Issue link: https://read.dmtmag.com/i/34500
TREAD DEPTH PULL POINTS When setting a fleet standard for tread depth pull points, there is more to consider than just the legal DOT (Department of Transportation) minimum tread depths of 4⁄32" steer and 2⁄32" drive and trailer. Most fleets who retread, or even sell their casings to dealers or other fleets who do retread, will generally choose a tread depth of 5⁄32" or greater to help ensure that the casing has the best chance of passing inspection. One reason they choose this higher than legal minimum depth is that they know that even if they set it at 5⁄32" there will be some tires that slip through, and may not be removed until 2⁄32" or 3⁄32" later. In other words, if a tire that should be pulled for fleet spec of 5⁄32" stays in service a little longer, it won’t be as big an issue as the tire that was supposed to be pulled at 3⁄32" and continued to stay in service for an additional 2⁄32" of wear. It is a good safety net for ensuring you meet DOT minimum requirements, and also for the casing that becomes more susceptible to stone drilling, penetrations or cuts. Additionally, there are also some visual clues that are molded into every MICHELIN to pull points. ® X One tire to alert you ® Shoulder Scallops indicators that it is legally time to pull a drive or trailer tire. Care should be taken to not take tread depth measurements at the wear bars. Their placement is indicated on the sidewall/shoulder by a miniature Michelin Man. Don’t Measure Tread Depth Here Michelin Man Sidewall Indicator In order to fight irregular and fast wear, traditional dual tires need to be matched within 4⁄32" tread depth or 1⁄4" in diameter and within 10 psi. MICHELIN ® X One tires remove this extra ® maintenance burden. However, all tires (dual or wide single) should be within 4⁄32" intra-axle (across the axle) and inter-axle (axle to axle groupings) for proper engine and braking functions and to reduce wear and tear on axle differentials. Finally, some fleets find that it may be better to pull drive tires at around 10⁄32" and move to a trailer position. If you are running in mud, snow, or other low traction situations, this may be a great way to address traction concerns. Experience shows that worn drive tires perform exceedingly well in trailer positions. Mold Line All MICHELIN X One tires have built-in “scallops” ® ® or small indentations right on the shoulder edge. The bottom of this scallop corresponds with the normal wearing surface of the tread. Therefore, when you wear down to the bottom of this indentation, it is time to remove the tire for retreading. Additionally, there is a circumferential raised line just below the bottom of the scallops. This is where the tread mold meets the sidewall mold, and the rule of thumb if using this indicator as a reference is to pull the tire when the wear reaches 1⁄4" ABOVE this line. Also, there are 2⁄32" wear bars molded into the tread on all MICHELIN X One tires. When these become level with the tread, they are visual ® ® 50 MICHELIN X One Tire Maintenance ® ® Within 4⁄32nds Within 4⁄32nds