AN EVALUATION OF STUDDED TIRE PERFORMANCE

RESULTS ARE REPORTED OF TESTS PERFORMED ON STUDDED SNOW TREAD TIRES WITHOUT STUDS. THE FOLLOWING CONCLUSIONS DRAWN' /1/ NEW STUDDED SNOW TIRES INCREASE THE COEFFICIENT OF FRICTION BETWEEN THE TIRE AND GLARE ICE AT A TEMPERATURE OF 25 F, AS MEASURED BY SKID TRAILERS AT 20 MPH, FROM 43 TO 105 PERCENT, /2/ NEW STUDDED SNOW TIRES, CONTAINING NUMBERS OF STUDS NOW GENERALLY AVAILABLE, MOUNTED ON THE REAR WHEELS OF A PASSENGER CAR, DECREASE THE STOPPING DISTANCE ON GLARE ICE AT 25 F FROM 20 MPH BY 13 TO 28 PERCENT, /3/ NEW STUDDED TIRES SIMILARLY INCREASE THE PULLING TRACTION OF THE VEHICLE ON WHICH THEY ARE MOUNTED, /4/ STUDDED TIRES MAY BE SOMEWHAT MORE EFFECTIVE, IN BOTH REDUCING STOPPING DISTANCE AND INCREASING TRACTION, ON TRUCKS THAN ON PASSENGER CARS, /5/ THE EFFECTIVENESS OF STUDDED TIRES DOES NOT APPEAR TO BE DIRECTLY RELATED TO THE NUMBER OF STUDS IN THE TIRE, /6/ STUDDED SNOW TIRES SEEM TO PERFORM THE SAME ON DRY OR WET PAVEMENTS AS SIMILAR TIRES CONTAINING NO STUDS, AND /7/ REINFORCED TIRE CHAINS, MOUNTED ON CONVENTIONAL HIGHWAY TREAD TIRES, PROVIDE MATERIALLY GREATER TRACTION AND STOPPING ABILITY THAN ANY OTHER DEVICES TESTED TO DATE.