Cloud Cutter
I haven’t flown the B747-400 or the B777 but I have just looked up the relevant section of their FCOM 1’s and nowhere does it refer to the wheels having to spin up before the Ground Spoilers deploy. Maybe it is just a B727 thing or something? It make far more sense to me to have the Ground Spoilers deploy on a squat switch or reverse thrust when you are aquaplaning than on tire spin up which make not occur until you are off the far end of the runway.
Ground Spoilers B747-400 (FCOM 1)
On the ground, the Speedbrake lever stop retracts allowing the Speedbrake lever to be moved fully aft to UP position. All six spoiler panels on each wing extend to their full travel positions.
When the Speedbrake lever is in ARMED position, thrust levers 1 and 3 are near the closed position, and the main landing gear touch down, the Speedbrake lever is driven to UP position, extending all spoiler panels. If the Speedbrake lever is in DN position with the main gear on the ground and thrust levers 1 and 3 near the closed position, and reverse thrust levers 2 or 4 are pulled up to idle detent, the Speedbrake lever is raised out of DN detent and driven to UP position. This provides an automatic ground spoiler function for RTO and provides a backup automatic ground spoiler function for landing when the Speedbrake lever is not armed during approach.
Spoiler Speedbrake Operation B777 (FCOM 1)
In the ARMED position, the speedbrake lever is driven aft to the UP position when the landing gear is fully on the ground (not tilted) and the thrust levers are at idle.
The EICAS memo message SPEEDBRAKE ARMED is displayed when the speedbrake lever is armed.