Originally Posted by
VforVendetta
If you haven't selected the correct autobrakes setting, have floated, etc, yes you have to disconnect the autobrakes early to let it roll or apply manual braking early to increase the deceleration to vacate as planned. Autobrakes disconnect as soon as you've matched the braking pressure applied by the system. There's only a spike if you misjudge and apply more pressure, let go rapidly as autobrakes disengages etc. If that happens to you you should tighten up your skill doing it. Apply pressure gradually until disconnection, then gradually increase or decrease as needed and there won't be a jolt. It's not that hard.
I believe that it is a common misperception that you need to OVERRIDE the current brake pressure. I asked a mechanic at my airline, and he showed me in the Boeing repair manual that it took 1,000-1,200 psi of hydraulic pressure from the brake pedals to disengauge the autobrakes, no matter what the autobrake setting is. Interestingly, I also was taught in ground school and also on IOE that you had to override the autobrakes. Have you ever found that you had been taught wrong? Try this with auto brakes 3 or higher, and I bet that you will be surprised at how little pressure it takes.
This was on the 737-300, (mumble) years ago, so I agree that the design may have changed. I just don't think so.