posted
this went our our private website for our fleet today..but since were are all car nuts, i thought i would share it with yall. i know alot of your already know about this ...but some may not.
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A look into a “demon”: Tire Tread Separation
The year 2000 and 2001 fostered many a news story about “tread separations” of tires and SUV’s flipping over, people being severely injured or killed.
The truth is, tread separations are not nearly as common as you would think after hearing all these “stories”, and they are not always that dangerous either.
A “true” tread separation is when the tread delaminates from the belt package of the tire, causing the tread to “peel” off the tire. This can also occur in just sections of the tread surface as well. In this condition, the tire normally does not suffer sudden air loss (blow out). The air pressure will remain in the tire for quite some time; long after the vehicle is pulled over and stopped. The biggest danger in the “tread peel”, is that it can wrap itself around the axle or a steering component causing immediate loss of control.
Most of the time, the real culprit in tread separations is the belt package of the tire. Rarely does the tread separate just from “faulty” lamination to the tire. Passenger car tires are designed to deflect an average of 15 percent. The more the tire deflects, the more the belts in the belt package begin to try to “shear”. There are usually two or more belts in the belt package. These belts are primarily steel. When the tire flexes, if these belts start working against each other, you have “shearing”. If a tire is under inflated or overloaded, it will flex more, causing the shearing action to take place. This shearing action generates heat. If this heat continues to increase because of the energy coming in thru the deflection, it eventually leads to tire failure. That failure may be a tread separation, but most of the time, the belts separate from each other, causing the tire to “come apart” (blow out).
Check your inflation pressures regularly, and do visual inspections. Look for bulges on the crown edge (where the sidewall meets the tread surface). A bulge could indicate that the belt edge is beginning to separate. Look for strange premature wear patterns on the outside edge of the tread surface. This could indicate that that part of the tread is starting to “lift up” from the belt package and is wearing more rapidly. Also keep in mind; a misaligned front end will cause premature wear on the outside of the front tires tread as well.
The number one friend of the Tread Separation demon: ”Under inflation.” The second best friend is “Overloading”. Combine either of these, or both, with higher vehicle speeds and hotter ambient temperatures and the situation worsens.
Ken Collings Tire Program Coordinatior GSA Fleet Operations Division (703) xxx-xxxx Kenneth.collings@gsa.gov
-------------------- 1997 SLP Cars: Mine - Comp T/A #139 (sold and gone) Mine now - Firehawk #132 (For Sale - maybe, but maybe not......) 2003 Envoy - Loaded (hers) 2004 Envoy - Loaded (mine)
on high performance tires, H speed rating and above, the tire incorporates a nylon overlay to keep shearing from happening due the high speeds and g's the tire is subjected to in cornering... thats what makes our tires much mor exspensive than the normal passenger car tire. it also incorporates a nylon wedge in the junction of the belt package and sidewall to stabilize the belt package.
-------------------- 1997 SLP Cars: Mine - Comp T/A #139 (sold and gone) Mine now - Firehawk #132 (For Sale - maybe, but maybe not......) 2003 Envoy - Loaded (hers) 2004 Envoy - Loaded (mine)
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