Spiral Curve Turn

I have laid out and/or built and experienced my share of circular turns, but also spiral and logarithmic. Recently I built a spiral 180 based on the Golden Ratio or Fibonacci sequence. More on turns here.

First, I’ll say that I am a skeptic, but thought it would be fun to experience the Golden Ratio on a bike. Why not? Second, there is a lot of bs and “woo” surrounding the golden ratio, but this video helps put some of it to rest:

Anyway, here it is, two connected circular radii (some of the comments are worth noting):

For those of you not on Instagram:

Fibonacci_spiral_turn
You will have to go to Instagram to see the dirt photos, or ride it in person on the Augusta Mine Trail.

One of the main things doing the spiral layout did at was help squish or flatten the depth of the turn to help it fit against the big rocks behind it, but still give it the same entry and exit. It rides and runs nice, but I wouldn’t say there is anything magical or special about it, it’s just one outcome of the myriad of possible curved/arced insloped turns.

pump-track-berms-paths
We do turn in perfect circles, but quite often deform the circle by drifting a little out of round or cutting the turn as we like into various spiral path possibilities…but there is indeed a speed specific sweet spot and deformity for most riders in a particular speed range (and wheelbase perhaps).

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