Heavy cavalry charge:How exactly was it done?

[Sean Manning]

Kineas, I'm skeptical of attempts to use 18th-19th century evidence to understand what earlier cavalry could and couldn't do .. at least without a heavy infusion of ancient/medieval sources. Such late cavalry fought in shallow formations, and faced gunpowder weapons which were quite effective at killing and disordering them. The point about cavalry being of limited use against a steady hedge of spears unless they can frighten it into breaking is a good one, but that's what cavalry are supposed to do! And medieval cavalry don't seem to have always recoiled from spearmen/pikemen without contact like Napoleonic cavalry generally did. They usually lost that fight, but it took some time.

One day I'd like to see a dedicated study of the mechanics of heavy infantry/shock cavalry combat based on (eg.) medieval European sources. The cavalry normally lost in any period, but how did it happen?