shorts on recreational rides over 20 miles. Currently, I swap the basket of clothes out on either Thursday or Friday.

Sarah wrote: You know, if you calculated in a gym membership fee to keep you fit enough to be able to bike to work each day i think you might find that you are actually doing quite well economically. Just a thought!

This is a very good point, Sarah. Although I really ought to be doing weight training exercises (osteoporosis and all that), I still get nearly two hours of aerobic activity in with each day’s commute. If traffic is thick, biking takes about the same time as driving. As Claire noted, I avoid the overhead and irony of driving some place to work out.

Jim wrote: Jim, you missed the single most expensive thing – fuel! I did a cost analysis for the extra calories I burn to get to work by bike (24 miles at 800 calories) and found that gas at $3/gal is cheaper than food to fuel my body.

I deliberately left off food. My commute’s short enough, and I could benefit from, um, running a caloric deficit. On event and recreational rides, I definitely bring along a few bars of something. I also have some favorite stops along the way like Sandy’s Espresso in Carnation.

Claire wrote: As for car insurance, you sure you can’t get a reduction in your insurance if you’re a bike commuter?

I checked into this. By driving to work two or fewer days a week, I’m considered “pleasure use only.” It will save about $28/year.

If you were going to participate in these events, anyway, I think some of your cycling costs are going to be incurred whether or not you’re commuting.

Absolutely. My training for RAW was mostly sustained commuting. I ramped up mileage by adding a weekend event or training ride. Like a workout, I’m not sure how to quantify the time.

The real question is: does someone save who is not a recreational cyclist? [...] She rides a mile to the bus stop, uses her company-sponsored bus pass to get a ride to Montlake and puts the bike on board, and then rides a couple of miles to her workplace. She’s riding a 20 year old mountain bike that was a garage ornament before. Total investment to date: $35 on a new bike helmet.

On the one hand, your neighbor is far less likely to have a flat. Would she previously have driven? Or left the car at a park and ride?

It does underscore the $137.11 question about whether my fancy-pants clown bike is suited for the rigors of daily commuting. For example, on Thursday my tire popped. The boom was spectacular, but the tire was destroyed.

Woodstock added “Think of all you’re saving in medical bills because you’re fit. Plus, mental health is worth more than it’s possible to determine in dollar value. Just imagine how much higher your blood pressure would be if you drove every day. [g]“

I feel much more stressed out on the day a week I do drive. :-) Although I can’t quantify it in terms of dollars, my blood pressure during my recent physical was the lowest it’s been for years.

Reid wrote “I also did some calculations on the cost of bicycling [...] As of this moment my cost is about $0.49 per accumulated mile; you’re running $0.26, but I did include “capital” costs.”

Reid and I had a side discussion on this and whether replacing a chainring would be considered a capital expense. I didn’t think so. Using the airplane as an example, the capital expenses should be relatively fixed over time because some parts, like the frame, last “forever.” Components with measurable and finite use would be replaced on a regular basis. From an accounting point of view, you’d start off with a bike in pristine condition and maintain a separate account for maintenance as item met their fate. For example, if a chain is expected to last 1,000 miles and costs $100 — I’m picking very round, easily divisible numbers here — you’d contribute $0.10 per mile to the maintenance kitty to offset the decline in value of the component. A set of aero bars is a capital investment. My replacing wheels, but upgrading to disc-based hubs for eventually adding disc brakes is a combination: the rims, labor, spokes, etc are maintenance, the hubs are capital expense. There’s some tricky math should I sell my old Ultegra hubs, but that’s the simplified version.

This is obviously contrived because no one maintains a separate account for maintenance. (The same is for homeowners, how many of you have a savings account for a new roof?)

Now, as far as capital expenses go, my cost is currently about $0.45/mile. I could have greatly reduced this
by buying a less-expensive bike. Using a car analogy, I have a Mini while others have Honda Accords or Porsche Cayennes.

DrLith said “That’s a boatload of money on major repairs and tuneups! Having to replace your wheels with less than 3K miles really sucks. I think it’s more typical to get at least 10K. I’d be religious about keeping my brake pads clean if I were you.”

Since replacing the wheels, I’ve been hosing off my bike when I get home. I also tried to hedge my bets against future rim deterioration by getting disc-based hubs on the theory that I could have braze-ons and brakes added later.

Maintaining a car is an expensive exercise that loads up over time as well; the ratio of consumable auto expenses to part replacement expenses has to tilt at a fairly early point in a cars life. When that happens, you can buy yourself the entire bike (and sometimes more) guaranteed yearly.

Yes. I realize I calculated the car maintenance incorrectly and esitmated low. I should have picked a longer horizon for the car to factor in bigger ticket items like replacing the timing belt. Historically, I’ve kept cars about six years. My last bike I had about 11 years, but most of that was it just sitting in the garage.

Another thing I didn’t include was the annual expenses unique to a car, specifically license plate registration, which runs about $90 because of various fees.

Kermit wrote: I particularly like the fact that you calculated the amount of maintenance costs attributed to actually commuting. A lot of people skip that. [...] Basically, you should be able to google around and find a more accurate number for this. I believe that it will be quite a bit higher, perhaps even $0.30 per mile.

You’re right. Earlier this week CNN/Money posted a general guideline on maintenance costs. (This works out great because I’ve calculated depreciation, fuel and licensing expenses.) Their estimates ranged from a high of 7.35 cents-per-mile in San Francisco to a low of 4.69 cents-per-mile in Bismarck, North Dakota. Let’s split the difference and call it 6.5 cents per mile. That’s almost 9 times what I considered as part of the oil change.

Conclusion: Last week I had shown that biking was costing me $137.11. If we apply the quantifiable changes above, we see the car is now slightly more expensive:

Maintenance: $0.065/mile (see above) * 1,840 miles = $119.60 – $13.25 (what I calculated last time) = $106.35
License tags: $90
Savings on auto insurance: $28

($137.11) + $106.35 + $90.00 + $28 = $87.24

Finally, for Susan’s amusement, I include a Gartner-equivalent Magic Quadrant