Tires and Wheels

[CaptnJohn]

When ordering a Ford dually the standard tires and wheels are 17" LR E. An option is 20" LR E. Would the option increase the payload? I don't see how as both are LR E but wondering if there is ANY reason to upgrade.....

[A32Deuce]

I think it's just the opposite. Smaller rims have higher load because of more sidewall of tire for load carrying. That's how I understand it reading on the forums.

[moose074]

Assuming the tires are the limiting factor to the payload then possibly yes. The only way to know for sure is to look at payload sticker. Just curious though how big of trl you plan on towing. My 42’ has a pin weight of less than 2700 my Ram dually has payload of almost 5800. I am sure Ford is in the neighborhood

[Jim34RL]

This would depend on the load rating of the tire in the 20" size. Even though they are E rated tires a 20" tire could have a higher load index for that tire.

As an example I am using Nitto Dura Grappler tires on my truck. These are LT285/70R/17 126R load index. The tires are rated for a load of 3,748 LBS at 80PSI instead of the standard 121 load rating 3,197 LBS at 80 PSI which most 17" E tires have.

So, find out the load index for the 20" tire and check out the TIRE Rack Load index chart for LT tires. See attached link:

https://www.tirerack.com/tires/tiret...190531135435:s

[CHICKDOE]

check the rims. when we bought our ram to tow a heavy 5th wheel we were told we had to stay with the standard tires/rims as those rims were steel and could carry the load as opposed to the larger tires/rims which were aluminum and would not carry the load.

we did but i am not totally sure this is correct. and of course there are aftermarket rims.

[NMWildcat]

I can't find any docs right now to support my thoughts, but I've always thought the weight capacities in the door sticker were applicable to the tire/rim size also listed there. So if you have rim/tire size options from the factory, I would think the door sticker would reflect that?
And it goes without saying that if you change tires/rims after market, you need to ensure the load capacities are the same or better.

[SeaDog]

Not sure of the weight difference but I can verify that the 20" tires cost a bunch more when replacing. Other then looks I don't see any reason for the larger tire. My truck came with them.

[ependydad]

Originally Posted by NMWildcat

I can't find any docs right now to support my thoughts, but I've always thought the weight capacities in the door sticker were applicable to the tire/rim size also listed there. So if you have rim/tire size options from the factory, I would think the door sticker would reflect that?

Same, I don't have links/documentation to back it up. But I'm almost positive that you're right. The door placard has to show what it comes from the factory with.

[sunnman]

This doesn’t address load capacity but it addresses affects of changing tire diameter on towing, pro and con. Might help

[upflying]

Originally Posted by A32Deuce

I think it's just the opposite. Smaller rims have higher load because of more sidewall of tire for load carrying. That's how I understand it reading on the forums.

I would also think the 20" wheels will have a rougher ride due to the shorter tire sidewall.
I'd stick with the 17's for a cushier ride.

[frank4711]

Tires have the load they are rated for (C D E ) based on psi .... no change to payload it is what the sticker says on the door .

[moose074]

X2 to NMWildcat and Sea dog, wildcat stated better than I did. When I had my 150 it had 20 inch tires I want better load rating salesman said I could almost buy 18 inch rims and tires for price of 20 inch. The tires were very pricey but stuck with just tires

[frank4711]

When I upgraded to Michelin LT E rated , truck came with 20 inch XL rated, I sold the tires on market place for $600. Good thing new tires were $1100... not bad $500 for best upgrade on my Ram.