Please note that these pegs can unscrew, therefore if they are not tightened properly vibration can cause you to lose a peg.
After you install the peg take a towel and wrap it around the peg, then take a wrench and clamp the peg down tight.  Do be careful as you can scratch the peg, be sure to have plenty of material between the peg and wrench to protect it.  This is sufficient to prevent the peg from unscrewing, however a thread locker is also recommended.