Cooper Discoverer Rugged Trek

Have these on my Tundra (e rated) for ~10k miles & I am pretty impressed with them.
Excellent wear, great wet traction & surprisingly quiet. They are great off road- clean up quickly & shed gravel well. No issues with balancing/alignment or steering wobble.
Thinking about putting a set on the 4Runner but I’ve heard they are more finicky with aggressive AT tires as far as steering wobble, alignment etc. ? I am not lifted & plan to go with the XL load which are 45 lbs in stock size. Any comments/experience greatly appreciated.

 

We run Cooper Discoverer AT3's, size: LT 275-70-17. No problem with the balance or steering wheel shake, but, I think these tires are "pressure sensitive". We have the 10 ply light truck tire, because we like the added protection against rocks when we go for a off-road ride. There has been recent discussion on the tire pressures for different tires, and perhaps some of the time maybe people try to compensate for a stiffer, non-comfortable ride (if they have 10 plys) by airing down. Once upon a time we got a bit of a unbalance feel to the Coopers when we tried to air down for the highway, now we try to keep a 36-38 PSI in them now (on street) and have not experienced it since. I'm not sure I would call the AT3's aggressive. Road force balancing sometimes cures some of the problems you mention, next, find a 'qualified' person who's not in a big hurry to do the balance! Hope this helps.

 

I have 10 ply MT’s, zero issues. Prior to these I had nitto ridge grapplers in 10 ply which are a pretty aggressive AT, zero issues as well.

 

Those look like nice tires.

I wouldn't be concerned about balance issues. I have LT/C 285/70/17 Toyo AT3's and LT/E 295/70/17 Yokohama Geolander MT's and no wobble with either one. If you get wobble, take it to a better shop for a rebalance.

 

Thanks for the recommendation. The at3 lt in 265/70r17 weighs exactly the same as the rugged trek (45 lbs) & looks quite capable off road where I spend ~25 % of my time.
My biggest considerations with the 4Runner are weight & puncture resistance on gravel/rocks. Most e loads are too heavy to my liking & sl loads vulnerable to punctures. Both of these tires seem a good compromise. What exactly is the difference between a “C” load & “XL” load tire ?

 

I'm a big fan of my cooper discover at3 sl, weigh like 44lbs in 285 70 17.

But most cooper tires are heavy. Next im going with a c rated tire, so I'm looking at goodyear territory mt or toyo at3. Or if I go sl rated again maxxis

Sorry not helping much

 

Xl are constructed very similar to a C load. Most XL have a higher load rating so you could theoretically run a lower psi. I have the p rated at3 on my 4Runner. I’ve ran both the C and E on my Silverado. They’re a very good all around tire.

 

I have the XL Rugged Treks on my 2022. Absolutely love them!

 

Are those rrw rr5v? What size tires?

 

After flirting with the idea of running a 285/70 MT (Yoko G003) I've decided to do the more "sensible" thing for now and run the Rugged Treks in stock size XL load. I'm still planning a 2/1-ish dobinsons lift and think it will look fine with stock size tire - especially as agressive as these look. If I find them inadequate in the future I can swap UCAs and slap on 285 MTs at that point.

 

And as usual I changed my mind again. Got the dobinsons lift installed with new UCAs and I'm running these rugged treks in a 285/70 (P load). Had to do a fender liner mod and some trimming but so far they've been surprisingly quiet. That may change as they wear - time will tell. Only been a couple of days but loving them! Wish they had 3pms like the 265 xl loads (not sure why they don't) but I think they'll be fine for my use.

 

For those of you running rugged treks...

I ended up putting a set of P285/70r17 on when I lifted. Running around 38 PSI warm. Have seen as low as 33 PSI cold.

One thing I've noticed, they seem to be "ballooned" where the center tread is taller than the sides. This is visually from the top, and you would expect the bottom to flatten a bit under the weight of the truck. However, roads were salted a couple of weeks ago and I had a bit of a visual "chalk test" and could see the centers are definitely touching where edges are not (by about 1" each side). I haven't taken out calipers to measure but used a twig to measure and the tread depth on the edges doesn't seem as deep as the center.

