Bigger tires? Where do they make a difference

The reason I asked the question in the first place was cause I weight my truck and new trailer yesterday. If I figures right I was over by 30 lbs on the GAWR of the rear axle and 350 lbs on the GVWR .
Ok throw out the wife, one dog, extra water hose, extra sewer hose......might leave me room for an extra beer!!!!!! Hmmmmmmm?

So.....what I am getting from some of the posts is.....my axle is actually rated a lot heavier that the GAWR and my tires dictate what I can carry on my rear axle. I my case the 18 in tires are each rated for 3640, thus I could carry up to 7280 lbs on my rear axle.
Hmmmmmm. If that's right now if I could just get the GVW up on the truck. Lol

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???

Only in your mind... ;)

You will get a nice warm and fuzzy feeling that you know your tires are not the limiting factor if you do decide to go over the sticker ratings on the other components... ;)

That has been and will always be the limiting factor to YOU, the owner and driver of said vehicle.

You could put on some 19.5" G rated tires and claim the same thing..

Up to you in the end.

Good luck!

Mitch

Huntindog wrote:

timmac wrote:

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

I do

That's great! Ihad no idea it would be so easy. Can you print me a new sticker for my truck?:R

This internet stuff just keeps getting better. More things that were previously hard or impossible to get are becoming easy every day.:B

Depending upon the state you live in, they may not recognize the door sticker as being the law per say. Only what you pay in fees to drive down the road. So in a sense, yes it is easy to change out the gvwr of a given rig by paying money to your local licensing agent. I've had 8600 gvwr rigs licensed to 12K, an 18200 licensed at 26K, been pulled over at 27k, no overweight ticket mind you. Just told to up license to 28K with in 10 days. As I was under the road bed design limit. Ie 20K per axel, or 500 lbs per inch width of tire, which ever is less. Also assuming your axel are spread apart enough to "BRIDGE" the load over the road bed enough. Hence "Federal Bridge Laws" from a weigh load issue.
With this in mind.....AN LEO CAN and WILL get you off the road if you have an unsafe rig. For the OP, this will not be enough to worry about.
Taller tires as noted WILL lower you initial take off ability. Going from a 31" diam tire and say 4.10's to a 32" diam tire, will now net you an approx 3.95 axel ratio. Go up 2" you are now a 3.73 effictive ratio.
GCWR is a performance standard, look at the new SAE ratings, it is not a law that you can not go over this ratings. Nor is the gvwr that the manufacture lists a law. I have yet to see this stated in ANY states I have looked up. Including here in Washington state where I am. All that matters is the paid for slip of paper in my truck. If I am over this amount....techniquely I am over weight. Even if at say 8200 lbs on my 2000 C2500 which has a door sticker of 8600 lbs, but over my paid for license of 8000 lbs. Or it can go the other way as noted above re in my dumptruck one day.

marty

If you go over to the Ford forum you'll find you can change the ratings. Rating changes are forum based.

it will change the gear ratio

The 245/75R17 is the stock size tire on the F250 and the 275/70R18 is on the F350. The 18" wheel is optional on the F250, but you will not see the ratings sticker change due to the GVWR limit on F250's Class 2B. The Sterling 10.5" used in the F250 and SRW F350 is rated for 9750 lbs, so suspension and wheels are the limiters to having a higher sticker rating if the class limits are ignored.

Was your F350 one of the ones with a down rated GVWR of 10K lbs? Other than a DRW, I have not seen 17's on a F350.

My 6.0 PSD felt little difference between the 17's and 18's when at 19K lbs GCW when on flats. I did find downshifts were earlier and longer on grades by one gear in the 5R110, but the truck never struggled to keep desired speed even when climbing at elevation.

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

I do

FireGuard wrote:
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.

Not true on a Ford. The F250/SRW350 have the same axle. The Dually has a totally different axle. Higher capacity also. It's not just 2 more tires.