Cooper Discoverer A/T3 4S size question

Cupton · September 9, 2018

Looking for a little advice on the Cooper Discoverer AT3 4S for my ‘18 All Terrain with 20” wheels. Stock size is 275/55/20 and Cooper has that size in the AT3 4S and it’s an XL load tire. Would there be any advantage to jumping up one size and getting the same tire but in a 275/60/20 size? That size is an SL load.

Wondering if there would be an advantage or disadvantage to the stock size in XL or one size up at SL. Both are P rated tires. Really don’t want to go bigger in the width either so I’m going to stay with 275. My truck is bone stock so no lift or level.

Thoughts?

TXGREEK · September 9, 2018

Looking for a little advice on the Cooper Discoverer AT3 4S for my ‘18 All Terrain with 20” wheels. Stock size is 275/55/20 and Cooper has that size in the AT3 4S and it’s an XL load tire. Would there be any advantage to jumping up one size and getting the same tire but in a 275/60/20 size? That size is an SL load.

Wondering if there would be an advantage or disadvantage to the stock size in XL or one size up at SL. Both are P rated tires. Really don’t want to go bigger in the width either so I’m going to stay with 275. My truck is bone stock so no lift or level.

Thoughts?

You’ll be getting a slight taller tire, a small amount of added sidewall girth for rim protection but more weight will definitely consume more mpg’s. I had 275/60/20 on my leveled truck but only to help get rid of the donut wheel look due to leveling. Personally, if not leveling or lifting I’d just get a better tire and stick to same 275/55/20 and avoid larger sizes especially due to their weight and rougher ride.

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TXGREEK · September 9, 2018

If Leveling your truck is on your mind, be prepared, it’ll create a whole bunch of issues for you too. Our upper control arms (UCA’s) are stamped steel now bringing our tires closer in if leveled and keeping same oem wheels, will cause bad rubbing unless you level and get new wheels with different offset.

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Cupton · September 10, 2018

I don't really have any big plans to lift or level so I went ahead and ordered the stock 275/55/r20 Coopers and will get them installed either this afternoon or tomorrow. If in the future I do left/level then I'll look at my tire options then. Thanks all for the advice and input!

Cupton · September 11, 2018

Dumb question and I couldn't find anything using search for my particular question. I was running 35 PSI in my previous Goodyear SRA OEM tires because that's what the door sill plate suggests. Should I still be running 35 PSI with the new coopers even though they are still a passenger rated tire but are XL load, not SL? I know if you go up to a TL size tire from P size you should increase the pressure from what the door sill plate recommends but i stuck to a passenger rated tire. Its the XL vs SL load that has me a little confused.

Any advice? Thank you!

TXGREEK · September 11, 2018

Dumb question and I couldn't find anything using search for my particular question. I was running 35 PSI in my previous Goodyear SRA OEM tires because that's what the door sill plate suggests. Should I still be running 35 PSI with the new coopers even though they are still a passenger rated tire but are XL load, not SL? I know if you go up to a TL size tire from P size you should increase the pressure from what the door sill plate recommends but i stuck to a passenger rated tire. Its the XL vs SL load that has me a little confused.

Any advice? Thank you!

Run the psi as indicated on your door sticker. Just because the tire may be rated higher psi doesn’t mean that’s where you run it at. Higher running psi is for heavy loads and towing. My Nitto Ridge Grapplers are rated at 80 psi, I run them at 35 and love them. If you’re still worried, go online to your tire manufacturer and lookup psi load ratings, from there you’ll see that absolutely no reason to run higher than 35 unless towing or loaded down.

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TXGREEK · September 11, 2018

Here are your tire specs.

https://m.tirerack.com/tires/Spec.jsp?tireMake=Cooper&tireModel=Discoverer+AT3+4S&partnum=76TR0DA4SOWL

44psi is max load psi rated. Easily run them at 35 psi.

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Cupton · September 11, 2018

Great, thanks! They run great at 35 psi, I just wasn’t sure due to the extra weight of the tire compared to the OEM’s if I needed to bump it up a couple psi or not.

TXGREEK · September 11, 2018

Great, thanks! They run great at 35 psi, I just wasn’t sure due to the extra weight of the tire compared to the OEM’s if I needed to bump it up a couple psi or not.

Absolutely, good luck!

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Keith T Jackson · December 5, 2018

On 9/10/2018 at 10:30 AM, Cupton said:

I don't really have any big plans to lift or level so I went ahead and ordered the stock 275/55/r20 Coopers and will get them installed either this afternoon or tomorrow. If in the future I do left/level then I'll look at my tire options then. Thanks all for the advice and input!

I just got a new 2019 GMC Sierra Denali. I really want to change my wheels to 20s and was looking into this tire. You have had it for 3 months. Any thoughts? Are they louder than the factory? Ride better or same? This is going to be a commuter vehicle and not a off road vehicle, I just like the look! Thanks!

Cupton · December 5, 2018

29 minutes ago, Keith T Jackson said:

I just got a new 2019 GMC Sierra Denali. I really want to change my wheels to 20s and was looking into this tire. You have had it for 3 months. Any thoughts? Are they louder than the factory? Ride better or same? This is going to be a commuter vehicle and not a off road vehicle, I just like the look! Thanks!

Awesome so far. Great in rain and the light snow we have had so far in western PA. Road noise is minimal. Seriously, I don’t notice any bit of extra noise compared to the stock tires but my son did just a little which is why I say it’s minimal. Really smooth on the highway too at any speed.