275/65r20 or 305/55r20

Clayton6499 · October 26, 2017

I'm new to the forum. I've been pouring over quite a few of the level lift threads and I've decided on the rough country 2.5 level lift for my 2014 Gmc Sierra 4x4 crew cab. I traded the factory 18s for a set of stock 20s off the All terrain editions. After reading a bunch, I've come to the conclusion I'm getting either a set of 275/65r20 tires or a set 305/55r20. I've seen a lot of good pics of the 305s bit not a whole ton of pictures of the 275s. I like the fact the 275s seem to fill the wheel wells better since they are taller, but I'm worried they won't look as good since they are a bit thinner tire. Anybody on here ran both sizes or seen both in person or have friends running these setups? It's a big purchase and I don't want to regret it afterwards. Opinions and pictures would be greatly appreciated. Thanks.

SuperSierra · October 26, 2017

Might help you if you are planning to keep stock 20s

The 275 are much less wide might look a little funny from the back.

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Turd Ferguson · October 26, 2017

295/60R20 would only be about 1/2" narrower than the 305s and about the same height as the 275s.

dcarl · October 26, 2017

I'm new to the forum. I've been pouring over quite a few of the level lift threads and I've decided on the rough country 2.5 level lift for my 2014 Gmc Sierra 4x4 crew cab. I traded the factory 18s for a set of stock 20s off the All terrain editions. After reading a bunch, I've come to the conclusion I'm getting either a set of 275/65r20 tires or a set 305/55r20. I've seen a lot of good pics of the 305s bit not a whole ton of pictures of the 275s. I like the fact the 275s seem to fill the wheel wells better since they are taller, but I'm worried they won't look as good since they are a bit thinner tire. Anybody on here ran both sizes or seen both in person or have friends running these setups? It's a big purchase and I don't want to regret it afterwards. Opinions and pictures would be greatly appreciated. Thanks.

Another Tire consideration is 285/60R20. I'm running Cooper Discoverer AT3 and like the the tire although they are a bit heavy...

My Toyo Open Country AT2 started giving traction problems at 50% tread wear.

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dcarl · October 27, 2017

Let me also add that the tire specs you see on the tire manufacture websites are not what you will actually end up with when the tire is mounted on the truck. The Cooper Discoverer AT3 in 285/60R20 is advertised as 33.7 in diameter, but when mounted and on the truck the actual height measured from the ground up is right at 33". This correction also makes the speedometer accurate too.

My Toyo's were 275/60R20 supposed to be 33" in dia, but really measured 32" from the ground up....

I'm not sure about the 305/55R20 measurement from the ground up. Spec says 33.23 Dia, so I suspect it's going to be 32" and some change...

Clayton6499 · November 3, 2017

So I did some more reading and after taking yall's input I went and ordered a set of 285/60r20s. I liked the size but didnt like the tire selection. Looked again and good Ole Nitto just started offering their newer Ridge grapplers in that size which i love those tires. Had a set on my old truck. Will be in on tuesday. Pics to follow after they are mounted

Aaron1085 · November 8, 2017

So I did some more reading and after taking yall's input I went and ordered a set of 285/60r20s. I liked the size but didnt like the tire selection. Looked again and good Ole Nitto just started offering their newer Ridge grapplers in that size which i love those tires. Had a set on my old truck. Will be in on tuesday. Pics to follow after they are mounted

And how were those Nitto RG on your precious truck? I drive mainly highway and around town. I’ve heard that the Nitto Terra Grappler May be a quieter tire as it is less aggressive. In turn, slightly cheaper.

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Clayton6499 · November 8, 2017

2 hours ago, Aaron1085 said:

And how were those Nitto RG on your precious truck? I drive mainly highway and around town. I’ve heard that the Nitto Terra Grappler May be a quieter tire as it is less aggressive. In turn, slightly cheaper.

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I had a set of mud grapplers, 2 sets of terra grapplers, one was the original and one set was the newer G2 series, and a set of ridge grapplers all on the same truck. If all you are doing is highway driving, I think the G2s had the best road manners for sure. The ridge grapplers hum just a little. But they look so good. If you do get off the pavement it isn't even close. The ridge grapplers walk all over the terras. I will say this. I bought another set of ridge grapplers instead of terra grapplers.

Clayton6499 · November 8, 2017

This is after the rough country lift and swapping to the all terrain rims

Clayton6499 · November 8, 2017

This is after the tires. They rub just a hair upon full lock on the sway bar. Not enough to concern me.

Clayton6499 · November 8, 2017

Aaron1085 · November 9, 2017

Lovely Clayton. Sorry, what size again? Stock rims or any spacers?

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Clayton6499 · November 9, 2017

Wheel are stock 20s off a 2014 all terrain edition Sierra with no spacers. Rough country 2.5 inch level lift. And the tires are 285/60r20 nitto ridge grapplers.

Edited November 9, 2017 by Clayton6499

Spurshot · November 9, 2017

What I’ve learned... in no particular order

i drive off road for my hunting. It amounts to less than 1% of the miles I drive.
Adequate clearance is when you can turn the wheel to the stop and hit at least some kind of bump without rubbing hard.
The hybrid AT-mud tires I bought (Cooper STMAXX) are reasonably quiet for about the first 1/4 tread life, then get noisy as a neighbor with a chainsaw on a Saturday morning.
An AT-mud hybrid tire hooks up good in the dirt. Much better than a regular AT.
My Cooper tires with the AT3 carcass common to several of their tire models, has a propensity to go out of round. Mine started at about 1/2 tread life and got worse with more mileage.
My off-road driving is really on dirt roads, most are poorly maintained, but still roads.
Of the 1% of miles driven off-road, i rarely encounter mud, mostly because I don’t hunt birds in the rain.
More agressive tread patterns have a detrimental impact on fuel economy.
Larger diameter tires have a detrimental impact on fuel economy, especially stop n go driving.
wider tires have a detrimental impact on fuel economy

Im going to back off to a less aggressive tread pattern tires on the next set.

Edited November 9, 2017 by Spurshot

Lgetz · November 9, 2017

Good points Spurshot. Concerned about the "Chainsaw" comment as I am running the Toyo Open Country RTs. Same problem with ST MAXX getting louder may eventually affect them. Guess its the price one pays for a rugged looking tire.