In a post at http://www.msgroup.org/forums/mtt/t...IC_ID=13143& my attention was called to tip #112. A tubeless tire is held in place by seating the bead in the rim channel. Once the bead is seated, It isn't coming off without deflating the tire and using some sort of bead breaker tool to get the bead out of the channel. The need to break in street tires comes from the mold release agent on the outside of the tire needed to remove the tire from the mold as well as the tire being too smooth. Trying to scuff up a new tire manually mostly spreads the mold release agent around the tire so is ineffective at making a new tire safe. Miles of travel are needed to get the agent off of the tire and distributed onto too many miles of roadway to be a danger.
While the tire does grow when heated, that growth is mostly where the heat is, at the tread more than the wheel rim. What heat is present in the tire bead is also at the wheel rim so the two will both grow and stay together. There may be some difference between the alloy wheel and the steel beads but the alloy will grow more and tighten the bond. There was a time early in the development of tubeless motorcycle tires that cast wheels without bead channels were available. These took some time for the pressure of the tire bead to cause a more secure attachment. Even then it was dangerous to use tubeless tires on wheels not having a bead channel.
Today's tubeless tires and bead channeled wheels are not going to separate from the wheel no matter how enthusiastically the machine is leaned into a curve. New tires and even well broken in tires that are cold at the beginning of a ride will slide out more easily though. The tip doesn't mention the difference between tubed and tubeless tires. Even if it was possible to break the bead of a tubed tire, it would not lose air unless the tire rotated on the rim enough to break the valve stem. While the advice in the tip is important and ought to be followed, I have issues the reason for the advice and consequences for not following it.
Safety tip #112
Moderator
Posted - 04/14/2011 : 5:06 PM
