3DBikeFit.com — What Changed?

2012-11-23 • SEND FEEDBACK •
Related: 3DBikeFit.com, bike fit, training

The 3DBikeFit.com changes were really interesting— once I “dropped into” the right position, I could immediately feel an easier and more powerful spin. It was not subtle.

A physical assessment showed promise for potential adjustments (no limitations):

• Left/right leg length identical.
• Excellent hamstring flexibility.
• Excellent pelvic rotation.
• Slightly tight gluteal muscles (no big deal, addressable via stretching).
• No injuries.

Here’s a summary of what changed at first on the bike:

• The seat I was using was not conducive to pelvic rotation, needed for a straight (not hunched or curved) back for maximal power transfer.
• The seat was too narrow, causing a non-centered position on the bike (“windswept” riding position).
• A new seat was installed nominally at the same height, but actually different because of the seat shape.
• The seat moved forward a good amount.
• A 120mm stem (up from 90mm) was put into place.
• Foot support was not working well. Foot support with an excellent heel support was installed. Much better support than the stock inserts (or the eSoles I had tried earlier in the year).

At this point, I “dropped into” a position where the easier and more powerful spin became evident to the point of me feeling really enthusiastic as the changes became manifest.

My back was more or less straight (instead of being hunched), my arms and shoulders and head relaxed out of a extended semi-locked position, and the smoothness of my pedal stroke improved audibly and in terms of perceived effort.

Next, fine-tuning stage:

• The seat position was adjusted in small increments, using side-by-side videos to analyze heel/ankle and knee motion. The final adjustment on fore/aft seat position quieted down useless motion, so that what was left was mostly a smooth pedal stroke.
• Cleat position was biased on the right side to offset the asymmetric crankset offset (not unusual on many bikes); this improved centering of the knee tracking, making it more symmetric left/right.
• Left/right pedal offset from center was determined to be a little tight (I believe this is Q Factor). Using 2mm pedal spacers was too much, 0mm was slightly tight, 1mm worked out just right.

Not short or simple!

This all might sound simple enough, but in my case, the entire process from start to finish took a long afternoon (5+ hours, made longer by my inquisitive questions). It was a long day, but the results were worth it.