Overland Journal – August 01, 2019

OVERLAND JOURNAL FALL 2019

23

FIELD TESTED CHRIS CORDES

I doubtmanyofusstoptoappreciateourtiresona daily

basis,butthere’snothingliketheAustralianOutbacktogive

you some perspective.Out there,hundreds of miles from

nothing,andevenfurtherfromsomething,youbegintocher-

ishthepreciousrubberstandingbetweenyouanda verylong,

miserablewalk.Itwasinthisunforgivingenvironmentthat

theCooperDiscovererSTTProproveditsworthandcon-

vincedmetotesta setuponmyreturntotheStates.

The STT Pro is Cooper’s most advanced mud terrain

todate.Theirengineersspentanenormousamountoftime

honingtheacousticengineering,shape,andbalancetodeliver

theoff-pavementperformanceweexpectfromanM/Tbut

withroadmannerscloser toanA/T.Itutilizesa hybrid of

technology from theirroad-orientedproducts likea silica-

infusedrubbercompound,relativelylowtreadvoidratio,and

an alternating3/2 inner blockpattern toimprovestability

whilereducingnoise.TheSTTProsevenfunnelturbulentair

causedbyrotationthroughspeciallysculptedchannelsthat

alterthetire’sharmonics,resultingin thequietestM/TI have

testedtodate.

Weightwaskeptlowatjust 69 poundsforour315/75/

R16inloadrangeE,whichis lighterthanmanyA/Tsonthe

marketinthesamesize,andmeantthatI onlysawa 1.5-to

2-mpgdrop frommypreviousKO2s.Wet weatherperfor-

mancewasexcellentthankstothesilica-infusedrubber,and

tractionfeltstrongwhilecornering.

Alternatingshoulderlugsonthetopedgeofthetirebite

intotheterrainatdifferentangles,givingtheProplentyof

traction asit rolls downthetrail.Side-bitinglugsimprove

gripontheshoulderandsideofthetire,whilealsoincreasing

resistance to punctures or tears. Not that the STT Pro needs

Cooper’sDiscovererSTT Pro is packed

with new technology,but how does it

affect performance?

The Modern

Mud-terrain Tire

muchmorereinforcement,asit alreadycarriesCooper’sAr-

mor-Tek3technology,whichutilizesa cross-hatchpatternof

internalpliesinsteadofthetraditionalstraight-layeredcon-

struction.Thecompanyclaimsthisincreasesstrengthby 66

percentwhilemakingthetires2.5

times more tear resistant in the

sidewallthanthepreviousgener-

ation.Asanaddedbonus,lateral

stability is also increased, coun-

teractingthenaturaltendency of

M/Tstowander.

Theanti-stoneretentionfea-

ture worked great and cleared

outsmallpebbleseasily,butI wasmoreimpressedbytheef-

fectivenessofthemud-releasedimples,whichkeptthetread

voidsopenandreadytoclawtheirwayforwardthroughany

softsurface.Theoffset3/2treadpatterneliminatedtheside-

slipoftenproducedbytraditionalM/Tswhenoffcamberin

themud,and impresseduswithitsgripon rockobstacles.

Even under theslippery conditions encountered in Colo-

rado’shighmountains,theSTTProshelpedmyExcursion

tackleledgeswheremorenimblevehiclesfellshort.

After 15,000miles, thefactory 21/32 treaddepthhad

beenreducedto16/32,orabout 75 percentofthetire’slife.

Theyshowedminimalsignsofcuppingorfeatheringandno

chipping.ThetiresI testedinAustraliahadseen30,000miles

ofharduse,and whiletheyhad morechips and noise had

increased,theywerestill going strong.

US.COOPERTIRE.COM

The STT Prosevenfunnel

turbulentair causedby

rotationthroughspecially

sculptedchannelsthat

alter the tire’sharmonics,

resultingin the quietest

M/T I have tested to date.