Bike Hydration Configuration

If you’re reading this article, you probably train very hard to go fast.  Hard work brings speed, and there is no substitute for hard work.  In addition to hard work, you can gain speed by optimizing your bike’s hydration configuration. This is the first article in a short series on how to configure a fast bike.

The main impediment to bike speed is wind resistance.  Here are some tips for setting-up your bike’s bottle configuration:

  • Efficient bottle placement can save precious grams of aerodynamic drag.  Avoid placing bottles on the seat tube and down tube.  Although most bikes come equipped with hardware for mounting bottle cages on the seat tube and down tube, don’t take the bait.  Virtually all triathlon bikes have airfoil shaped tubes designed for aerodynamic efficiency.  By leaving these tubes bottle-free, you’re maintaining the aerodynamic integrity of your bike.  The most efficient bottle mounting location is between the aero bars (i.e., between your arms).  Several companies make aero bar bottle mounts (e.g., XLAB, Profile Design, etc.).  If you need more than one bottle, mount up to two additional bottles behind your seat.  Seat-mounting products are widely available (e.g., XLAB Wing, Shimano Aero Fuel, etc.), and they hide your bottles from the wind.   The efficiency of seat-mounted bottles depends on wind direction.  They are most efficient in a head wind.  The efficiency decreases as wind angle moves to a cross wind.  Therefore, when mounting bottles on your bike, mount the first bottle on your aero bars and additional bottles on your seat (behind you).


  • Avoid anything that alters the airfoil shape of your bike tubes.  Avoid attaching flat kits to airfoil-shaped seat tubes. Instead, stow your flat gear in a cylindrical container that fits neatly in a seat-mounted bottle cage.  As noted above, you have room for two seat-mounted bottles.  Utilize one cage for the cylindrical flat gear container, and the other for hydration.   Cylindrical flat gear containers are available from Specialized, XLAB, etc.
  • Avoid bulky hydration systems that alter your bike’s shape.  There are several systems that mount at various points in your bike’s tube triangle. Some sit in the “V” just above your cranks/pedals, while others sit in the “V” formed by the top tube and seat tube.  Wherever these bulky systems mount, they create significantly more drag than the configurations described above.
  • The configurations described above are best reserved for racing.  During training, you should mount bottle cages on the down tube and seat tube.  They are easy to reach and allow for up to five bottles – 1 aero bars, 2 seat-mounted, and 2 tube-mounted.  On long hot rides, take lots of water and stay hydrated!

If you’ve been racing with tube-mounted bottles, bulky hydration systems, and/or seat post mounted flat kits, these simple changes will significantly increase your bike’s aerodynamic efficiency.  With better efficiency, you’ll go faster.  For more ways to find free speed, subscribe to this blog.