[freebeard]

The Mk III at least was sensitive to tyres and did not always react as you would expect to a change of rubber. Indeed it was sometimes counter-intuitive; for example, increasing tyre pressures on some tyres gave better grip in the wet on sprint & hillclimb competitions.

First two from DuckDuckGo:

Originally Posted by DDG

Hydroplaning: What it is and how to avoid it
https://www.msn.com/en-us/autos/owne...it/ar-BB1dLqJV
Tire pressure is one of the leading causes of hydroplaning because it impacts how much contact your tires have with the road. When tires are under-inflated, they are less likely to grip and hold...

How does tire pressure affect susceptility to hydroplane ...
https://mechanics.stackexchange.com/...-to-hydroplane
Clearly, the lower the tire pressure the more likely a tire is to hydroplane. There are two main reasons for this A tire with lower inflation pressure has more contact area, and it, therefore, takes less pressure to lift the tire off the pavement. A tire with lower inflation pressure presents a slightly concave profile to the pavement.