how to change base speed in the middle of the race?

[weeg]

i made this really simple code that changes the base speed of the game if a flag is set. however, when the code gets executed, the speedometer still shows the old speed (speedometer shows 84.01 as max non-wheelie speed before the code is executed on funky flame, same after it gets executed) but if i respawn, speedometer shows 84.85 (updated speed) as the max non-wheelie speed. i tried to run some function in hope that the speedometer would show the updated speed (0x80574304, aka the updateVehicleSpeed function), but the game would just crash.

Code:

#To be inserted at 80571CA4
head:
  lis r11, 0x8000
  lbz r10, 0x1d0(r11)
  cmpwi r10, 1

  beq set
  b not


set:
  lis r12, 0x42b4 #r12=90 in float
  stw r12, 24(r3)
  b def

not:
  lis r12, 0x42a8 #r12=84 in float

def:
  lfs f1, 24(r3) #default instruction