Saturday, June 9, 2012

Moto-Math

I am continually self-amused by the variety of topics that cross my "inner visor" while riding, especially while commuting since this well-traveled Interstate slab is made for daydreaming.  

The inner conversation can be anything and everything and often, that's exactly what it is... a constant stream of cerebro-babble.  But then, just as often, something of substance dances across my brain waves. 

One constant source of entertainment is the dashboard of my BMW RT.  In addition to standard data such as speed, engine rpm, ambient temperature, total miles, trip miles, time of day, etc., with the BMW you also get suspension set-up indicators (with on the fly adjustment capability), heated grip indicators, heated seat indicator, as on-board computer outputs of miles per gallon, average miles per hour, and distance remaining on available fuel - And there in lies the fun!

Moto-Math
It is these last few computational features that stimulates that part of my brain that can sometimes obsess over numbers and calculations.

Some background is in order... My career has been such that I have dabbled in numbers for the last 40 years in one way or another.  At the zenith of my research career it was all about calculating the thermodynamics of molecular interactions; today, the calculations are more about academic unit costs, student credt hour generation, revenue streams, and projecting budget trends.

But, back in the day, my research often had me using ultra-speed centrifuges, those household washing machine-sized instruments capable attaining sufficient g-force to physically sediment macromolecuales, usually DNA and protein.

Since I love all things that move (!!), I was thrilled to use these incredible machines that will spin a 20 pound titanium rotor at speed of 60,000+ rpm.

SW Ti-41 Rotor

Typical Swinging Bucket Rotor Application

Maintenance schedules for these delicate machines track total revolutions rather than hours of operation, or as in a motor vehicle, miles ridden. This mode of service tracking seems a bit foreign to internal combustion engines, but quite frankly, it should not.  In fact, I would argue, ALL motors that perform rotational work should have maintenance schedules that track total revolutions rather than miles, as is the case of motorcycles and automobiles.  Doesn't it make more sense that the lifetime, or the maintenance schedule for a motor center on the number of times it completes its work cycle rather than how far it propelled the object that it sits in?


My motor of choice: The BMW 1200 CC Boxer twin!

This (finally) brings us to Moto-Math!  Checking my dash while riding I notice that my average miles per hour (for the entire lifetime of my bike since I have never reset this function) is 47.8.  Now, this fluctuates a bit depending upon whether I am on a trip of do lots of in-town riding.  But 47.8 is a good place to start.
  • Couple my average miles per hour with the total number of miles ridden (31,175) and you easily determine that I have ridden my 2012 BMW R1200RT for 652.2 hours. 
  • In 4th gear I am traveling 48 miles per hour at 3200 rpm (my overall average speed).
  • 3200 rpm x 60 minutes per hour = 192,000 revolutions per hour (rph)
  • 192,000 rph x 652.2 hr ridden = 125,222,400 total revolution
  • With 6000 mile service intervals (recommended), my bike has spanned 5.2 service intervals
  •  A revolutions-based service interval would thus be: 125,222,400/5.2 = 24,081,231 
  • Therefore: 25,000,000 (25 M) revolutions would be the revolutions-based service interval (RBSI)
Now, we simply need to entice BMW to install an RBSI indicator function on-board computer!  I'm sure they will get right on this! :-)   If anything, the Germans like numbers, no?!!

A few more things to consider.... I've been on my bike for 652.2 hours over the last 28 months of ownership.
  • 652.2 hours = 27.18 days of riding 24 hours a day!  Almost a month of 24 hour days!
  • Or... 81.5 eight-hour days in 28 months (~820 days)
  •  81.5 riding days/820 total days = 9.9%
  • Therefore ~10%  of my total daytime activity over the span of 28 months has been riding! Sweet!!

What do I have to show for all that riding time:
    • 4 sets of tires
    • 6 fluid changes (oil, gear, & rear-end)
    • Two flat tires  :-((
    • 13 states visited
    • Immense joy, pleasure, relaxation, reflection, excitement, and adventure!
    • and... Significant improvement in my cognitive capacity!!*

Not to mention an improvement in my capacity to do math in my head while riding!!


-LD