New GMC Sierra - Tires

[AlanTDickey]

I’m buying a 2015 GMC Sierra. It comes (unfortunately for my tastes) with 20" X 9" wheels. So, the specs on the stock P275/55R20 GY SR-A tires are that they are 11.2” wide (albeit on 8.5” rims) and a diameter of 31.9”: https://www.goodyear.com/en-US/tires/wrangler-sr-a

 

I was looking at the BFG T/A KO2 275/60R20 tires, which are spec’d at 11” wide (on 8”rims) and with a diameter of 32.9”.

 

So, that’s a 1.0” difference in diameter and thus a mere 0.5” difference in radius (they extend 1/2” more in any direction).

 

Will those 32.9”/11” tires fit without rubbing either (i) stock; or (ii) with a 2”-2-1/2” leveling kit; or (iii) do I need more?

 

I’ve read through many of the posts on here, and I’m still not sure of the answer.

 

Is a 1/2" increase in tire radius a problem without major mods?

 

Many thanks in advance for any advice.

[Chris]

With a level, no. A 2" should be fine. And also pay attention to the tread section width which on a 275 is 10.8" I believe. The width you posted is sidewall width. Section width will give you the look and contact patch. Also the 275/60 is the stock size on Ram 1500's, interesting info albeit a mute point.

[Rawyzf]

275 60 fit with a front end level.

[dcarl]

I have the Toyo Open Country 275/60R20 AT2 with a Zone 2" Level kit on mine and the only time I get a rub is a with a sharp turn and suspension bounce, otherwise no problems.

[AlanTDickey]

Thanks for the replies. I finally bought the truck after dealing with some other events --- a 2015 Sierra 150 SLT CC SB.

 

I am thinking of going with 18”x9” wheels and a Rough Country 2.5” leveling kit.

 

Does anyone know whether 33”; 33.5”; or 34” tires will fit well on that?

 

Many thanks in advance for any info.

 

I was thinking of the 34X12.5R18LT:

http://www.tirerack.com/tires/tires.jsp?tireMake=BFGoodrich&tireModel=All-Terrain+T%2FA+KO2&sidewall=Blackwall&partnum=425R8KO2&tab=Specs

 

[AlanTDickey]

Before and after:

 

 

 

 

[robvas]

I’m buying a 2015 GMC Sierra. It comes (unfortunately for my tastes) with 20" X 9" wheels. So, the specs on the stock P275/55R20 GY SR-A tires are that they are 11.2” wide (albeit on 8.5” rims) and a diameter of 31.9”: https://www.goodyear.com/en-US/tires/wrangler-sr-a

 

I was looking at the BFG T/A KO2 275/60R20 tires, which are spec’d at 11” wide (on 8”rims) and with a diameter of 32.9”.

 

So, that’s a 1.0” difference in diameter and thus a mere 0.5” difference in radius (they extend 1/2” more in any direction).

 

Will those 32.9”/11” tires fit without rubbing either (i) stock; or (ii) with a 2”-2-1/2” leveling kit; or (iii) do I need more?

I have those and they fit without any problems. I even ran them for a few weeks before having the level installed. You'll be fine stock.