Comment from Myth #4 Indoor Cycles require a lot of Fore/Aft Saddle adjustment to accommodate the range of cyclists coming into your class.

Well… the difference between real bikes and an IC bikes is that real bikes come in many frame sizes/geometries. They don”™t need much room for saddle fore/aft positioning because if you have the right size frame, you don”™t need that much fore/aft movement to find the right fit.

I should have anticipated this response and addressed it in my original post.

Changes in saddle Fore/Aft on an Indoor Cycle replicate the similar movement you would experience on various sizes of a typical road bicycle.

Let me explain...

I found this frame sizing chart at and it's typical of most any modern road bicycle frame design sold in stock sizes.

Areas in yellow don't change, regardless of frame size


Certain dimensions* at the rear of a bicycle do not change with frame size:

  1. Dimension [B] is Bottom Bracket Height = how far the horizontal center-line of the Bottom Bracket is off the ground.
  2. Chain Stay length [I] sets the distance the rear wheel axle is from the vertical center-line of the Bottom Bracket

Changes in frame sizes come primarily from:

  1. Seat Tube length [A] affects saddle / stand-over height and is the most common method of sizing bicycles
  2. Top Tube length [C] changes the reach to the handlebars.

So with the back of the bicycle essentially unchangeable, if you want to increase the frame size you're limited to; make it taller or longer... but only through increasing the length of the Top Tube.**

Notice that there's no dimension for Saddle Post position Fore/Aft. That's because it's controlled by the Seat Tube Angle [E] which is near universally @ ~ 73° plus/minus on Road Bikes.*** Lengthen the Seat Tube and Saddle Post naturally moves further behind the Bottom Bracket center-line.

Indoor Cycles use a similar Seat Tube Angle = similar results. Raising the saddle also moves it toward the rear ~ the same amount as you would experience with bicycle frames in various sizes.


*Yes, of course you can find examples in the extreme (very tall or short) where this isn't the case. I'm trying to make the point that bicycle manufacturers (indoor and out) design their products to fit 90+% of the general public, and, with over 100 years of experience, do so very effectively.

** Which is what Keiser attempts to do on the M3's handlebars. They move farther away, as you raise them up.

*** Triathlon Bikes for example, use a steeper (more vertical) Seat Tube Angle.


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