How to extract values from pandas Series without index

Simply use Series.reset_index and Series.to_frame:

df = speed_tf.reset_index(drop=True).to_frame()

Result:

# print(df)

   Speed
0  -24.4
1  -12.2
2  -12.2
3  -12.2
4  -12.2

speed_tf.values 

Should do what you want.