Do you know the ply of your tires? Apparently, it makes a significant difference in hydroplaning speed. The formulas mentioned above were developed by NASA on tests of bias ply tires. Radial ply and H-type tires have lower hydroplaning speeds. The formula may not be applicable to you.
“Recent studies into the critical hydroplaning speed were conducted by the National Aerospace Laboratory (NLR) in the Netherlands. “These studies were considered necessary as the data that was compiled by NASA was ageing and need to be revised to conform to modern new tyre types that were introduced for civil aircraft. The following three tyre types were considered;
bias-ply; radial belted tyre, and; the type-H tyres.
It was concluded from the analysis that the radial-belted and type-H tyres had a significant lower hydroplaning speed than the bias-ply tyre. This was caused by the difference in tyre footprint characteristics of these tyres.”
Below, a link to tire construction....
https://www.aviationhunt.com/aircraf...-vs-bias-tyre/