New Toyo OpenCountry A/T IIs have a semi-heavy weight size

The challenge is finding hub centric wheels to PROPERLY fit these up sized tires.
You can slap on oversized tire on a narrow wheel...but what have you gained?
There is no answer to this as the RMA and TRA only publish load ratings for the recommended tire/wheel combinations.
Putting an upsized tire on the wrong wheel = a guess as to what the resultant load rating is.

Plenty of Folks do it, and maybe it's fine...maybe not...

Bill

For both my 2014 Ram and my 2009 F150 the speedometer was low with the stock tires. With the 2" taller tires I put on to replace them, the speedometer was the same percentage over as it was under with the stock tires. Going from 33.5" tires to 35.5" tires on the Ram put the speedometer over 3mph at 75 mph: hardly enough to even think about.

At any rate, it sounds like a lot of members are comparing upgraded tires to the tires that came on their truck. I'd compare them to the largest tire available on that model year truck from the factory and go from there. For example, the current F250 can be ordered with 34.5" tires stock. It's not reasonable to say that a 35" tire is going to cause issues because you are going up from the 32" tire that came on your base model. It won't. It's a half inch taller than a tire offered from Ford. Will it be a little less peppy? Sure. Will it be within what Ford designed? Pretty much.

The real issue comes from going considerably wider than stock. On my F150 I went from stock 275/55r20 to 275/65r20. You could hardly tell the difference.

On my Ram from 285/65r20 to 295/65r20, likewise. It's when people want to go from a 9.5-10" wide tire to a 12.5-13" wide tire that you get mileage and power problems due to increased wind drag and significantly higher weight.

What's always worked for me is this: stay as close to stock width as possible, go up 10 in aspect ratio, and there is rubbing only in extreme situations and little mileage and power penalty. My last 4 full size trucks worked exactly that way.

Drawbacks to 19.5 is the limited number of places making them and the resulting high prices even for a basic steel rim, and the lack of an all terrain tire, only high mileage highway treads designed for commercial trucks.

With some of the tires mentioned the tire diameter is going to be 10% greater than the stock ones and that is going to impact gearing as well as odometer and speedometer accuracy.

It really depends how heavy people pack and the weight of the TC. It's easy to get to 7k lbs at the rear axle before even hitching up. You then need to research whether your OEM rims will handle more weight with heavier tires or if you need to replace both rims and tires. If it is the latter, going to 19.5's is not such a big difference.

BTW: We are discussing SRW 3500's.

Bedlam wrote:
If it was just TC, I might be fine. I have an additional 7k lbs in tow...

I totally agree. But having people recommend 19.5 wheels and tires for a new 3500 carrying a 9ft camper and occasionally pulling a 2500# boat is ridiculous.

If it was just TC, I might be fine. I have an additional 7k lbs in tow...

Bedlam wrote:
The 275 on a 20" rim is a 34" tire. Ford trucks come with tires as short as 31". Your 295 is a 35" tire on a 20" rim. My 33's do well with a GCW of 19k lbs running 3.73 gears, but I would not want 35's with my stock gearing and current weight unless I was a flatlander.

The 6speed automatics being put into current trucks have really low 1st gears that minimize the need for low rear ends. I'm just seeing a lot of older truck owners giving advice to extremely late model truck owners without understanding that current trucks are simply much more capable in every way than even something from 5 years ago.

Over the last week I drove my truck loaded with the camper and family over more than a couple of Northern New Mexico and Colorado passes over 10,000ft with plenty of power to spare: with 35" tires and a 3.42 rear end. 70mph left me in 6th mostly with occasional drops to 5th gear. Current trucks really are a different animal.

Yes...the variety of tires available now is bewildering. I wish someone would come out with a 265/75/16 with greater than 3415# capacity...that would be kewl...or a 285 tire that would fit 16 x 7" OEM wheels.
It is frustrating to find so many tires available that only fit after market lug centric wheels.

The bling factor clearly is drivig the marketing decisions. Folks like us that need strong tires and wheels to go with them lose out...

Bill

The 275 on a 20" rim is a 34" tire. Ford trucks come with tires as short as 31". Your 295 is a 35" tire on a 20" rim. My 33's do well with a GCW of 19k lbs running 3.73 gears, but I would not want 35's with my stock gearing and current weight unless I was a flatlander.

I fail to see the issue with airing down. A 35" tire on an 18" rim has the same sidewall as a 33" tire on a 16" rim. A 35" tire on a 20" rim has the same sidewall as a 31" tire on a 16" rim. Those smaller sizes air down just fine as do my 35" toyo a/t on my factory Ram 20's. These aren't low profile tires. Far from it. And modern diesel trucks run 35" tall tires without sweating a bit. A Ford Super Duty with 20" wheels comes stock with 35s in a 275/65r20. My 2014 Ram 3500 srw runs like a dragster with 295/65r20 Toyo A/Ts, even with my Lance 855 loaded and it is only available with 3.42 gearing. Oh, and they are rated for 4080# each.

These "rules" may have applied a decade ago when every truck came with 16" wheels and less powerful motors and tires were all rated at 3750# max. Current model trucks are more than capable of running 35" tires stock with power to spare and those 35" tires are more than capable of airing down and carrying serious loads safely. I've done Stoney pass in Colorado (a 5 rated trail) in an F150 with a popup truck camper loaded down with a stock height suspension and 275/65r20s. It was more than capable of that and Engineer as well.