The free motorcycle equation

Dailies -



It’s hard to explain the appeal of motorcycling to non-initiates. Doubly hard if those non-riders are also math geeks. This equation, created by HFL reader Ben Kester combines fuel economy, gas prices, and the price of a new motorcycle to tell you how many miles it’d take before that bike will pay for itself over your car. If you buy a CCW Hooligun, that pay off could come as soon as 24,375 miles.

So in this formula, CF = car fuel economy (mpg); G = price of gas per gallon; BP = bike price; and BF = bike fuel economy (mpg).

Ben’s car nets him 22mpg, which is pretty average, so it’s a good point of comparison. Add an estimated 85mpg for the $3,490 Hooligun and the payoff comes in 24,375 miles. That could be a single year of commuting for some people.

Ben explains that this formula is somewhat over-simplified, “The formula certainly has limitations in that it excludes insurance, gear, and consumables like brake pads and tires.  Those concerns are probably offset to some degree by the lower amount of wear and tear that are put on the car that is now sitting in the driveway.”

“I wrote it up the way I did so that:
A. I could catch the attention of some of my friends that would normally ignore a post about motorcycles
B. Send more traffic to the CCW guys so that they’ll hurry up and offer the Hooligun and Ace
C. I wanted the formula to be fairly easy to plug numbers into “

 We ran this formula past our resident numbers guy, Nick Goddard. I can’t do math, but he assures us it checks out. Nick adds that he uses a similar formula, but thinks of it as a discount on a more expensive motorcycle, which is probably applicable to more people. “The trouble is that a moped has a very low payoff mileage,” explain Nick. “So you think “I’ll get a sportsbike and just ride a little farther” but a sportsbike loses a lot of the mileage advantage and costs much more… that’s why i think it’s better to think of getting a discount, rather than looking for total payoff.”

Plug in an R1, for example, using 20mpg for the bike, 10mpg for a hypothetical car and a $12,000 as the bike price and it’d take you 68,571 miles to recoup your money using $3.50 gas. But, you’ll achieve a 20 percent discount on that bike purchase after just 13,714 miles, which is a reasonable year of commuting.

Ben’s applied his formula to his own life, saying, “Two years ago I bought my first bike, a 1981 Honda CM400t for 800 dollars, and I’ve been having fun customizing/fixing it and riding whenever it’s above 35 degrees out. I’ve put about 6000 miles on it mostly riding to Indiana University (I’m a graduate student in Biochemistry).  Using the same approximations, that bike will pay for itself in about another 2000 miles.”

  • Peter

    Where BP = bike cost + gear cost + license costs + insurance cost.

  • stickfigure

    Ummmm… once you’re talking about bikes that get 20mpg, you’re typically looking at a mileage discount in the car’s favor. Unless your car is made by Kenworth.

  • Wereweazle

    That bike looks familiar…

    • noone1569

      You the man!

      • Wereweazle

        Go Baconpocket!

  • Groomez

    And this is why HellforLeather gets top honors in my book..

  • the_doctor

    …Then divide by 0 and… Uhoh.

    • mugget

      Damn you, dammit! You just broke the universe!!

  • R.Sallee

    At one point I convinced myself I was saving money by riding the bike instead of the car–averaging around 50 mpg versus 17 in the ol’ Goat. But then I started doing regular maintenance, replacing tires and brake pads at 3x the frequency of car stuff. If I had garage space to do my own valve maintenance I could probably make riding economical, but I wouldn’t sell someone on riding on the basis that they’ll save money.

  • slowestGSXRever

    I prefer to think of it in terms of the money I save from leaving my car home:

    1996 Subaru Imprezza = 22 mpg
    2001 Ninja 250 = 60 mpg

    Gas prices @ about 4 bucks
    1000 miles traveled in my car = $181.82
    1000 miles traveled on a ninja = $66.67

    Put almost 2.5k on the ninja since the beginning of the year, so I saved myself $287.88, woo! Time to blow it all on beer and hamburgers!

  • noone1569

    I plugged in my XB12R (~50 mpg) vs my WRX (~17 mpg city) and I’ve already reached the payoff!! FTW

  • Brammofan

    Can’t wait to figure this out with my Honda Pilot (19 mpg) and my Enertia.

    • Wes Siler

      Let us know how that goes and I’ll put it in the article.

      • nick2ny

        If you’re claiming the bike has no energy cost, neglect everything after the minus sign.

        BP/(G/CF) = miles

        $7k/(($3.50/gal)/19mpg) = 38,000 miles.

        The trouble is that once you’re using gas at less than about a quarter the rate of the car, any increase in bike fuel economy has a rapidly diminishing effect on the payoff mileage. So your bike has a payoff of 38,000 miles, but if it got 80mpg the payoff would be 49,836 miles… If it got 35mpg it would be 83,125 miles (all assuming $7k bike and $3.5 gas).

        Once you’re using barely any gas, boosting economy to using no gas at all isn’t a massive help. You’re better off buying a car that leaks gas and gets 4mpg if you want to lower the payoff mileage (as long as the car leaks gas only when it’s running!), because as you can see, you’re pinned at 38,000 miles when you’re using no gas whatsoever.

        • Brammofan

          I think Ben’s and RSallee’s points about maintenance costs should come into play in the equation somewhere. My maintenance costs are basically confined to chain lube. Eventually, I’ll have to replace tires and chain, but that’s about it. There’s an advantage to few moving parts.
          And no, I never said I had no energy costs. It costs me approximately one cent per mile based on my electric rates.

