IndexSpeedrating
ZR...Y1upto186mph (300 km/h)
ZR...(..Y)1over186mph (300 km/h)
ZR1over149mph (240 km/h)
RSpecifyingthe speedrating asthe "ZR" indexin tire code4is optionalfor tires upto186mph (300 km/h).
RIfyour tire code4includes "ZR" andthereis no speedrating7,find out whatthe max‐imum speed is fromthe tire manufacturer.
RIf load-bearing index6and speedrating7are in brackets,the maximum speedrating ofyour tire is above186mph (300 km/h).Tofind outthe maximum speed, askthe tiremanufacturer.
All-weather tires and winter tires
IndexSpeedrating
Q M+S2upto100mph (160 km/h)
T M+S2upto118mph (190 km/h)
H M+S2upto130mph (210km/h)
V M+S2upto149mph (240 km/h)
Winter tires bearthe Msnowflake symboland fulfilltherequirements oftheRubber Manu‐facturers Association (RMA) andtheRubberAssociation of Canada (RAC)regardingthe tiretraction on snow.
Load index88:RNo specification given:standard load (SL)tire
R"XL" or "Extra Load":extra load tire orrein‐forced tire
R"Light Load": light load tire
R"C", "D", "E": a loadrangethat depends onthe maximum loadthatthe tire can carryat acertain pressure
Definition oftermsfor tires and loading
Tirestructureandcharacteristics:describesthe number of layersorthe number ofrubber-coated belts inthe tire contact surface andthetirewall. These are made ofsteel,nylon, poly‐ester andother materials.
Bar:metric unitfor tire pressure.14.5038 pounds per square inch (psi) and100 kilopascal (kPa) isthe equivalent of one bar.
DOT (Department ofTransportation):DOT-marked tires fulfilltherequirements oftheUS Department ofTransportation.
Averageweight ofthevehicle occupants:thenumber ofvehicle occupantsfor which thevehi‐cle is designed, multipliedby150 lb (68kg).
1"ZR"stated inthe tire code.2Or "M+S M"for winter tires
Wheels and tires451
these are installed onthevehicle, but does notinclude passengers or luggage.
Maximum tire load:the maximum tire load isthe maximum permissibleweight in kilograms orlbsfor whicha tire is approved.
Maximum permissible tire pressure:maxi‐mum permissible tire pressurefor one tire.
Maximum load on one tire:maximum load onone tire. This is calculatedbydividingthe maxi‐mum axle load of one axlebytwo.
PSI (pounds per square inch):standard unit ofmeasurementfor tire pressure.
Aspectratio:ratio between tire height and tirewidth in percent.
Tirepressure:pressure insidethe tire applyingan outwardforcetoeverysquare inch ofthe tire.The tire pressure is specified in pounds persquare inch (psi), in kilopascals (kPa) or in bar.The tire pressure should only be corrected whenthe tires are cold.
Cold tire pressure:the tires are cold whenthevehicle has been parkedfor at least3 hours
without direct sunlight onthe tires orthevehiclehas been drivenfor lessthan 1 mile (1.6 km).
Tirecontact surface:the part ofthe tirethatcomes into contact with theroad.
Tirebead:the purpose ofthe tire bead istoensurethatthe tire sits securely onthe wheelrim. There are several wire cores inthe tire beadtopreventthe tire fromchanging length onthewheelrim.
Sidewall:the part ofthe tire betweenthe treadandthe tire bead.
Weight of optional equipment:the combinedweight ofthe optional equipmentweighing morethanthereplacedstandard parts and morethan5 lbs (2.3kg).This optional equipment, such ashigh-performance brakes, level control system, aroof luggagerackor high-performance batteries,is not included inthe curbweight andtheweightofthe accessories.
TIN (Tire IdentificationNumber):a uniqueidentification number which can be usedby atire manufacturertoidentify tires,forexample,in a productrecall, andthus identifythe pur‐chasers. The TIN is made up ofthe manufactur‐
er's identity code, tire size, tire type code andthe manufacturing date.
Load-bearing index:the load-bearing index is acodethat containsthe maximum load-bearingcapacity of a tire.
Traction:traction isthe gripresulting from fric‐tion betweenthe tires andtheroad surface.
Wear indicator:narrowbars (treadwear bars)that are distributedoverthe tire contact surface.Ifthe tire tread is level withthe bars,thewearlimit of 1/16in (1.6 mm) has beenreached.
Distribution ofvehicle occupants:distributionofvehicle occupantsover designated seat posi‐tions in avehicle.
Maximum permissible payloadweight:nomi‐nal load and luggage load plus150 lb (68kg)multipliedbythe number of seats inthevehicle.
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