Software, Trails to ride, photos & trail maps for Mountain Biking ( MTB ), Touring,  & Cycling, bike trails in utah,  rides, links & bike manufacturers

Calculator v3.0

This is also available here in spreadsheet form!!

Independent Ride Variables
Estimated VO2 Max 60 is good
Lung Capacity in liters 5 is average
Bike Weight (lb.) Bike and equipment.
Body Weight (lb.) Everything else...
Total Time for the Ride (in minutes)
Elevation Gained (total) (feet)
Elevation Lost (total)
Net Headwind (in MPH)
Chain Lube Condition? Transmission efficiency, .95 is best
Tire Pressure - psi (for rear if different)
Position .6=upright to .3= full tuck
Surface condition (1.0 to 3.0) See below...
Clothing .9=smooth racing tights to 1+=baggy attire
Tire Type .015=knobby to .005=slicks


  1. Enter your lung capacity in liters. Calculate by blowing up a balloon or displacing water in a container. (Or estimate, huge lungs are~7, small people~4)
  2. Calculate your VO2 maximum (if you don't know it) by filling out a page for your best aerobic ride, preferably a hill climb over 1/2 hour, as these are likely to be more accurate. Use the resulting figure , this will be a benchmark for you.
  3. Enter the distance of the ride.
  4. Weight of your machine, water etc.
  5. Weight of you, clothes, Camelback, etc.
  6. Elevation gained.  Total of all up-hills during the ride.
  7. Elevation lost.  Total of all declines.
  8. Enter your chain condition.  New, well oiled chain and gears give an efficiency of ~95%. Dry, dirty chain and cogs can drop below 90%.
  9. Tire type.  A fat knobby 2.25 is about .015, the best road tubulars about .002! My 1.9 touring tire = ~.006. I am doing some more experiments with large factor tires, and will include them in future updates.
  10. Enter your rear tire pressure, as 70% of your weight is there.
  11. Enter your normal position, frontal area depends mainly on this, .33 for track racers, .5 for upright, .55 when honking.
  12. Enter the total time you ride, include brief stops.
  13. Enter the surface condition. This is the road surface factor. I.e., the number of times more resistive a surface is than smooth concrete

    Smooth pavement= 1.0 Rough pavement= 1.1 - 1.3
    Dry, hard dirt or cinder= 1.3 - 1.6 Deep, dry sand= 6+
    Wet, firm cinder/sand= 2.0 - 3.0 Deep mud= 5+

  14. Enter your Cd, loose shirts/jackets add at least 10% over tight jerseys!
  15. Hit the CALCULATE button for the results. Use <alt>+< or the back button to return.

Note: I would greatly appreciate feedback on people's results!

E-mail me at: rays aaat (<- anti-spam version) Thanks!


More to come!
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