NEW Shoes for RUBICAT : 37x13.50R17 Cooper Discoverer STT Pro M/T Tires

wayoflife

Administrator
Staff member
As some of you may know, we bought a set of Cooper Discoverer STT Pro tires for our Jeep Renegade a while back and we've been so impressed with how they perform, we decided that we needed to pick up a set for Rubicat as well. We've been wanting to really put these tires to the test and as much as we love our Renegade, there's only so much we can do with it. And as luck would have it, the largest size Cooper makes this tire in is a big and wide 37x13.50R17 - the exact size we were wanting.

For those of you who aren't aware of it, the Discoverer STT Pro replaced its predecessor which was just called the STT and Cooper claims this is their most advanced and extreme tire to date. In addition to it's new and more original tread design that features an aggressive "3-2 center rib design" and shoulder lugs they call "side-biters", the new STT Pro comes with an all new "silica tread compound" and improved sidewall strength through heir "3-Ply Armor-Tek3. For our purposes, we were just happy to see these tires were available in a Load Range E as we have found them to be much tougher on the rocks. Of course, what we like most about the Coopers STT Pro is that they're about $350 a tire where as a Nitto Trail Grappler is about $400.

Cooper Discoverer STT Pro All-Terrain Radial Tire - 40X13.50R17
Cooper Discoverer STT Pro All-Terrain Radial Tire - 37X13.5R17
Cooper Discoverer STT Pro All-Terrain Radial Tire - 37X12.5R17
Cooper Discoverer STT Pro All-Terrain Radial Tire - LT315/70R17


Nitto Trail Grappler 37x12.50R17
http://www.amazon.com/gp/product/B0...37x12.50x17&qid=1456782952&ref_=sr_1_1&sr=8-1

Over 5 tires, that $250 and almost the cost of another tire.

Anyway, our new tires finally arrived yesterday and here are a few teaser shots of what they look like. :cool:

Look what just arrived.
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The leaning tower of tires.
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Our new Cooper STT Pros all unwrapped and ready to be installed.
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Gonna be a loooooooong day.
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Okay, we finally got the 4 tires that were the right size all installed and here's a shot of us airing them up.
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Here are a couple of shots of all 4 wheels and tires completely assembled and ready to be installed on Rubicat.
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And finally, here are a few shots of what they look like mounted on Rubicat.
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I should note that we were able to take Rubicat out for a quick spin and so far, here are some of our initial thoughts on the Cooper STT Pros.
1. They are a LOT quieter than we were expecting. I think being that our Renegade is a unibody, the sound from the tires translate into the cab a lot louder than a JK which has a body on frame and separated by body mounts that are really isolators. Of course, on our Renegade, we were moving from street tires to mud terrains and on Rubicat, we went from bigass Mud Grapplers to these Coopers.

2. Surprisingly, they are a lot rounder than I was expecting. In fact, I didn't notice any shimmy or roughness until I got to about 75+ MPH and even then, it was very slight. Based on the fact that I couldn't feel anything in the steering wheel, I have to think that the minor balance issue is on a rear tire. I have to say that it's almost not off enough to even bother getting them balanced but, I think we'll do it anyway just because we tend to drive on the 75 MPH range on a regular basis.

3. Right off the bat, we aired these tires up to 30 psi and being that they are Load Range E tires, we can definitely feel it. At least, we can feel every stone and crack in the pavement but, that's nothing new to us. We'll be bringing them back down to about 26 psi and I suspect that will help out.

I will be sure to post up more as I think about it. If any of you have any questions, please let me know. :cool:


UPDATE 03/23/16 - 2,500 Mile Review
For those of you who've been asking about our Cooper STT Pros and how they've been performing, here's an updated review that I can give you. So far, we've racked up over 2,500 miles on them and they seem to be wearing exceptionally well. I should note that even for a load range E tire, they seem to be quite comfortable even when running as much as 30 psi. I should also note that these tires have a very flat footprint even at 30 psi and I believe it's due to the score along the edge of the shoulder. With the weight of the Jeep on the tire, this score helps the tread to sit more squarely on the ground. On the highway, the STT Pros are still proving to be pretty quite for a mud terrain tire and unlike the Nitto Trail Grapplers that we were running before, they have NO radial pull or that I can detect so far.

As far as how the STT Pros do off road, so far Cindy and I have found them to perform exceptionally well especially out in Moab. The all new "silica tread compound" they use really hook up well on the rocks and the new tread pattern really does a great job of grabbing onto anything it can dig into and go. We have also found that the large and aggressive "side-biter" shoulder lugs do an amazing job of providing traction especially when little can be found under the tire. When aired down low enough, they flatten out nicely on certain terrain and by virtue of it, they can increase your footprint by essentially become extensions of the tread. As far as airing down goes, I have to say that unlike our old 37" Toyo's which you'd have to take down to about 8 psi to get them to look and feel aired down, simply dropping the STT Pros to about 15 psi will give them the same look and feel and this in spite of them being load range E. Again, I believe this is due to the score that's designed into the edge of the shoulder. As far as sidewall strength goes, we pushed them hard on Behind the Rocks, Hells Revenge, Gold Bar Rim, Golden Spike, Cliffhanger and Top of the World and drove them around town at about 12 psi for an entire week and never once had a problem.

Without question, it's too soon to say how these tires will do in the long run but so far, I'd have to say that Cindy and I are extremely impressed with our new Cooper STT Pros. Granted, we knew we liked them after buying a set for our Renegade but after testing them out in a place like Moab, we're super glad we got them for Rubicat too. If they ever come out with these tires in a 40" size, we'll be sure to get them for Moby too!

I hope this review helps you out and if you have any questions, please don't hesitate to ask. :cool:
 

wayoflife

Administrator
Staff member
Okay, we finally got our 5th tire installed and mounted on Rubicat yesterday and just as the sun was going down, we decided to drive to the end of the street and test them out on the rocks. Here are a few shots for you to enjoy :cool:

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CJW

New member
While running a load range E tire do you feel you need to run less PSI in them both on and off-road? For flex and/or ride? Curious as to what you end up running them at.
 

Brute

Hooked
There is a nice write-up on these in the April Four Wheeler mag...they seem to be a nice set of treads...
 

JKRicky

Member
Really looking forward to seeing these mounted and hearing your review. I'm definitely diggin the tread pattern on those. I also like they come in a 13.50 [emoji106]🏼
 

wayoflife

Administrator
Staff member
While running a load range E tire do you feel you need to run less PSI in them both on and off-road? For flex and/or ride? Curious as to what you end up running them at.

With the 37x13.50 Toyo MT's we used to run back in the day, we ran them at about 28 psi on pavement and at about 8 psi off road. Don't know if that'll be the same with these tires but, we'll see.
 
Glad to see you checking these out. Especially at that price point. Looking forward to seeing them laced up on Rubicat
 

wayoflife

Administrator
Staff member
Sweet! Thanks for the business. I work for Cooper :) hopefully they meet your expectations

No kidding? That's awesome. We really love the set we have on our Renegade and are looking forward to playing a lot harder with these. :thumb:

Now, if I can only get a replacement 5th tire. Turns out one of them showed up in an 20" wheel size :grayno:
 

CJW

New member
With the 37x13.50 Toyo MT's we used to run back in the day, we ran them at about 28 psi on pavement and at about 8 psi off road. Don't know if that'll be the same with these tires but, we'll see.

Thanks for the follow up [emoji106]. I'm interested to see how these do.
 
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