2021Chevy Silverado LT will GMC2021 AT4 tires and rims fit

Spuds1701 · December 30, 2021

Dumb question but I have a 2021 Chevy Silverado LT. I have an opportunity to get some 2021 GMC at4 20in tires and rims. I was wondering if anybody's had experience installing these? Do they need any modifications? My current tire size is 255/70r17 and the AT4 are 265/60r20

Transient · January 1, 2022

31s versus 32.5. That's a good question that I don't have the answer to. You could always add the AT4 lift kit to be safe. And, the bigger wheel/tire means you'd need to recalibrate the speedo. Since they're factory size wheels and tires you might be able to get that done at the dealer.

RedLT · January 1, 2022

My 2021 Silverado LT came with 275/60 20. Fitment wise there's no issue. Not lifted.

Edited January 1, 2022 by RedLT

Ricky_Starbucks · January 1, 2022

13 hours ago, Transient said:

31s versus 32.5. That's a good question that I don't have the answer to. You could always add the AT4 lift kit to be safe. And, the bigger wheel/tire means you'd need to recalibrate the speedo. Since they're factory size wheels and tires you might be able to get that done at the dealer.

@Spuds1701, let us know if you have luck with getting a dealer to do the recalibration Transient is talking about. I went to war with my dealership I made the purchase from to no avail. They said that GM wouldn't give them the code since I had a 17" spare...which is also what comes when you get the truck with 20s. (Albeit a different tire size, but they specifically told be because of the 17" spare, not the tire size.). The TSB for the recalibration is PIT3271K.

Im still trying dealerships, I have one that said they can do the recalibration for $80, but I'm trying to find more than one that can tell me yes.

Good luck!

Transient · January 2, 2022

9 hours ago, Ricky_Starbucks said:

@Spuds1701, let us know if you have luck with getting a dealer to do the recalibration Transient is talking about. I went to war with my dealership I made the purchase from to no avail. They said that GM wouldn't give them the code since I had a 17" spare...which is also what comes when you get the truck with 20s. (Albeit a different tire size, but they specifically told be because of the 17" spare, not the tire size.). The TSB for the recalibration is PIT3271K.

Im still trying dealerships, I have one that said they can do the recalibration for $80, but I'm trying to find more than one that can tell me yes.

Good luck!

My Trail Boss LT came with a 17" spare, but 18s are on all 4 corners. Dealers using that as a justification to not do something is just being stupid. What will they say if I want to put 20s out 22s on my truck? "Nope. Won't do it because you have a 17" spare." Tarradiddle defined.

Edited January 2, 2022 by Transient

Gangly · January 3, 2022

They will bolt up just fine. Get your speedometer calibrated if you want to, or don’t.

Ricky_Starbucks · January 27, 2022

I finally just heard back from the dealer on trying to get my speedo recalibrated for AT4 wheels and it was a no go. the AT4 has 275/60/20 whereas the 20" option on the Silverado was 265/60/20 so they were "told by GM" there was "no software" for this combination on my vehicle.

Trying to decide if I want to risk going with a Pulsar or not, though my truck is brand new and I want no Warranty issues if I should need to use Warranty Service.

Edited January 27, 2022 by Ricky_Starbucks

dgstarr63 · January 28, 2022

Just be aware that going from a 17" tire to a 20 or 22 will give you a harsher ride. the shorter the sidewall the harder the ride. I guess that some of you would consider me old fashioned, but I don't understand why anyone would want the 20 or 22 rims. If you live in a cold climate the larger rims could cause issues with using tire chains. Check your owners manual for tire sizes that permit the use of chains. My last two Silverado Z71s came with 18" tires. I find the ride and handling to be fine with them, my wet traction improved after switching to Michelin Defender tires from the factory Goodyear's.

crj19 · January 28, 2022

7 hours ago, Ricky_Starbucks said:

I finally just heard back from the dealer on trying to get my speedo recalibrated for AT4 wheels and it was a no go. the AT4 has 275/60/20 whereas the 20" option on the Silverado was 265/60/20 so they were "told by GM" there was "no software" for this combination on my vehicle.

Trying to decide if I want to risk going with a Pulsar or not, though my truck is brand new and I want no Warranty issues if I should need to use Warranty Service.

Your dealer is incorrect, the stock 20 inch tire size on a Silverado is a 275/60/20 the same as the AT4.

latreille89 · January 28, 2022

Put them on and send it. It’ll fit. Half inch here or there isn’t going to do much. My winters are a 1/2” smaller because I have the factory 20” rims with a 33” tire on my LT and I went with an 18” steelie for winter. Try finding a common 33” winter tire thats reasonably priced and fits a 18” rim. 265/70/18 was the closest that was somewhat common size.

Keep in mind, you go from a road tire to an a/t tire, both the same size in paper, they will probably sit different on the truck. As they wear they’ll change too.

Ricky_Starbucks · January 28, 2022

10 hours ago, crj19 said:

Your dealer is incorrect, the stock 20 inch tire size on a Silverado is a 275/60/20 the same as the AT4.

Perhaps they are going strictly by my Trail Boss LT Trim level? If I go to PIT3271K and follow their instructions, the following screenshot is the build out from Chevy website with the 20" option on a Trail Boss LT showing 265/60/20 and not the 275/60/20. No idea why Trim Level would dictate this, especially since the TB comes with factory lift and would have no issues with larger tires.

I get everyone saying it is OK to throw them on, I was just trying to do my due diligence to have everything done right as if it were with the 20s from the factory.

ThatredneckguyJamie · January 28, 2022

My RST came with 275/60/20's agree that the dealer is 100% wrong.

crj19 · January 28, 2022

2 hours ago, Ricky_Starbucks said:

Perhaps they are going strictly by my Trail Boss LT Trim level? If I go to PIT3271K and follow their instructions, the following screenshot is the build out from Chevy website with the 20" option on a Trail Boss LT showing 265/60/20 and not the 275/60/20. No idea why Trim Level would dictate this, especially since the TB comes with factory lift and would have no issues with larger tires.

I get everyone saying it is OK to throw them on, I was just trying to do my due diligence to have everything done right as if it were with the 20s from the factory.

My 2021 RST Z71 has 275/60/20, from Chevy website.

Ricky_Starbucks · January 28, 2022

11 minutes ago, crj19 said:

My 2021 RST Z71 has 275/60/20, from Chevy website.

I guess it is trim level based then, and even though it is avail on other trims dealer (or GM) is being hard about it. Seems I have wasted enough time trying to do it thru the dealer and will either just install or grab PULSAR LT and go that route.

fastk9dad · January 29, 2022

On 1/27/2022 at 3:13 PM, Ricky_Starbucks said:

Trying to decide if I want to risk going with a Pulsar or not, though my truck is brand new and I want no Warranty issues if I should need to use Warranty Service.

Hypertech also has a module just for speedo recalibration, plug and play as well, if you don't need or want all the features of the Pulsar. I think Rough Country sells a Hypertech rebranded model too.