Effect of air density on speeds

[quid]

Vr (min) is driven by 1.05 Vmca or 1.10 Vmu. If Vmca is reduced, Vr may be also.

V2 is driven by 1.2 Vs or 1.15 (?) Vmca. V2 (min) will reduce (at increasing density altitudes) until is reaches the 1.2 Vs value, and then will remain at that IAS.