Wheels and tires

[Oliver15]

Evening all ,

Just picked up my 2020 2500 Duramax W/T and I’ve gotta get rid of the stock 17’’ wheels . Looking at 18 inch with 285/65-18 . I can’t get a straight answer from anyone if this will cause transmissions or Speedo issues ? Also clearance .

[TrailBoss1]

I think it depends on the outside diameter of the tires. Regardless of wheel size, if the outside tire diameter is the same, no speedometer calibration will be necessary. If different, the speed displayed may not be correct. 

[2020_3500HD]

I have a 3500 SRW with the 275/70r18 tires.  I believe that is the same size if your 2500 had the 18” wheel option too. On my dads 2020 2500 Duramax the dealer was able to re-flash for the change over to the taller diameter 18” tires since he stuck with a size that the truck would have came with stock.  

[2020_3500HD]

Also no clearance issues, but his truck is 4wd

[2020_3500HD]

Did some research if your truck has the factory 245 tires the overall diameter is 31.5”, the 265 tires are 31.6”.  Now the 285/65r18 will be 32.6” and the factory 275/70r18 will be 33.7“.  Below is a picture of my truck with the factory 18” tires with aftermarket wheels

[Oliver15]

4 hours ago, 2020_3500HD said:

I have a 3500 SRW with the 275/70r18 tires.  I believe that is the same size if your 2500 had the 18” wheel option too. On my dads 2020 2500 Duramax the dealer was able to re-flash for the change over to the taller diameter 18” tires since he stuck with a size that the truck would have came with stock.  

Great information. Mine is also 4x4 and I’ll look into the flash .