Bigger tires? Where do they make a difference

On a SRW your GAWR is based on tire capacity.
Most 1 ton SRW and DRW use the same axle but the DRW has a much higher GAWR because of 4 tires.
So say your SRW tires are rated at 3200 ea, your GAWR is 6400 lbs on the same axle that may be rated for 9k lbs on a DRW.
If you upgrade your tires to 4K lbs ea, technically your GAWR would be 8k lbs or whatever your axle is rated for.
These numbers come from the truck manufacture but if you want the actual axle rating check the axle manufacture for what they designed it for.
You have already mentioned you can't change what the truck is rated for but that seems to be more of a licensing or manufacturer rating.
On the newer 1 ton SRW you can change to a higher weight rated tire and carry more weight, and probably still remain under GVW.
My 16 SRW has a higher GVW by 500 lbs than my 03 DRW had.

"Due to the bigger tires, does this change any of the weight rating..?"

I've put lot's of mods and upgrades on trucks I've owned over the years to make them better tow and haul vehicles. Most of the time I was happy with the improvements they made. I never saw the door sticker numbers change though, so I'd have to say the answer is no. You're pretty much on your own determining what, if anything, your bigger tires have done for you.

:):)

Tundra2084 wrote:
I have a 2012 Ford F-350. According to the sticker on my frame the tires (LT 245 75 R17E) have certain weight ratings......I have LT 275 70 R18E tires on my truck. Due to the bigger tires, does this change any of the weight rating and if so which ones and by how much?

The taller tire WILL change the tow capacity. Taller tire WILL LOWER it. Taller tires change the rear gearing

Tundra2084 wrote:
I know I can't change the GVWR or GAWR, only in this case Ford can!!!! But does it give me more GVW or GAW???

Bigger tires don't change any of the ratings however they will allow the truck to carry more weight especially on the rear axle as it carries most if not all of the trailers pin weight.
The F350 SRW has the Ford Sterling rear axle with I think around a 9k axle rating so those 18" tires won't come close to maxing out the axle itself.

Moved to Tow Vehicle forum from 5th wheels.

I know I can't change the GVWR or GAWR, only in this case Ford can!!!! But does it give me more GVW or GAW???

You're only as strong as your weakest link. If the tires you have now are stronger than what you previously had, you're still at your GAWR. It they're weaker than what you had, you may be weaker if that's the weakest point.

You don't have the authority to change the GVWR or GAWR.

Maybe to clarify.....do the bigger tires change my GVWR or GAWR and if so by how much

It'll say on the tire. 275/70R18 came stock on my truck and they're rated at 3640 each. I believe 17" tires are generally rated lower but I don't know the number.