FIGURE-8 TIRE ABRASION TESTBy

Troy CottlesOverview

This vehicle test evaluates 5 sets of tires selected from a larger group of 12 tire brands in 185/70R14 size. These 5 tire sets had tread and belt designs that each demonstrated distinct component combinations. The figure-8 test is an on-vehicle test utilizing forces derived from vehicle mass, speed, and turning radius to apply abrasive side forces to the front tires.

Instrumentation Utilized:

•Walking meter•Laser Non-Contacting Thermometer•Digital Camera•Video Camera•4-Way Tire Wrench•Floor JackTest Site and Conditions:

•Huntsville, AL Drag way paved asphalt parking lot. •Date: 4/28/06•Drivers: Heath Dorning and Troy Cottles•Vehicle: 1999 Honda Civic 2Dr.•Tire inflation pressures: 30 PSI front/29 PSI rear•Honda 14”x5.5” rims•Figure-8 dimensions: Each loop ~25’ x ~15’ outer radius with ~30’ transition.•Vehicle ballasts: LF=200#, RF=150#, LR=150#, RR=100#.•Full throttle in 2nd gear.

Test Tire Sets:•Set 1—Cooper Lifeliner SLE•Set 2—Dunlop SP20FE•Set 3—Federal 735•Set 4—Uniroyal Tiger Paw•Set 5—Bridgestone B700AQ

Object of Research

The object of this research is to evaluate tires for abrasion resistance and heat generation when exposed to the figure-8 test protocol.

Experimental Profile

Five tire sets of the same size were evaluated on the same day, on same surface, and using the same test vehicle over a Figure-8 pattern marked by cones. All tires were 185/70R14 size. Tires were available in full vehicle sets, but upon completion of the third round, it was apparent that the rear tires were not experiencing any significant abrasion and the third test set’s rear tires were left on the test vehicle throughout the rest of the evaluations (replacing front tires only) in the interest of time.

At the onset of the test, consideration was given to running the tires to abrasion failure and air-out. For this reason, the first set was run beyond the point of belt end exposure. During testing of the first tire set, a determination was made not to run to failure, in order to protect the test rims and tires. The point of initial belt exposure was noted in each case. As a result, the final appearance of Set 1tire sections does not represent their initial exposure appearance.

1.LF#64, RF#63: Cooper Lifeliner SLE, 185/70R14 88T, plant code: U9 (U.S. for North America), cure code: 4405, 4305.2.LF#74, RF#75: Dunlop SP20Fe, P185/70R14 87S, plant code: M6 (U.S. for North America), cure code: 0505, 0505.3.LF# 77, RF#80: Federal Supersteel 735, 185/70R14 88T, plant code: 2E (China for North America), cure code: 4705, 4705.4.LF#71, RF#72: Uniroyal Tiger Paw, P185/70R14 87S, plant code: K4 (Mexico for North America), cure code: 3305, 3305.5.LF#88, RF#87: Bridgestone B700AQ, 185/70R14 88T, plant code: 2R (Indonesia for Middle East), cure code: 4905, 4905.

Vehicle alignment was checked to be on specification.

Set 1 featured: a tread cap, a tread base, two steel belts, no belt wedges, no nylon cap plies.Set 2 featured: a tread cap, a tread base, two steel belts, 1x2 wires, belt wedges, no nylon cap plies.Set 3 featured: a tread cap, a tread base, two steel belts, no belt wedges, nylon edge bands.Set 4 featured: a tread cap, a tread base, two steel belts, large belt wedges, no nylon cap plies.Set 5 featured: a tread cap, no tread base, two steel belts, belt wedges, nylon cap plies.

Vehicle Figure 8 TestTypes of tread/belt designs to be evaluated

Cooper Lifeliner SLE

Dunlop SP20FE1x2 wire

UniroyalTigerPaw

Federal 735

BridgestoneB700AQ

Set 1 featured: a tread cap, a tread base, two steel belts, no belt wedges, no nylon cap plies.Set 2 featured: a tread cap, a tread base, two steel belts, 1x2 wires, belt wedges, no nylon cap

plies.Set 3 featured: a tread cap, a tread base, two steel belts, no belt wedges, nylon edge bands.Set 4 featured: a tread cap, a tread base, two steel belts, large belt wedges, no nylon cap plies.Set 5 featured: a tread cap, no tread base, two steel belts, belt wedges, nylon cap plies.

