see also: archived feature request: Braking/speed limiting in corners. This is very similar but with additional detail.
The Dolphin City crit course highlights a limitation of the bike model: that there is no slowing in corners. This is a critical part of actual crit racing, and a motivation to be at the front of a pack going into corners.
The lateral force on a bike when cornering is proportional to v²/R, where R is the cornering radius of the center of mass. Since it could well be assumed that this is limited by traction, and since there is no crashing in Zwift that riders brake to avoid exceeding the traction limit, in corners of local cornering radius R, the bike speed should be limited to sqrt( R A ), where A is the maximal transverse acceleration at the traction limit. I’m not sure what this is but any reasonable approximation should work.
The effect of this will be the following:
- pedaling power in excess of the power needed to reach this speed is wasted.
- coming out of a corner, power goes into re-accelerating the bike, in addition to maintaining speed.
- As packs reduce speeds going into corners, collision avoidance will force riders near the back of the pack to slow more than riders near the front, allowing the lead riders go maintain more speed thru the corner at the same average power than riders near the back. This will further provide a small advantage to breakaways, who will avoid this additional slowing. So bike speed would be reduced further if the traction limit for the corner would result in colliding with the rider ahead.
At present, corners are little more than decoration: it’s full gas, all the time. “Super-tuck” provides a reason to pedal less, on straight downhills. This would provide a further tactical aspect to power, reducing power going into a corner, and increasing it coming out of the corner.