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Comment by RhysU | Hacker News Reader

Capability is a poor metric.

Bicycles go downhill real damn fast. The top speed of a bicycle is largely limited by how foolish the person atop it is and the local geography.

Bicycles can be geared to go across the salt flats real damn fast. The top speed of a bicycle is largely limited by how foolish the person atop it is and the local geography.

Bicycles, even without crazy geography or gearing, can be ridden real damn fast by professionals. The top speed of a bicycle is largely limited by how well-trained the person atop it is. Says Wikipedia:

> The 2025 edition was the fastest Tour de France in history. Tadej Pogačar rode 3,298.6 km in 76h 00m 32s, thus realising an overall speed of 43.4 km/h or 27.0 mph.

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Anything on wheels is going to go downhill real fast. Terminal velocity under gravity is not what we use for classifying vehicles because it doesn't serve as a useful bucket because it's not a feature of the average mechanism of propulsion. And that's the part we care about. The presence of top athletes doesn't change the average users experience of the vehicle.

Typical bicycle geometry is just tire limited in it's high speed cornering performance; a 4-wheel car with a center of mass relative to size anywhere near as high would just fall over before really hitting tire limits.

Coasting down switch-backs at whatever speed the car traffic on the road feels like, and not giving any car incentive to overtake by matching the speeds.

So, if I put a pro rider on a bicycle you're cool with me having them scream around crowded areas?

Traffic regulations are fundamentally about tail events. Most of the time, vehicular traffic is boring.

The right metric is kinetic energy. But, it'd be unpopular for speed limits to depend upon vehicle mass. Or, in the case of bicycles vehicle and rider mass since the rider mass isn't negligible.

Reckless endangerment covers the case of pro-riders being idiots. Classification of the vehicle should rely on the vehicle's properties instead of the operators capabilities.

> Reckless endangerment

So maybe we can enforce that part a little better.

If I tried to drive a car on pedestrian path at even 10kmh I'd be chased by police helicopter and appear on national news.

Agreed.

However, that shark is jumped as soon as the classification criteria involve operator-dependent properties like maximum speed of a bicycle. It has no operator-agnostic answer.

How fast can a normal person riding a normal-style bike with modified gears go across the salt flats?

I feel like it's obvious that capability would be measured with a fixed level of user input on a fixed course/dynamo.

2018 had one pro rider do 183 MPH per https://www.bikeradar.com/news/cycling-land-speed-record-sma...

I'd wager most weekend spandex warriors could break 100 MPH peak.

When you're drafting a dragster so close you're partly inside it I'm going to go ahead and say that doesn't count for my question.

Certainly crazy circumstances. But, it's just a bicycle.

It's a bicycle that doesn't have to deal with air resistance, which sidesteps much of my question.

I am not 100% sure but I think Pogacar goes a little faster than the average cyclist.

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