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I bought my Tradesman EcoD with 11,500 and it had the P rated stock tires. After towing my trailer a few thousand miles I decided I didn't like the tire squirm I was experiencing and decided to go to E rated Discoverer AT's. I had asked on this forum for advice in advance of the purchase and was told by one poster that I didn't need E rated tires because the P's were more than enough on a half ton truck. I disagree, I have run E's on virtually every truck I have owned and know they are extremely helpful when towing a 6000# travel trailer. The post that caught my eye though was the one telling me I was going to lose mpg with the E's. Much to my surprise I did lose between 2 & 4 mpg when not towing and I was sadly disappointed. My tow mileage however remained almost unchanged. After the last trip with the trailer I left the tires at 65 psi because of laziness, I generally run 45-50 psi unloaded. Much to my surprise my mpg is back up 3 mpg. Seems I need to run them a bit higher to retain my mpg. The only reason I rand 40-50 psi was ride quality. The truck obviously rides a bit stiffer at 65 psi than it does at 50 psi. I can live with that for 3 more mpg. Just thought this was interesting.
Canyon
 

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Interesting finding. I have been pleasantly surprised how well mine tows heavy trailers with the cheapo GY SR-A's at 45 psi. 1 thing that helped me was upgrading rear sway bar to a Helwig. My mechanic suggested those Discoverer AT. btw.
 

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I am back to the stock SRA's after wearing out a set of Falken Wildpeak AT3Ws and a set of Discoverer AT3W
None compare for quietness and fuel economy to the stock SRAs. Traction.....thats another story.
I'm now on my fourth set of tires on the truck. I have a local source for new take off SRAs that are half the price.
 

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I am back to the stock SRA's after wearing out a set of Falken Wildpeak AT3Ws and a set of Discoverer AT3W
None compare for quietness and fuel economy to the stock SRAs. Traction.....thats another story.
I'm now on my fourth set of tires on the truck. I have a local source for new take off SRAs that are half the price.
Hi: Ecosparky... At the moment my Toyo HT tires are flat on one side and my mileage is 4 weeks to a gallon!!!
Dieseldragon North shore of Lake Erie.
 

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2017 1500 Tradesman Ecodiesel 4x4 Quad Cab 3.55 Gears
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I've used the Cooper AT's on my last truck, and I'm on my second set of Cooper HT3 LT 265/70R/17 tires for the Eco. The ride is good, I get a feeling of a firm stance when cornering.

We tow often, half the miles on my Ecodiesel are from towing the RV. Heavy towing use with a lot of crap that adds up in weight puts a strain on the tires, especially the rears. 1 1/2 years ago the DW, dogs and me drove on a x-country ten week 14.5k mile road trip from Alaska to Florida. I bought new Cooper HT3's for the trip replacing the squishy GY's. I only got 28,000 miles when I replaced those Cooper tires with a new set last month. But this extra tire wear isn't Ram exclusive, all my past trucks while towing used up the rubber faster. I really like the firm stance with the Coopers over the OEM GY SRA tires.

I run my Coopers at 65 psi, but in the winter I'll go to 60 psi for the snow and ice. The other part of running street tires on snow and ice is you spin the tires a lot, and that is hard on them. I think I'll pick up set of cheap studded snow tires this year and save the Coopers for summertime.

As for mileage, with the Cooper HT3,s last year running around at my brothers in Washington state for a week, I still got 31 mpg hand calculated with a mix of city, urban and freeway driving. I thought it was pretty friggin good! And like yourself, towing didn't effect range at all from the GY OEM tires at 14.5-15 mpg average, that number never changed. I might of lost 1-2 mpg for unloaded freeway mileage, but I really can't say for sure as we hardly do any unloaded freeway trips at home. All of our freeway miles are usually towing miles.

I won't go back, it's a safety thing along with the convenience of not having flats. I didn't have my Eco for two months when I pick up a small triangle piece of aluminum scrap metal, puncturing the GY OEM tires. Those SRa's are NOT very beefy. While our RV TT is only 21 feet from rear bumper to the ball, and empty of consumables, is about 4500 lbs. A fully loaded up truck and camper has weighed in at 13,200 lbs overall with all the bodies, coolers, spare tires, firewood, etc. I really should get a 2500 with the Cummins as we are on the cusp.

Goodyear SRA P265/70R/17 tires cost about $148 a tire. The Coopers cost me $193 a tire. It's only an extra $45 per tire and a lot of peace of mind.
 

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Actually stock tires show max psi of 44, I believe. The seem to wear evenly at 39-40 psi though.
Another reason to get better rubber, mine at one week had a round 1" rock penetrate the middle of the tread at 32mph on a dirt road. I run Defenders summers at 50 and studded Nokians winters at 45.
The sidewall pressure is 1/2 the bursting pressure, just like bicycle tires.
 

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Discussion Starter #9
Did you try the stock tires at 65lbs? Late edit, I was shown to be wrong in an earlier post. As a side note I usually run P class tires at max inflation.
If I remember correctly, the GY's were maxed at 35psi.
 

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If I remember correctly, the GY's were maxed at 35psi.
Made me look, haha. 44 psi for the SR-A GY tires. My 2005 came with GY HP tires, much worse, hydroplaned at 50% tread. My SRA's are at 8-9/32nds , guess I'm stuck with them for a while.
 

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If I remember correctly, the GY's were maxed at 35psi.
NPRBoy said:
Did you try the stock tires at 65lbs? Late edit, I was shown to be wrong in an earlier post. As a side note I usually run P class tires at max inflation.
If I remember correctly, the GY's were maxed at 35psi.
Wondering if the original tires were run at 65lbs of pressure like the ones giving you the better mileage which are being run at 65lbs of pressure, if you're saying you ran them at 44lbs, then there's no comparison in mpg's between tires run at 65lbs vs tires run at 44lbs, the point being running at a higher pressure gives better mpg, start faster, stop faster and generally are safer.
 

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Stiffer ride, less sidewall flexion, less energy lost both starting and stopping.
Like a bicycle there's a point where road contact is lost with to much pressure, but under a 7,000lb vehicle I wonder what that point would be?
 

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CanyonMan: thanks for the information. The stock goodyears on our truck are about due for replacement at just over 30k miles, wet weather traction is horrible with these tires.
I'd love to put a set of aggressive all terrain tires on it for looks, but can't justify the loss of ride quality and mileage...and the increased road noise.
I am probably going to fork out the coin for the Michelin ATXs as this is the family hauler and rarely gets put into 4x4 mode...it does put is some hauling duty from time to time tho.
 

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I'm in the same boat. Right at 40k and loking at the edges of my tires wondering how long I can put off that purchase. Only putting on 500 miles a month helps make it look like that may be my Christmas present. Not sure how the wet traction is since I don't have to drive in the rain if I don't want to. Also looking at the Michelin since I can pick them up on decent sale at Costco.
 

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I believe i am running the exact same Cooper AT's in E range as the OP. I also noticed the drop in fuel mileage at about 45 psi to keep my ride. I then went to 65 in front and 55 in rear and milleage was almost unchanged from the SRA's but the ride was significantly degraded. I have since dropped to 55 up front and 50 in the rear and milleage seems to be holding well and have gotten a lot of my smooth ride back.
 

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Just got new shoes last week, Discoverer AT3 4S; 275/60r20. No loss in fuel mileage noticed so far. Running at 37 psi as indicated on the door jam sticker.





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