Cooper Discoverer STT Pro, A New Chapter

Cooper Discoverer STT Pro, A New Chapter

Get Toyota Cruisers & Trucks Magazine on the App StoreWith  a  long  successful  history  in  the  mud-terrain  tire  market,  Cooper has  finally  found  an  adequate replacement for their renowned Discoverer STT.  After years of R&D, Cooper released their newest mud-terrain  option,  the  Discoverer  STT  Pro.  Cooper  takes  great  pride  in  the  STT  Pro  and  they  have  every right to.


After putting 40,000 hard miles on our old STT set, we were able to take a first-hand look at the remodel and how it stacks up against the original. 

The STT Pro utilizes Cooper’s patented Armor-Tek3 sidewall construction, which consists of a full 3-ply carcass with the third ply overlaying at an angle to maximize carcass protection off-road.  Cooper uses a chemically infused silica and carbon black tread compound to optimize wet traction both on and off-road.  Their new compound should also help improve stopping distances as well as improving rolling resistance to improve fuel economy.

Cooper  also  redesigned  the  inner  tread  layout  by  using  a  3-2  alternating  pattern  that  provides  several benefits  to  include:  reduced  road  noise,  increased  stability  and  handling,  balanced  wear,  increased  mud and soft terrain traction along with reduced tendency for vehicle drift.  We can say first hand that the tire noise has noticeably been reduced from the original STT design.

Within  the  tread  redesign,  Cooper  has  included  some  exclusive  features  to  add  even  more  performance out of the STT Pro.  Asymmetrical scallops on alternating lugs direct mud into mud scoops which provide improved traction in mud.  You will also notice mud release dimples along the shoulder tread block walls that  create  mini  air  pockets,  which  help  prevent  mud  from  sticking  between  the  tread  blocks  and  aid  in self-cleaning capabilities.  Found between the treads, raised rubber ribs and pads  were placed to provide extra rubber gauge in the widest portions to help resist stone drilling and impact damage.

Found between the shoulder lugs and the side biter cleats, is a small groove that generates a designed flex point  in the tire.  This  capacity  to  flex  provides  a smoother ride by  helping  to  dampen impact on  rough roads and gravel. This also allows for the tire to flex easily when aired down, allowing the side biters to better conform around objects and work together with the main tread patter for optimal traction.

Our 2006 Tacoma  was  used  for our testing and  has  seen  its  fair share  of  variable terrain and  conditions with the STT Pro.  Through the rugged mountains of Colorado to the vast deserts of Utah, our early tests were  filled  with adventure.    The  STT  Pro  is  very  comparable  to  the  original  STT  when  taking  on  the rocky terrain found out west where grip and durability are key components for that terrain.

A common battle with tires with their on and off-road trade-offs is the level of grip versus long-term tire wear.  The STT Pro, similar to the original STT, are not the “grippiest” on the rocks.  They are, however, showing  great long-term  life expectations  as  we approach 10,000  miles  on them.   Having  great off-road performance while maintaining long tread life is where I see the STT Pro really standing out amongst the crowd.

This  past  fall,  we  were  able  to  get  a  taste  of  northeast  wheeling  and  quickly  got  introduced  to  the  STT Pro’s  ability to  handle  mucky trail conditions.  We  were impressed by their ability to really  dig  into the ground  and keep  our  rig  moving  forward.  Aired  down,  the  side  biters  were  able  to  aid  in  traction  very well, both on ground and up against the rut walls. 

A  concern  for  those  who  run  mud-terrain  tires  in  the  northern  and/or  mountain  states,  is  winter performance.  I for one was very eager to see how the new design would do in the winter time given the new tread pattern and additional tread siping.  From what  I’ve  experienced so far during the  easy  going Vermont  winter, is  an  overall  improvement in  winter  road performance.  The current  winter is  not  your typical  northeast  winter,  however,  we  have had  a  handful  of  icy  commutes  to  tackle  and  so  far,  we  are impressed with the new design for winter performance. 

Final thoughts on our initial review of the Cooper Discoverer STT Pro are positive.  If you were a fan of the  original  STT,  don’t  be  too  worried  about  change.   Cooper  has  passed  the  torch  to  a  worthy replacement.


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