Yes, you can shorten the length ofyour drink tube. Depending on the model of your hydration reservoir, you simply trim the tube down to the desired length.
If you have a Big Zip™ EVO or Hoser™, trim the tube from the end with the bite valve. For the Big Zip EVO, simply remove the shut-off valve, trim to the desired length, and re-insert the shut-off valve. For the Hoser, remove the bite valve, trim to the desired length, and re-insert the bite valve.