          • nick2ny

            Years of battery life and cost? Not giving you a hard time, just curious.

            • Brammofan

              The specs say 2,000 charge cycles to 80%. On the forum, one of the Brammo people said this:
              Remember – when your Enertia batteries hit 2,000 full cycles they don’t just drop dead. They will have been sliding gracefully towards 80% of their original capacity over 2000 cycles. So here are your choices at that point:
              • Do nothing the bike works just fine and you are totally happy.
              • Replace with original specification Valence batteries.
              • Install a different “go farther” battery set supplied by Brammo.
              • Install a different “go farther” battery set supplied by a third party.
              • Sell your iconic Enertia on e-Bay (did Brian name that too?) for $50k buy a brand new Brammo and put the rest in your 401K.

              I have no idea about replacement battery costs. Hopefully, by the time I have to replace them, they’ll be the size of watch batteries and cost the same.

          • Ben

            Here’s a graph I did a while back that takes maintenance and service life into consideration…


        • Dan

          Bingo. Especially as average car efficiency gets higher, MPG becomes less and less helpful to consumers trying to cross-shop unless youre really good at mental math. A better metric is gallons per 100 miles – because at least that is linear in dollars, which is probably the only dimension anyone cares about.

          I think somewhere in the small print of those EPA printouts on new cars is an “estimated annual fuel cost” made using the gallons/mile number and optimistic assumptions about miles/year and dollars/gallon, but i dont know anyone who really looks twice at it.

          • BMW11GS

            i do!

  • Ben

    Highly dependent on the bike… After figuring in purchase price (over expected lifespan), tires, oil changes, chain and sprockets, valve adjustments, etc… My KTM 950SE costs about the same to drive per mile as my Full size pick-up truck– About $0.40 per mile. My 1990 dr350s which I picked up for $500 only costs about $0.13 per mile though.

    • nick2ny

      With a full size pickup truck you can “pick up” an RC45 for free using this equation

  • nick2ny

    Also, the real time to persuade people to buy motorcycles is when they’re coming up to lease mileage limits. It’s cake.

  • dux

    And the biggest discount? Not buying a car at all.

    • nick2ny

      Winnar! I’m flogging my miata this month and picking up a nice, miata-y DR350 instead…

      • dux

        My 93 dirt-version DR did me well. Didn’t need a key, either!

  • Ceolwulf

    Excludes insurance; which here in Manitoba means you have to save an additional $1000 up to $3000 per year. Also doesn’t account for anyplace that has a non-riding season, so here those savings have to take place in about six months. In other words, never going to happen.

    • dux

      Poor, poor Canada. It’s not a real country anyways.

      • Ken

        at least we don’t have to worry about going bankrupt if we have an off :P

  • Sam

    I call BS. I made this type of rationalization when purchasing my first bike six years ago. I now have four bikes in my garage, done countless track days, and club raced two full seasons. Those fuckers aren’t nor is my addiction paying for shit!

    • Roman

      This is exactly what I was thinking. The formula assumes you have the willpower of a monk. Most of us get a new bike at least every 2 years if not more often. We see new kit we wanna get, cool little mods, trackdays and all the gear that requires, etc…. Biking is an awesome hobby, tons of fun, but unless you’re getting around on a 5-year old VStrom 650 as your only ride, it’s not fucking cheap.

      That said, I’m getting rid of my car and only getting around by bike starting this year (assuming car sells…anyone want a Mazdaspeed Protege?). So we’ll see. Living in the city helps though, not sure I’d get away with it in the burbs.

      • noone1569

        This is what I am considering. Drop the WRX . . . buy a nice WR250 or similar for the shitty weather days.

        Who wants a 2007 WRX

    • nick2ny

      Maybe you need a car with worse gas mileage?

  • Tony T.

    Compared to the V6 ranger I was borrowing before the bike came along, it will only take the bike 3,000 miles to make up the difference. At the rate I’ve been riding the bike will pay for itself at least three times over during the course of the year (not including cheap-ass tires and upgraded gear for the wet months). I think I can live with that!

  • Devin

    Whoever formatted the first paragraph is an asshole. I totally thought this was an incognito release notice for tha Hooligun and got all excited.

  • Roland

    I had a CM400T once, couldn’t feel anything south of my wrists after an hour, just sayin’

  • Joe

    If you ever find yourself using an equation to explain the appeal of motorcycles, I would say you’ve already failed. Riding is about fun and feeling free and alive! I’d say that’s the greatest payoff ever.

  • oldblue

    I’m with Joe.
    The sort of people who would come across to bikes because of a cost-of-running equation are the same sort of people who get flu shots and hide under a table screaming when a small bird flies into an open air cafe. In their minds, the danger factor (the one we see as excitement) will negate the economy factor.

    But 10 points for trying!


    • Devin

      It could also be the lame ass excuse it takes to convince their wife a motorcycle is a good idea.

      • Joe

        So true (unfortunately). Get a new wife.

  • pplassm

    Wow. Your R1 only gets 20 MPG? I get 45 commuting on my Speed Triple, and i’m not going slow!

  • Krisa

    My Bonneville will pay for itself in just over 400,000 miles. (My other vehicle is a Honda Fit.) Kinda wish I hadn’t calculated that one out.