Bike Info

Bicycle Frame Geometry 101

I was discussing frame geometry with a prominent coach last week and his perspective on frame geometry struck a nerve with me so I wanted to share this topic with you.

I had been riding “stock” frame geometry for decades and the possibilities created by the combination of an unlimited fitting system and true custom geometry did not exist for me, and thus for you, until fairly recently. The time honored principles of Knee Over Pedal Spindle, (KOPS), the Lemond method, standover height, saddle height equal to hip height when standing next to the bike and scads of other techniques were developed to help people choose a bike size that would work for them.

We need to look at a bit of history because bikes were made quite differently in the 1970’s and before than they are today. The ’70’s were a time where road bikes had a much different geometry, with seat angles in the 71-72 degree range. Additionally these bikes were built in half sizes and thus had as many as 12 sizes for one model! Today’s bikes have between 3 and 5 sizes so more people are forced to “fit” a bike that will be less than perfect.