Issue link: http://read.dmtmag.com/i/34501
REGROOVING Only MICHELIN truck tires that are marked ® “REGROOVABLE” on the sidewall may be regrooved. After regrooving, you must have at least 3⁄32" of under tread covering the top ply. If steel is exposed, the tire must be scrapped or retreaded. In addition, some tread designs will have a regrooving depth indicator as shown below. Do not regroove below the depth of the indicator. Regrooving depth indicators are holes (of 4 mm depth) situated on the treadwear indicator to indicate the recommended regrooving depth for these tires. It is the responsibility of the regroover to assure that all Federal Regulations are met. See US Code of Federal Regulations: Title 49, Transportation; Parts 569 and 393.75. One of the regulations governing regrooving tires requires that a regrooved tire must have a minimum of 90 linear inches of tread edge per linear foot of the circumference. The MICHELIN XZU2 tire has only 3 circumferential tread grooves. To meet the 569.7 (iii) requirement, additional lateral grooves must be added as shown below. New Used Regrooved 1.6 mm Depth Indicators 1.6 mm = 2/32nds 4.0 mm = 5/32nds 4.0 mm Section Nine: Appendix 139