Now I'm wondering if:
1. I'm running too high PSI (I wouldn't think 38 is too high)
2. This is how the tire is made and the deeper tread depth is really just a taller tire in the center (this could explain why people say they get louder - maybe as they wear you get full contact patch)

Anyone else noticed this with these tires or have insight? I assume I'm just running too high PSI

 

Sounds like you need to do the chalk test on those tires to get the proper PSI dialed in. That’ll give you a reference point for airing up or down.

 

Yeah, that's what I was thinking. The dirt/salt has been a pretty good chalk test so far and it seems they are overinflated. I guess I was thinking a larger tire would require higher PSI but I ran the dunflops between 33-35 and they were fine for 55k and could have gone longer without abnormal wear issues.

I guess the biggest surprise was checking tread depth and seeing the center blocks are 1/16"-3/32" deeper than the edges on a brand new tire (this was the twig method and my abilty to judge small increments). Almost makes me think it's a design thing. That's why I was asking other tire owners before I air down based on what I've seen

 

38 is appropriate for LT285/70/17's on these trucks. But, P (SL) tires can be run much lower. Maybe try 30-32 cold and see how it looks.

The tire pressure genie says 26 PSI for p rated 285's, but I'd feel weird running that low.

 

It's the opposite. Bigger tire = bigger footprint, so lower pressure to support the weight.

 

Good stuff. I will air them down and see what I see.

I just hate to air them down - I was getting about 14.5 MPG after install after 2 fill ups. That's gone up to about 16.5 avg for the next 2 tanks - I think it was bad gas on the first 2. I knew I'd take an MPG hit (which is why I went P rather than E on this first set of tires - mostly on road).

Hopefully getting full contact patch won't drop it that much more - although new tires may cost more than the MPG expense in the long run

 

I've gotten decent mileage driving around at 25 PSI on backroads and gravel roads. I don't think you'll see a significant loss unless you're actually under-inflated.

And, good thinking about fuel economy VS premature tire replacement.

Maybe try to find a good middle ground ground, at 29or 30.

 

I'll have to try lower PSI. They were set to 38 after balance and install - they are pretty smooth with a little wandering. The wandering could also be from the higher PSI and limited contact patch

 

I have these tires (P-rated) on my '23 OR. Very low noise running them around 39-40 in front and 36-37 in rear. Great traction in wet pavement conditions, but I have not done any real offroading with them yet.

 

What size?

 

265/70/17. I would have gone with 285's, but that would have caused the need for even more trimming for clearance after I installed the 1.25" Spidertrax spacers.

 

So zooming in on the photo of your front tire, I see the same thing I'm talking out with mine that make me think the PSI is too high. See attached where it looks like the edges aren't touching the ground the same way the center tread touches based on dirt.

 

Good observation on the photo! I'll see if I notice anything in real life with the truck sitting on level pavement (although maybe this is an effect that tends to happen at speed, not sure). Also, I noticed more stability in the lanes after installing the Spidertrax, so maybe the wider stance helped.

 

I know you know this, but for the folks that don’t… this is what the chalk test is for. You rub chalk across the tire and drive a straight line and see where the chalk wears off. In the case of this pic, the chalk would remain on the outter edge of the tire like you circled.

whether that’s normal for that tire, I don’t know. There does appear to be quite a bit of crowning across the tread.

 

I run my Kenda Klevers R/T load E @32psi, as it states in the door jam. Chalk test was perfect. It does look like you might be overinflated a bit.

 

I have run these on my taco for about 18 months and 20k miles. I noticed the same thing as @FN2187. Ive had them at 28-30 cold up to 36-38 cold. And havent seen much difference in the “balloon” so to speak. I chalked it up to my truck being pretty light (2wd 4banger), but maybe not? They are a bit louder now, but nothing crazy. Still measuring out at 12/32nds though (16/32nds is new for my xl rated 265/70/17s).

 

Without the spacers, would you have had to trim at all for these? I figure the answer is no, but I'm pretty close to pulling the trigger on a new set of ATs (replacing some highway tires) and I just wanted to make sure there wasn't some strange detail I was missing.

 

Stock size AT (265/70/17) on OEM wheels should not require any trimming from what I understand. It's when you add wheel spacers or go aftermarket wheels that change tire positions that can cause rubbing on stock size tires.

 

Before the spacers, I had no rubbing (I already had Bilstein 5100s in the front set for 1.75" lift when I got the rugged treks). Rubbing only started after the spacers. My rugged Treks are 265/70R17 size...don't recall if I said that part before.