Originally Posted by
zonatandem
Have actually run the cables inside the handlebar on one of our tandems.
Drilled hole about 1 inch from bar end and another hole where bartape ends topwards the stem.
Was told that handlebar would eventually break where we drilled it.
Lasted 56,000 miles, and no issues.
Your results may vary.
With heavy wall aluminum bars I suppose this is ok but certainly not recommended and particularly not a good idea with thin wall, lightweight aluminum or cabon bars.