Generally speaking, on a dollar-per-mile basis motorcycles cannot beat small cars.
Put pencil to paper. Calculate the cost to drive a motorcycle 100,000 miles versus a small car. I've gone years at a time with no car and kept detailed records. Bikes are more expensive.
Consider:
- Motorcycle tires are expensive and need to be changed about every 8-12,000 miles. (order online, buy your own tools)
- Service intervals for oil, filters, shocks, chains/driveshafts, and valve adjustments are much shorter.
- Motorcycle depreciation is fast and severe.
- Add in several hundred dollars for helmets, body armor, gloves, boots, rain suits, etc. which must be periodically replaced.
Be aware that most Japanese motorcycle dealers refuse to work on bikes older than 15 years, as parts for old Japanese brands are difficult to purchase. A few BMW and Harley dealers will. Most will not. Visit your local independent mechanic before purchase and see if you like him.
Maybe I just don't care of my bike well enough, but I don't think the recommended service intervals are remotely near necessary.
Perhaps more likely, people often ride bikes really fast, accelerate a lot, brake hard, and all that wears out components much faster.
I haven't had to do enough maintenance to be sure, but it seems that stuff wore out faster when I was young and drove fast than they do now.
In 34k miles, I've replaced the chain once ($50), and replaced the crappy stock tires with premium racing tires for better traction (Dunlap GT105 and a Perilli Sport Demon - roughly $200 combined, plus don't remember how much for the shop to mount them).
I haven't done oil changes any more often than in my 4-wheelers, but it uses 1/5th the oil each time, and a cheaper filter.
34,000 miles, at my bikes 65mpg used up 523 gallons of fuel, or $1569 at $3/gal
In a 35mpg car it would have been 971 gallons, or $2913 at $3/gal.
$1,344 is a whole heck of a lot more than the total I've spent on safety gear (much of it used, shopped for best internet price for what wasn't, and I don't see why I would need to replace any of it under normal circumstances (I've made some upgrades after learning more about my options, but the gear I first bought back in 2001 is still in service).
As Grant pointed out, depreciation on an inexpensive asset is pretty much irrelevant - 20% on a new Land Rover is around $26,000; 20% on a used EX250 is $200. $200 is fairly negligible compared to $26,000.
Then there is $75 a year insurance, compared to $476 for my 4-wheeler, and the fact that I never have to pay for parking or bridge toll on the motorcycle.
Another variable is the gamble that you won't suffer life-crippling injuries that destroy your ability to earn income in the future and saddle you with enormous medical bills. I personally know several people this happened to. Accountants call this http://en.wikipedia.org/wiki/Contingent_liability Estimate the dollar value and post it as a cost.
"In addition to being the leading cause of death among U.S. residents aged 5--34 years, motor vehicle--occupant injuries account for approximately 15% of all nonfatal injuries treated in U.S. emergency departments (1). In 2005, the lifetime costs of fatal and nonfatal motor vehicle--occupant injuries were estimated at approximately $70 billion, including costs for medical care, treatment, rehabilitation, and lost productivity"
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5951a3.htmYou take that gamble every time you get in a car too. Just because its so common that we don't think about it doesn't mean that the risk is not there, and fairly large.
Contrary to popular belief, there actually isn't any evidence that motorcycle riders are at higher risk of accident than car drivers. There is lots and lots of concrete evidence that the average motorcycle
driver takes more risks than the average car driver. Bikers have significantly higher rates of speeding, drunk driving, driving without a license, reckless driving, etc. and the higher rate of unsafe driving alone accounts for the majority of the difference in statistical accident rates. The one study I am aware of which actually controlled for driver behavior (by looking at a single subset of all drivers - police officers - in Kent County England) found the motorcyclists to have a
lower accident rate than their car driving equivalents. The single biggest reason for motorcycle accidents is the choices of the rider (which we can choose to change for the better), the second is visibility, which can be improved with additional lighting (and modulators), reflective tape, and bright colored gear and helmets.
Now, it is possible that even taking all that into account, motorcycles still carry a slightly higher risk, but you can only compare any increase in risk that you specifically have over your risk when driving a car, not just the risk for the average motorcyclists compared to sitting at home.