# US 2013/0153100 A1 · Tire with tread having improved wet traction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153100 A1 - Document ID: US20130153100A1 - Status: Published application - Kind: A1 - Application number: 13/713,762 - Filed: 2012-12-13 - Published: 2013-06-20 - Earliest claimed: 2011-12-14 - Inventors: Olivier Piffard; Cyril Guichon; Xavier Saintigny; Raymond Stubblefield - Web page: https://patentgrep.com/patent/US20130153100A1 ## CPC - B60C 11/11: in which the raised area of the pattern consists only of isolated elements, e.g. blocks (B60C11/12, B60C11/13 take precedence) - B60C 11/0058: {with different cap rubber layers in the axial direction} - B60C 11/1392: {with chamfered block edges} - B60C 1/0016: {Compositions of the tread} - B60C 11/0306: {Patterns comprising block rows or discontinuous ribs} - B60C 11/0332: {by the footprint-ground contacting area of the tyre tread} - B60C 11/12: characterised by the use of narrow slits or incisions, e.g. sipes - B60C 2011/0025: {Modulus or tan delta} - B60C 2011/0348: {Narrow grooves, i.e. having a width of less than 4 mm} - B60C 2011/0358: {Lateral grooves, i.e. having an angle of 45 to 90 degees to the equatorial plane} - B60C 2011/0383: {at the centre of the tread} - B60C: VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES ## Abstract The present invention provides a tire tread having a configuration and material properties that improve wet traction. In particular, the tread has a specified minimum threshold for chamfer density and a maximum level of complex shear modulus for the material that constitutes the tread in order to optimize the road friction coefficient (p) a tire tread experiences during a wet braking event. This results in better wet traction and a shorter stopping distance during the braking event. ## Claims ### Claim 1 A tread for a tire, the tread comprising: one or more repeating pitches, each repeating pitch comprising tread elements, said tread elements being defined by one or more lateral grooves, said tread elements further comprising leading and trailing edges adjacent said lateral grooves and adjacent sipes found within the tread elements; wherein the tread has a weighted average Chamfer Density (CDw) of at least 15%, wherein a chamfer density (CD) for each of the one or more repeating pitches is: CD = TPLCE TPLE , where, for one repeating pitch, TPLCE is total projected length of the chamfered edges of the one repeating pitch, TPLE is the total projected length of the lateral edges of the one repeating pitch, and wherein the tread elements comprise a rubber composition based upon a diene elastomer, a plasticizing system and a cross-linking system, wherein the rubber composition has a shear modulus G* measured at 60° C. of less than 1.0 MPa. ### Claim 2 (depends on 1) The tread of claim 1, wherein the rubber composition also has a glass transition temperature of between −40° C. and −15° C. ### Claim 3 (depends on 1) The tread of claim 1, wherein there are between 2 and 5 different repeating pitches. ### Claim 4 (depends on 3) The tread of claim 3, wherein the individual pitches from each of the repeating pitches alternate in a pattern along the entire tire tread. ### Claim 5 (depends on 1) The tread of claim 1, wherein the chamfered edges are filleted or rounded. ### Claim 6 (depends on 1) The tread of claim 1, wherein the shear modulus G* measured at 60° C. of between 0.5 MPa and 0.9 MPa. ### Claim 7 (depends on 1) The tread of claim 1, wherein CDw is between 80% and 100%. ### Claim 8 (depends on 7) The tread of claim 7, wherein CDw is about 90%. ### Claim 9 (depends on 1) The tread of claim 1, wherein the tread elements are tread blocks. ### Claim 10 (depends on 1) The tread of claim 1, wherein the shear modulus G* is between 0.75 MPa and 0.85 MPa. ### Claim 11 (depends on 1) The tread of claim 1, wherein the diene elastomer is selected from natural rubber, styrene-butadiene rubber, synthetic polyisoprene rubber, polybutadiene rubber and combinations thereof. ### Claim 12 (depends on 1) The tread of claim 1, wherein the plasticizing system comprises plasticizers selected from a plasticizing oil, a plasticizing resin or combinations thereof. ### Claim 13 (depends on 11) The tread of claim 11, wherein the plasticizing resin is a polylimonene resin. ### Claim 14 (depends on 11) The tread of claim 11, wherein the plasticizing oil is selected from a petroleum based oil, a vegetable oil or combinations thereof. ### Claim 15 (depends on 1) The tread of claim 1, further comprising: additional tread elements formed in one or more of the individual pitches, the additional tread blocks comprising a second rubber composition, wherein at least 80 percent of a total contact surface of all the tread elements on the tread are formed from the first rubber composition. ### Claim 16 (depends on 1) The tread of claim 1, wherein the tread elements further comprise a second rubber composition, wherein at least 80 percent of a total contact surface of all the tread elements on the tread are formed from the first rubber composition. ### Claim 17 (depends on 1) The tread of claim 1, wherein the tire is selected from a passenger vehicle tire or a light truck tire. ### Claim 18 A tread for a tire, the tread comprising: one or more repeating pitches, each repeating pitch comprising tread elements, said tread elements being defined by one or more lateral grooves, said tread elements further comprising leading and trailing edges adjacent said lateral grooves and wherein the tread elements have a contact surface adapted for contacting a road and sipes found within the tread elements; wherein the tread has a weighted average Chamfer Density (CDw) of at least 15%, wherein a chamfer density (CD) for each of the one or more repeating pitches is: CD = TPLCE TPLE , where, for one repeating pitch, TPLCE is total projected length of the chamfer edges of the one repeating pitch, TPLE is the total projected length of the lateral edges of the one repeating pitch, and wherein the contact surface of the tread elements comprises a rubber composition based upon a diene elastomer, a plasticizing system and a cross-linking system, wherein the rubber composition has a shear modulus G* measured at 60° C. of less than 1.0 MPa. ### Claim 19 (depends on 18) The tread of claim 18, wherein the contact surface is made entirely of the rubber composition. ### Claim 20 (depends on 18) The tread of claim 18, wherein at least 90 percent of the contact surface is made entirely of the rubber composition.