I have a question please on a recently purchased 2011 F150 4x4 Lariat screw 6.2 liter. The payload on the door says 1,704 lbs, but that is with the stock p275/65R18 tires. The dealer had swapped these out for p275/55/R20s Pirelli ATR and the larger wheels. I was wondering if I had deduct some weight from the max payload for this change? Thanks

 

Payload = GVWR - curb weight.
So theoretically yes, but it won't be very much. The only sure way to tell is to take the truck to the scales, you probably added more things.

 

Thanks Flixden, Including the running boards, bed liner, and misc other options, there is probably an additional 200-300lbs. I thought I read somewhere, that the bigger tires had more of an impact, but the calculation you mentioned makes sense. I'm thinking about putting a tonneau cover on and didn't want to limit payload too much. I think it should still be okay.

 

since the tires are unsprung weight, I would imagine that the tire would have no impact at all on door jamb sticker outside of what the tires themselves are rated for.

 

Actually, they do have an inpact. The engine still has to lug them around.

Also, larger diameter tires effectively reduce the rear axle ratio, reducing payload.

 

That would assume engine power is the limiting factor, right?!?
I think that the curb weight is normally subtracted from the GVWR to get the payload, and in that case, the wheels and tires do count. It does make sense, because more than making them move, their weight needs to be stopped as well, and for that, a rotating mass is even worse than something in the bed. The tires have more energy to dissipate.
You can't think of it as a static load carrying structure like a deck where the supports don't count as load. This is moving weight here, energy.

 

The wheels and tires definitely count with payload, along with any added options. Take it to a scale and you will know where you are.

 

I was reading some earlier post regarding larger size tires and reduced payloads, but still can't come to a conclusion on payload reduction. I think the reasoning for a greater reduction in payload for larger tires and rims was due to a drop in the tire load rating, not necessarily the small increase in weight for the heavier set-up. According to the Tire Rack, the p275/55/R20s Pirelli ATR max load is 2,409lbs and the original equipment p275/65R18 tires can be either be 2,365, 2,535, or 2,601lbs. The 2,365lbs is for the BF Goodrich Rugged Trail TA (not sure how often these are used as OE.)

 

This is 100% true. If people still doubt it, there is a section in your owner's manual that goes into detail explaining the capacity of the vehicle that can be referenced. The section is probably labeled Tires, Wheels and Loading.

 

Yes, changing wheel/tire sizes does impact payload rating. See page 4-9 at the link below for the exact changes (for 2011 models):

https://www.fleet.ford.com/truckbbas...d_Workbook.pdf


You will need to compare the existing option weight for the wheel/tire combo you have/had, versus the new wheel tire combo to get the net impact.


Tim

 

Am I the only one who thinks we are splitting hairs?

yeah, i get it .... you should never exceed GVWR,

but do you guys seriously scale every load you haul? lumber, blocks, bricks, bags of cement?

i'm as big of a number nerd as they come, but come on ... you think that the GVWR is EXACTLY 7300lbs (or whatever your truck is) ... or is it a number that has been agreed upon by many factors ....

i dunno ...

everything above is all sage advice ...

but 40 lbs of tire, one way or another, isnt really going to matter much ....

like others have said .... weigh the truck if you are inclined to worry about it, and go from there.

 

I totally agree meborder. I'm thinking the whole GVWR and GCWR numbers were invented by lawyers to limit liability for Ford and other manufacturers in case of a lawsuit. While I understand the engineering behind those numbers, unless you exceed them by a very large margin, I have a hard time imagining that it'll be a problem.

 

I think the thought process on some of the earlier posts I read was that the larger tire option reduced the load factor and you would have to decrease the payload by 200'bs-300lbs, not just for the small increase in tire/rim weight. I could be mistaken, but I think this put some payloads (mostly for 2009-2010 F150's) near or under 1,000lbs, which could be less than a passenger car is some instances. After thinking about it some more, It would seem to me that given that the Pirelli's have a load spec of 2,409lbs per tire or 9,636lbs total, this would easily accomodate the GVWR.

 

Larger diameter wheels themselves often have a lower weight rating than smaller ones; I have no idea if the max wheel weight is stamped on the inside of the rims, but I would bet the 20" wheels are part of the issue here. There is more leverage on the wheel when applying sideways loads to it, and to keep the weight of the wheel down, I'm sure they don't increase the metal thickness to compensate.

Also part of the issue here is moving to a low profile tire, like a 55 series, on a truck. Hit a big chuckhole at max GVW, and you are going to be a LOT more likely to bubble the tire and put dents in the rim, or even bend or break the wheel. If one of your tires gets a little nail in it and goes down 5-10 lbs, you don't have nearly as much safety margin as you do with a smaller diameter wheel and a taller tire and you are going to hear really expensive noises when you go thru that chuckhole. The tire pressure monitor systems are far more useful when you have a smaller safety margin. There is a huge business now in wheel repair for people who destroy wheels in the course of everyday driving because the tires are simply not tall enough to protect the wheel. Yes, on a glassy smooth road we can talk about max tire load, but in the real world (I live in Detroit), there are chuckholes that will eat small cars.

And I will note your truck is 4WD. Seems to me Ford is prudent to go really conservative if they anticipate people will go off road at all with rubber band tires. You are gonna hit rocks and stumps out there... Get your truck up to, say, 40 mph, and drive directly up a 6" curb at full GVW. Tell me how you feel about doing this with 3" of tire sidewall height vs 8" of tire sidewall height. I realize this is an exaggeration, but there is a reason off-roaders use REALLY tall sidewall tires.

Frankly, I think low profile tires are silly in terms of usefulness on a truck. They may look blingy and all, but they are in the "lipstick on a pig" territory in terms of function. I've seen inner city guys driving Hummers with 28" wheels and rubber bands for tires. NOT the ticket for banging off rocks off road.... So they're taking a tough off-road vehicle and destroying the capability, kind of like a construction worker wearing women's platform high heel shoes or something.

If you want to use it as a real truck and load it up or tow often, use a smaller diameter wheel and a taller tire. If you want to "wear" the truck (as many people do), run whatever wheels and tires float your boat.
George

 

If you want to use it as a real truck and load it up or tow often, use a smaller diameter wheel and a taller tire. If you want to "wear" the truck (as many people do), run whatever wheels and tires float your boat.
George[/QUOTE]

If I had to do it over again, I would have chosen function over looks, and certainly have gone with the 18 inch tires. While the 20inch tires were already on the truck, I could have gotten the dealer to swap them out, and in fact, I did mention it to them at the time. It's no excuse, but I didn't know there was any difference in function between the sizes, and the salesman indicated that it was an upgraded option.

That said, whereas the 18 inch tires/rims may have a slightly more comfortable ride, I think there's only a moderate impact to payload. According to the link below from dbossman, the 20inch tire/wheel option reduces payload by only about 100lbs.

https://www.fleet.ford.com/truckbbas...d_Workbook.pdf