Effect of 90 degree head angle (vertical steering axis) - zero flop

Question

Are there any two-wheel bicycles with 90 degree head angle? The trail would be determined by fork offset alone, i.e. it would be a caster wheel.

Related:

• What effect does head tube angle have on a bicycle?
• Desirable maximum steering angle

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• Adjustable Geometry Bike

  • Photos
  • Interview
  • Results?

• https://www.bikeradar.com/news/this-part-wooden-enduro-bike-features-an-adjustable-head-angle/

  • Results?

• https://moorepants.github.io/dissertation/parameterstudy.html#geometric-variation

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• Handling Stability Parameters
• Understanding the bike geometry through riding
• What makes a bike stay upright when moving?

The first bicycles (velocipede/penny-farthing) had a steep steering angle: https://en.wikipedia.org/wiki/Bicycle#/media/File:Michauxjun.jpg

Video: How to ride a penny-farthing