Simple Questions (?) 2015 Ram 1500 BigHorn Wheels & Tires

[Herb Tarlic]

I'm confused about OEM wheel rim widths, specifically
- are 17s only 7 inches wide?
- are 20s 8, 8.5 or 9 inches wide? (I've seen all 3 on various websites)

So my recently purchased Ram has stock 20s (noname 275/60/20 tires and 20x8(?) wheels)....and I'm considering dropping down to 17" wheels with 285/70/17 ko2s (the load C type for quieter ride with "mild-mannered occasional offroad).

So its unclear to me what wheel width I should have regardless of whether I switch to 17s (17 x 9 min?) or stick with the 20s (20 x 8.5?).

Thanks.

Edited to add: the two sizes are equivalent in total diameter / revs per mile or close enough for me (less than 0.5mph difference at 60mph). I'm also assuming that I can switch back and forth between 17s and 20s without having any concerns about calipers, rotors, other...please tell me if I'm wrong on that point.

 

[DA67Goatman]

Which style wheels do you have currently? Different style factory wheels were different widths. If you downsize wheels, are you going OEM or Aftermarket? Most 285 70 size tires want something between 7.5-9.5" wide

 

[crash68]

Your correct in the thinking you can switch between the 285/70/17 and 275/60/20 and the speedo will read the same. There shouldn't be any clearance issues with a 17" rim as it was a factory available diameter.
All the factory 17" rims are 7" wide

 

[Herb Tarlic]

Your correct in the thinking you can switch between the 285/70/17 and 275/60/20 and the speedo will read the same. There shouldn't be any clearance issues with a 17" rim as it was a factory available diameter.
All the factory 17" rims are 7" wide

Thanks for your reply. I had read where factory 17s were 7" wide, but then for example on tirerack when I look at wheels it describes 17x8.5 as OEM size! Then I see various websites proclaiming that 285/70/17 must have 8 or 9 or 10 inch widths. At which point my head explodes.

 

[Herb Tarlic]

Which style wheels do you have currently? Different style factory wheels were different widths. If you downsize wheels, are you going OEM or Aftermarket? Most 285 70 size tires want something between 7.5-9.5" wide

I have whatever factory wheels came with 20s on 2015 Ram BigHorn...20x8.

I want to go aftermarket wheels and 285/70/17 ko2s...and am confused about what wheel width to order.

 

[crash68]

Thanks for your reply. I had read where factory 17s were 7" wide, but then for example on tirerack when I look at wheels it describes 17x8.5 as OEM size! Then I see various websites proclaiming that 285/70/17 must have 8 or 9 or 10 inch widths. At which point my head explodes.

I just noticed my post should have included that was for the 2015 model year the 17" rims are 7" wide. The Rebel which has 17" X 8" rims was new for 2016, first year for that trim/package option.
There are lots of people that run 285/70/17 on the factory 17"X7" rims without any problems even though the tire manufacturers recommends at least a 7.5"-8" wide rim. It's best to chalk test the tires to set the determine the air pressure to run in them.
If your buying new rims, go with what the tire manufacturer recommends that the rim you want comes in.