ABN Panzer

Sorry if this has been asked... sitting in Afghanistan and my search is limited due to network blocks.

My issue & question.

I'm looking to get new tires when I get home.
I currenlty have 275/55/20 and am looking to go to a 275/60/20.
This really only takes it from a 31.9 to a 33 inch tire.

I'm sure I've heard that increasing tire size will affect tow capability... but at the time I thought it only really mattered on larger changes. Example a 31.9 to 35s etc.

I've got 3.55 gearing on a 2010 FX2, 5.4L with the 9800 GVR package.

Will I see any real significant drop in tow capability with a simple 1 inch increase in tire size?

tomb1269

I know that the 2005 owners manual states to subtract 400 lbs from max tow for 18" rims.

f150skidoo

I'm no expert but when i put on oversize tires i went up 2" in tire size but went from a p rated tire to a LT E rated. So i may of lost 800 pounds towing but i feel that it was a wash because the tire can handle the weight a lot better than the stock truck.

ABN Panzer

Hmmm,

Not looking to change the rim size... just the tire itself and only by 1 inch.
However it still may apply. Wouldnt think it would be that much of a difference for an extra inch of rubber.

tomb1269

The tire specs will determine any change in capacity due to the tires. Ford drops the weight due to the rims size only. I would assume it may have something to do with rim weight and height.

smokeywren

Okay, here's the math.

The percentage change is tire revs/mile will be the same as the percentage change in the effective axle ratio. (Longer legs means less towing power/torque).

BFGoodrich LongTrail tires:
275/55R20 = 652 revs/mile
275/60R20 = 630 revs/mile

652 minus 630 = 22
22 divided by 652 = 3.4%

3.55 axle ratio minus 3.4% = 3.42

So your 3.55 axle will "feel like" a 3.42.

I suspect you wouldn't be able to feel the difference.

Only if you were loaded right up against the GCWR of your pickup, with a trailer that weighs around 9,000 pounds, should it make a feelable difference.

No, you don't have a 9,800 GVWR pkg. The most Ford offered was 8,200 GVWR available only with the the HD payload Pkg and 3.73 axle ratio. You probably meant 9,800 tow rating which your truck has if it has the 145" wheelbase.

IronJoce

I'm running the same size and I tow a 5th wheel... can't really tell the difference.

The only thing, you won't find LT rated tires in that size. I went with P rated but Extra Load version (3000lbs each).

Good luck

ABN Panzer

Yep.. Mistyped - thanks for the catch... as well as for the other information... Very helpful!

Thanks!
My OEM tires are already P rated tires... the new ones (bigger) would be as well but have a heavier load rating.


All thanks for the replies!

RedOne

So, what tires did you get and how do you like them?

IronJoce

Cooper Zeon LTZ

They are quiet, drive well even when truck is loaded and they look very good IMO. I run them at 43-44PSI