I know that. MY point was that if I'm not able to lock the brakes, I don't know if they are working to their full potential. If I could lock them, I'd know where that point of lock up is and brake up to just below that point.
Think of it like a throttle cable that isn't adjusted to allow full carburetor throttle blade opening. You could be driving around with a maximum of 3/4 throttle and not making the most power available.