Cooper Discoverer A/T3 megathread?

Thanks man. Very helpful. Realistically, the AT3s make way more sense for me based on wet traction. I had a pair of old AT3s before they were split into three types— but they weren’t E rated. Never had E rated tires so the LTs will be a better stepping stone too.

 

Go with the e rated XLT if you can.

 

How do you like that size on your GX? Just a few minutes with a heat gun and got 33x10.5 tires to work on a 460 with no rubbing on 4Runner Pro rims.

 

No argument at all about the ST Maxx being a great off-road tire, but I'll be doing too much Texas highway to get to those dirt places thus I'm biasing my decision to loose a bit of that to pickup elsewhere. I'm running 255/85R16 on the ST Maxx, which is 33" and 58 lbs each. I'll be shedding 8 lbs a tire and moving to 31.5" diameter which should help. We'll see; Cooper has 45 day satisfaction warranty.

 

Needed a big hammer and a grinder for them to fit. Love the way they look and they are not terrible with the power of the v8. Still want to re gear and lock it though.

 

The ST maxx and AT3 have a different carcass. St Maxx is a 3 ply very stiff, strong, and good for low pressure applications. the AT3 is going to be less harsh of a ride because it has a 2 ply carcass but is still very strong. The tread stock of all AT3’s are better for wet traction while the st maxx tread stock is the best over all tires for gravel cut and chip applications. If you are doing mostly highway with some overlanding. I would go with the AT3 any day of the week. They will be quieter more comfortable and plenty capable for your applications.

 

although i agree with your end choice having burned through several sets of both with lots of highway miles, it's still true that the internal carcass is the same on the same size tire. i asked Cooper about this specifically. the internal tread design is different but not the carcass.

also, it couldn't be clearer to me on my fifth set running these that the AT3 LTs are noticeably stiffer than the STMaxx on road. the extra rubber/less void space on the AT3s really eats the tire compliance with E range tires on these light trucks. but the differences i watch for are mainly performance-oriented and most wouldn't really notice so much. big difference to me, though. i like both and wish i could just swap them back and forth.

 

I am sorry that a customer service person from Cooper told you the incorrect information tha really hurts when wrong information is give out to people. I live in Findlay, OH were Coopertires headquarter and R&D facility is located and know for a fact that the carcass are different. They may feel the same in your application but you can also look on the sidewall of the tire and see how many ply's are in each tire. I am very good friends with one of the R&D engineers that designs LT tires and he has confirm this with me in previous conversations.

Ultimately it is up to you on which tire you like the best I am just going by what a person who actualy designs cooper products for the last 30 years has told me.

 

all good, it's not a deal or anything.

 

The ST Maxx has a 4 out of 5 star rating for snow where the AT3 only has a 3 star rating and couldn’t meet the severe winter requirements to get the snow flake rating.

This according to Discount Tires:

"The Discoverer AT3 line is composed of three different versions, the AT3 4S, AT3 LT and AT3 XLT. The only version that carries the three-peak mountain snow flake rating for use in sever winter conditions is the AT3 4S.

With that being said, we do have independent 3rd party testing available for the XLT which includes winter grip. The scale is based from 1 to 5 with 3 being average performance and 5 being the best. The AT3 XLT scores 3 out of 5, so average performance in winter conditions when compared to other LT all-terrain tire models."

So the ST Maxx actually performs better in wet snowy conditions with the exception being the AT3 4S model.

 

The ST Maxx were great in the snow. I’ve ran them through the end of this years Minnesota winter and early spring. It was our “extreme social distancing” through the start of the big mess. I’m kinda glad I now don’t need to make snow performance the top priority.

 

sorry didn’t mean it to come off that way.

 

I would usually trust 3rd party testing when looking at data as well. While the ST Maxx is really good in snow all of the new AT3’s are better with the 4S being the best.

Discount tire tests and rates these tires when they come out so it is very difficult to compare tires that were release 9 years apart since the rating scale has changed in that amount of time.

If you would like to talk more about it just send me a PM

 

New rubber arrived, and they get installed today or tomorrow. I'll post my thoughts on this switch soon.

 

Are you going to run the new 265 75 R16 on stock suspension? Or do you have a lift?

 

I’m running an OME suspension.

 

Got ‘em installed today at Discount Tires in Georgetown; nice shop with good customer service. Visually, it’s going from aggressive 33s to 31s; I was more impressed with the tread than anticipated.

These seem like as solid of an AT as Grabber AT2 or ATx. We took an evening drive north on 35 to Jarrell, TX and drove around there a bit then back home. They ran well on gravel ~50mph and rode really nice on the highway at ~75mph. Shedding 1.5” of diameter and 9lbs from each tire seems to have improved trip mileage ~2.5mph. This feels like where I want this beast performing with the 4.88 gears.

I’ll post another update after we take a longer trek when I have a better feel of mileage and handling.

 

Pictures? And did you change your lift?

Almost went to something smaller when I went from the Kenda’s in a 33x10.5 to the XLTs in a 285 but really didn’t want to mess with the settings of my OME BP51s as I got them dialed in right where I want them and we also do a lot of off roading. But I shed right at 10 pounds a corner and have to say I’m very happy with doing so even though the Coopers aren’t as aggressive and won’t perform quite as well when we hit the trails. Also have 4.88 gears and am much happier with them now. Was kinda wishing I had gone the 5.29 route but now with this setup I’m quite satisfied. Can’t imagine what 4.88 gears would be like with a 31” tire. If I ever decide to change my suspension I might go down to a 32. 33’s are great when off roading but otherwise are really too much tire for these trucks.

 

Here's a pic. They certainly don't have the aggressive looks as the 33" ST Maxx tires did... but appearance is way down on my list of priorities.

I didn't change the lift at all; it's the regular full OME suspension in the front and back.

 

Can you update the forum once you get some good off road miles on where the coopers fall short of the Kendas.