The timers setting will change the speed(rpm), if you trim the prop the timer still tells the esc how fast to spin the motor. Trimming the prop will give more ground clearance, less load and less thrust. Shorten the lines and you pick up a faster lap time.
Bob

If you cut prop tips, you will unload motor, and you will reach higher RPM, but it does not work like IC engine. If you unload IC engine, you will get more power (at RPM we fly - means not limited by engine ability) ... while unloaded electric motor does provide LESS power. Means it is hard to expect that smaller prop with lower efficiency on motor with less power can handle model at higher speed. Prop will simply work at higher slippage what will result in slower lap time. So you need to do just opposite. My experience says that if I use 12" prop instead of 11" I can reach higher speed and shorter lap times.

However as Howard wrote, more pitch is trivial solution.

Hi Larry,
You cannot trim the prop tips to get a little more speed.
Any (small) RPM gain will go hand in hand with a small loss in airspeed.
If you're going to fly faster, you will need to consume more power, not less.

take care,
  Dean P.