Cooper Discoverer A/T3 megathread?

Tire diameter:
To accurately measure tire diameter it is best to wrap a tape measure around the circumference of the tire at centerline, then divide this result by Pi to get diameter (circumference / 3.14). If you try to measure diameter of a tire while on the truck, the weight of the truck deflects the tire about the inch or so you are missing, and the shoulder diameter of a tire is slightly less than the centerline diameter (diameter is stated at centerline and mounted and inflated).

Also SUV and regular standard load car tires (sometimes called P-Metric) are measured at 26 psi, most Light Truck LRC at 50 psi, and most LRE at 80 psi. A LRC tire at 32 psi will have slightly less diameter than it will at 50 psi...

Tire width:
Stated tire width is measured at the maximum section width, not tread width... This is how a 265/75R16 and a 265/70R16 both have a nominal width of 265 mm... Typically the lower aspect ratio tire will have a wider tread width... In this case the 265/70 tread is a wider than the 265/75 tread width.

Stamped max load of an SUV tire compared to same size light truck (LT) tire:
Passenger and SUV tires use a different load equation than Light Truck (LT type) tires; the Light Truck load equation is more conservative since it assumes carrying a high near max load all of the time (higher duty cycle) and assumes higher un-sprung mass/weight of heavier axle and suspension components that pound the tire over pot holes and such. Also an SUV tire when used on a "1/2 ton truck" or in more of a work truck service its stamped max load is reduced by 10% (calculated by max stamped load divided by 1.1).

LT LRE type tires have stronger belts and ply than their SUV brothers even though the sidewall often reads "2 ply poly, 2 steel, 1 nylon"... the actual strength and often thickness and/or cords per inch are higher for the LT type tire, since LT LRE type tires need that strength for 80 psi service on 1 ton type trucks that are anticipated to always be working, always carrying a heavy load. LT LRC is very often the good mid-point for tire structure flexibility for ride quality and some boosted strength to resist off road bruising and snags and punctures. That being said, LRE tires do work well on lighter Toyota trucks at a more suitable on road on highway 30 to 36 psi or so depending on loading and such (the chalk method is good). Many times the LRC option is not available leaving only the LRE option (many manufactures skip LRD in the small to middle sizes, many only offer a LRD in 305 and wider tires).

SUV type tires tend to be tougher than passenger tires but not quite to the Light Truck level which tends to give the SUV tire a smoother ride, slightly better fuel economy, but can be more susceptible to off road sidewall bruising and such... If lots and lots of off-roading with ruts with tree roots and larger rocks are involved then the Light Truck tire option makes sense. Also Light Truck tires tend to have deeper tread depth than SUV tire so they could wear longer per set of tires.

 

Marc - thanks. That makes sense to me and I knew there had to be a good explanation out there!

 

Thank you for sharing! The new sidewall design/s look awesome!

 

For those with load range C's, what are you running for tire pressure? Any chalk tests?

I've not had time to refine mine yet. Had them inflated to 34psi as that was good for my previous Toyos (also LRC). Ride seems good at that pressure.

 

I believe that’s the old AT3, not the AT3 4S.

 

All of the at3 models are light compared to beefier all terrains

 

I have to disagree my AT3 XLT’s are beefy as shit and heavy as shit

 

Well width is an attribute to weight.

The 32” 255’s I’m putting on 17” wheels are 39lbs. The Falken AT3’s I’m running in 265/75/16 are 51lbs

 

My bad. Excluding XLTs because they are their own beast of a tire. They aren’t even available in most standard sizing. I meant the standard AT3’s

 

Just put on a set of Cooper At3 4s tires in 265/75r16. Look and ride great so far. Taking them off road next weekend. Also got another TRD pro wheel/tire for the spare.

 

That looks great! How much did they charge you for the sensors? I have one that just went out

 

Thanks, yeah I’m definitely happy with them. They charged me $35 each for the sensors, said retail was $60. Since I was already getting tires installed there was no extra labor, not sure what it is if you need to get one swapped out on an existing tire. He did scan all of mine and said two were out and two were at 10% - so if you have one out, the others probably aren’t far behind. Might make sense to have them all done, especially if you can get someone to give you a deal on four. I’d definitely recommend checking out discount tire, was impressed with their service.

 

This will probably be my next tire/size. Any chance you could post additional pictures of your rig with these tires mounted? Thank you.

 

Frustrating, I was all set to pull the trigger on the at3 4s’s over the weekend. They were $133/tire at local DT and $160 at DTD. But I was waiting for my new wheels to come in. Wheels shipped today, so I look at tires again, figure I’ll go ahead and buy. Tires are now $160 at DT and not even available at DTD. Had no idea prices fluctuated like that...

 

See if they’ll price match. Mine did, no questions asked. I found the deal online and submitted it on their website, local Discount Tire store called me the next morning.

 

Here’s my AT3 XLT in 315/70/17 that I installed last weekend.

 

Those XLT are fire!! Just wish they had more sizes available and weren't so heavy (E-Load for all the 17" wheel options).

 

Thats a cool rig Teksou!

Max tire size question....What's the biggest tire I can run on a 13 Quad 4x4 LB without a lift ?

 

Cab size doesn’t matter as it doesn’t change anything to do with tires/wheels. Without more info we have no idea what size tire you can fit. Wheels/offset, lift, cmc, pinch welds best??? Tell us what you have.

 

Ya sorry...forgot to add the word STOCK. So no lift like I said and wheels are 16. I still have the mud guards on, but I can remove those. I think I found my answer though...265/75/16 is that correct? Looking at BFG AT & Cooper Discoverer stt pro
Thanks for the help Erik