Test Results

Results: Max Heat Build Up Avg. Set Heat Build Up Laps to Belt Exposure

Set 1 (Cooper) 245 degrees F 204 degrees F 90

Set 2 (Dunlop) 256 degrees F 217 degrees F 90

Set 3 (Federal) 239 degrees F 215 degrees F 180

Set 4 (Uniroyal) 258 degrees F 205 degrees F 90

Set 5 (B’stone) 265 degrees F 233 degrees F 70 (nylon exposure); 170

(Vehicle Figure-8 Test)

Location Huntsville Dragway

Date: 4-28-06

Set# 1 2 3 4 5

Tire Brand/Type Cooper Lifeliner SLE Dunlop SP20FE Federal 735 Uniroyal Tiger Paw Bridgestone B700AQ

Time 9:30am 10:30am 11:30am 12:30pm 2:00pm 3:00pm

Ambient Temp. 62degrees 71 degrees 83 degrees 84 degrees 83 degrees

Surface Temp. 62 degrees 87 degrees 92 degrees 112 degrees 110 degrees

Weather Conditions clear, sunny

Front Tire Position LF RF LF RF LF RF LF RF LF RF

Front Tire #s #64 #63 #74 #75 #77 #80 #71 #72 #88 #87

Tire Temps: Set 3 Rear Tires Set 3 Rear Tires

T5 130 130 134 186 169 178 114 108 137 131

T10 148 168 193 198 181 192 168 111 198 205

T20 175 183 193 229 207 240 228 200 215 235

T30 190 186 211 221 211 229 243 239 220 237

T40 198 196 217 231 221 210 215 208 225 220

T50 194 207 219 286 207 213 258 243 257 253

T60 222 214 200 217 211 234 215 235 260 235

T70 210 228 231 243 217 237 215 199 254 235

T80 220 229 218 256 235 223 223 225 256 253

T90 * 214 230 220 230 227 219 221 235 265 258

T100 197 233 218 229 254 259

T110 208 232 222 221 250 282

T120 219 226 219 236 242 235

T130 220 246 218 229 236 234

T140 206 219 212 212 224 224

T150 219 232 220 221 241 231

T160 200 221 234 226

T170 221 212 231 226

T180 217 213

T190 205 233

T200 208 213

T210 203 214

*point of belt exposure

Average Tire Temps 198 210 203.6 229.7 211 219.5 210 200 233.2777778 232

Average of LF and RF Averages 204 216.65 215 205.15 232.7222222

Rank Order Of Temp. (Low to High)   Temp Laps Laps to belt exposure

Cooper Lifeliner SLE 1 204 150 90

Uniroyal Tiger Paw 2 205 90 90

Federal 735 3 215 210 180

Dunlop SP20FE 4 217 90 90

Bridgestone B700AQ 5 233 170 170

Rank Order Of Laps to Exposure (High to Low)    

Federal 735 1 

Bridgestone B700AQ 2 

Cooper Lifeliner SLE/Uniroyal Tiger Paw/Dunlop SP20FE 3 

     

Conclusions

1.Recognizing that there are rubber compounding, construction, tread pattern, and profile influences involved in how a particular tire manages side forces, efforts were made to isolate as many additional variables as

possible by completing the testing within the same day, using the same OE rims, inflating to the same inflation pressure, marking the same course, and testing on the same vehicle and under the same vehicle loads.

2.There was only a 26 degree range of max heat build-up among the 5 sets of tires, and a 29 degree range for the average of the front tires of each set.

3.Sets 1, 2, and 4 had no nylon cap plies. These sets all began exposing steel belts in the tread shoulder area at 90 laps.

4.Set 3 featured nylon edge bands. This tire exposed steel belts in the tread shoulder area at 180 laps.

5.Set 5 featured a nylon cap ply. This tire exposed nylon at 70 laps, but did not expose steel belts in the tread shoulder area until 170 laps.

6.Rank order for laps to exposure of steel belts was as follows: Federal > Bridgestone > Cooper=Uniroyal=Dunlop.

7.Application of a nylon belt cover appears to improve tread area rigidity and reduce tread shoulder distortion during aggressive maneuvers.

APPENDIX

Exhibit 1-Photos of Figure 8 test tires

Exhibit 2-Video of Figure 8 testing