Which 19.5" tire to choose

2000 F-350 Single Rear wheel has a Rear GAWR of 6,830 lbs. (vs 7,850)

Are you seeking to have a 1,000 lb "safety margin" on the tires, while at the same time overloading your rear axle by 1,000 lbs? Are rear axles immune to failure?

Original LT265/75R16 tire diameter is 31.6" (vs 33" or 34" diameter).

How will the taller tires affect your overloaded truck's grade climbing ability? Will you lose an entire gear at the top end, having to resort to second when you could otherwise be in third, having to resort to first when you could otherwise be in second? If diesel, will the taller tires lug your rpms, which will increase exhaust gas temperatures when climbing? If gas, will the taller tires put you out of peak horsepower range that is generally at higher rpms with gas engines?

What effect will adding 50 to 75 more pounds per tire of unsprung weight have on the longevity of your suspension bushings? How often will you have to change dampeners? How punishing will the ride be?

Is 4,940 + 4,940 = 9,880 lbs of tire capacity needed for a steer axle that is rated at 5,200 lbs? What will that ride be like?

Can you air down steel corded sidewall tires below 80% of their minimum inflation rating (which for the Toyo M608 you are considering is 80 psi) without running the risk of overflexing the steel in the sidewall, which leads to catastrophic zipper failures when reinflated? Is that consistent with increasing your "safety margin"?

You asked for "any information you can share." I strongly suggest reading the "safety" guidelines for 19.5" tires published by the Rubber Manufacturers Association, the Tire Industry Safety Council, and the tire manufacturers themselves, including Toyo, on the risks of running 19.5" tires below the minimum inflation pressures stated on the load inflation table indices.

I've had 19.5" tires on my personal pickup for the last 20 years, btw.

the axel on the SRW is the same as on the DRW you will be fine. I ran the 245/70R19.5s on my 03 F350. Tires I liked the Cooper Roadmaster RM253 in 245/70R19.5s load range G which matched the capacity of the Vision wheels and gave a better ride that the load range H Toyos that I had previously.

I ran Hankook DH01s on my ‘06 F350 SC SRW. I saw some cupping on the front. I ran Vision wheels.

On my F450, it came stock with 19.5s. I started with DH01s, but I switched to Bridgestone M724F tires in front due to cupping in front. Not terminal, but more than I wanted. I like the Bridgestones better although they do cost a bit more. They are recommended for both Steer and Drive. Pretty aggressive, but not quite as aggressive as the DH01s. No cupping with the Bridgestones.

I had the 245/70r19.5 LRH PR16 on my F250 and liked the combination. They were about 33” tall and matched the height of my 275/70r18 tires. Expect these tires to weigh about 125 lbs each when mounted on Vision rims. My brakes handled the extra rotating mass fine with no difference in wear after 30k miles than running my 18”. I added heavier damped shocks to handle the unsprung wheel weight.

Thank you to everyone for the replies and info.

Before this goes any further I need to make a correction to my first post. Heather recommended the 245/70R-19.5” Toyo M608 load range H rated at 4940 lbs. I mistakenly put down 265/R-19.5” when it should have been 245/70R.

Big Toe, to your answer a question no I don’t think my rear axle is immune to failure. But I do think with my current set up the tires are likely the weakest part of the equation. Thank you for bringing up the other points. That is exactly what I was talking about and asking about. I don’t want to create more problems by trying to solve one problem.

Thanks,
swhunter

swhunter wrote:

Heather did recommend the 265/R-19.5” Toyo M608 load range H, 16ply rated at 4940 lbs.

Anyone running 19.5” wheels on a SRW pickup, what tires do you prefer?

Thanks in advance for any information you can share.
swhunter

That is what I bought for my truck: M608Z's in the 265 size. They were a whole whooping $20 (each) more than the 245's but had a very large safety load margin. I run mine at a whole whooping 90PSI in the rear. :)

On my 1997 Ford I recalibrated the speedo for the new tire size but on my 2017 Ford I just live with the 5-6MPH slow freeway reading. I'll use the GPS in my cell phone to know how fast I'm actually going. :)

If I were to do it again I'd go for a less agressive tread. The M608Z's are not quiet.


- Mark0.

I used traction/drive tread on all four corners on my Ford. The open shoulder tread on the front is what caused my tire noise. On my Ram, I have highway/steer up front and traction/drive on the rear. Even though both are 4wd, I find the mixed combination tracts better and is quieter.

So I just went thru this and this is what I ended up with. Vision Rims with Toyo M920 tires (G) rating in 245/70/19.5. I was told they run quieter and smoother than other tires I was considering. I just had these put on a couple days ago so cannot comment other than on smooth road I cannot tell much difference from my Toyo open country tires I was running. These tires will get a 2,000 mile test next week. If I did not need the stability these tires provided, I would have went with method NV HD wheels and Toyo or Nitto Load range F tires or back to the Cooper 295's that have 4080 lbs. rating

Buzzcut1 wrote:
the axel on the SRW is the same as on the DRW you will be fine.

This is often repeated on here but is certainly not true for some trucks and may not be true for any trucks. GM for example uses 1/4" wall tubing for its SRW trucks and 1/2" wall for DRW, even though the center section is the same. Just because an axle uses the same ring and pinion section does not make it the same. Many SRW trucks do have 1/2" wall tubing though, even older ones, so it depends on the truck specifically.

OP: are you sure there are no 18 or 20 inch tires that will support the weight you're carrying? The reason I say this is that conventional light truck tires will have MUCH better traction on soft surfaces, both because they are wider and because they are softer. Truck tires are rated to carry their full weight capacity for the life of the tire, so you do not need a weight cushion. Even though 19.5" tires might have a tread that looks aggressive compared to steer type tires, I think you're going to be surprised at how little traction they offer with the stiff sidewalls and hard rubber compound. 19.5 tires are designed primarily for weight carrying and stability. Vehicles with 19.5" tires are primarily local delivery trucks like you'd see UPS and FedEx use, as well as tow trucks and similar. Outside of the military, medium duty trucks are seldom used off road, and the military uses very aggressive tires compared to what most pickup truck owners would use. If this compromise is necessary for the weight capacity, then obviously don't overload your tires, but you are going to be surprised at the lack of traction compared to light truck tires--that is why no light truck comes with 19.5" wheels and tires.

My 19.5's have not needed more traction, but they do not provide flotation on surface material. They will cut through snow, sand and mud until they hit hard pan or the truck bottoms out. Siping the tread will help if you drive in icy conditions since the rubber is harder than an LT tire. I don't drive in wet clay areas, so I cannot attest to how the tread cleans out or packs up.