Yokohama ATS tires

[maineSS]

Here's some pics of the 315/75/16 Yokohama ATS tire on the OEM rims compared with the 9x16 Super Swampers that came with my truck. I wanted a tire more suited to pavement so I could use the Swampers offroad before grinding them up. After doing a lot of research, I decided to take Charles' advice on the Yokohamas, but went with a less agressive tread than the MT's. Haven't taken a ride yet, just got them on. I'll have to get a longer stud for the spare tire mount, as the Yoko is too wide to fit!

Pic's #1 and 2 show the width of the Yoko compared to the 9X16- it"s about 2" wider. Technically, it should be on a 7.5- 9" wide rim. Pics #3,4, and 5 show what it looks like in side view compared to the 9X16- it's about 1/2" taller. This is about the biggest tire I'd put on the truck- any larger would tend towards the "Monster Truck" look, where it's more about the tires than the truck.

Unfortunately, Yokohama has ceased production of the MT in 16", so the 16 inch ATS might be next. At some point, someone will hopefully start producing a modern wheel for our bolt pattern in a diameter that will stay popular for awhile.

[maineSS]

Pics 3,4, and 5....

Pic #3 shows the Yoko on the passenger side front, Pic #4 shows the 9x16 Super swamper on the driver side front, and Pic #5 shows the passenger side with the Yoko up front and the Super Swamper on the rear. The most noticeable difference is width.

[maineSS]

wheel/tire weights...

I weighed both wheel/tire assemblies on my bathroom scale, and came up with 108 lbs for the Super Swamper, and 112 lbs for the Yokohama- so they're not that much heavier- except when you're trying to change them!

[Doc Dave]

Good pics,
I know Charles speaks highly of the quality of the Yokohama's. Also they look good mounted up on your truck's wheel.
I am not trying to be negative or start any argument, but was wondering if there is a liability aspect with that size tire on the PW rim. If there was a failure of some kind would a person be liable, as that width is not "Kosher" for the PW wheel?

[maineSS]

Most likely you would be held responsible, since Yokohama certainly would not stand behind mounting their tires on split ring wheels, and Budd is loooong out of business. However, if you go to a custom tubeless wheel- you're still responsible- none of them will accept liability either, that's what "custom" means.

[maineSS]

I took a short road trip today with the Yoko's aired to 38 psi- what a difference compared to the bias-ply Super Swampers! By comparison, riding on bias seems like Cruel and Unusual Punishment! The ATS Yoko's are a D rated tire meant for a max inflation pressure of 50 psi, where they'll support 2950 lbs per tire. I contacted Yokohama for a tire pressure recommendation, so far they're still thinking on it.

Pic #1 shows how the spare mounts from the front, the width sticks out about 2" beyond the running board. Pic #2 shows it from the side. I had to fab a custom stud for the carrier, which I'll show in my next post.

[maineSS]

The original spare tire mount stud is shown in pic #1. It was a homemade affair that engaged with exactly 3 threads when the nut was drawn up as shown in pic #2, which is how I drove around for several years. After I took it off to make a longer replacement, I made a mental note to stop taking things for granted- I can still see the Super Swamper rolling down the road and jumping some import's front bumper to leave knobby imprints across the hood and roof. Pic #3 shows the replacement stud screwed fully into the mount with 10 threads of engagement. I made it long on the theory that it's better to have and not need rather than need and not have extra length. The nut is drawn up where it would be if the spare were mounted with an extra backing plate to align it perpendicular with the running board. If you pull the tire in tight, you'll have about an inch of extra length sticking past the nut.

[maineSS]

I used 2" long 3/4" coarse thread bolt and a 3" long 3/4" fine thread bolt as a starting point (pic #1). I then cut the head off the fine thread bolt and beveled it to 1/2 thickness to allow weld penetration (pic #2). Next, a 12" piece of 2"x 1/8" angle was windowed to allow the two bolts to be centered and clamped during welding (pic #3). The angle should be long enough to allow for holding in a vice without interfering with the clamps. The clamps in the pic are huge, but that was all I could find in the shop during lunch break.

I'm going to shorten the coarse side by at least 5/8"- this will bring the nut flush with the end of the fine end if I add an extra plate to hold the tire straight up & down. Or, I could cut 1" off and pull the tire up tight with the existing mount. Hopefully this will allow me to use the Super Swamper without having to change studs- haven't checked yet. People who want to duplicate this stud can start with either a 1 1/2" long or a 1" long coarse thread bolt depending on their tastes in spare tire mounting.

[W_A_Watson_II]

Very Nice! Don't forget to drill a hole in the outer end to put a cotter key through, that way if the nut lossens it won't come off.

[maineSS]

I may see if a locknut is available in 3/4 x 16- to insure my spare is there if I need it some fine day. Also, the 50 psi rating of the ATS is 3950 lbs- slight error!

Yokohama STILL hasn't come up with an inflation pressure- does anyone know what modern trucks in the 5-6000lb vehicle wt class typically run in 16-16.5" tires?

[W_A_Watson_II]

Yokohama STILL hasn't come up with an inflation pressure- does anyone know what modern trucks in the 5-6000lb vehicle wt class typically run in 16-16.5" tires?

Your best approach is probably the contact patch method. Different people do it differently, but I was first taught to chalk and make a heavy line across the tread and up the side walls a little and drive a short distance. If the line is wore off the tread evenly the tire pressure is good. If the tread line isn't wore to the ends, too much pressure, if the line is wore off the sidewall, too little pressure.

[maineSS]

What I'm wondering about is the shoulder area- where the tire starts angling up to the sidewall. If I were to deflate til that was flat, I think it would definitely be under-inflated. Looking at the tire on pavement reveals full contact until the shoulder area. In the front shot pic comparing the Super Swamper side by side with the Yoko, you'll see that the three center ribs contact, while the outside rib is angling up. I'll post a clearer pic tomorrow.

[maineSS]

I chalked my tires front and rear at 38 psi (pic #1), and went on a brief ride to our local tire store. By the time I got there, they'd worn the chalk as shown in pic #2 (front) and pic #3 (rear). Since the front wheels have positive camber, the outside shoulder will wear more than the inside. The tire guy thought it looked pretty good, so I went on a 54 mile loop, and got 13.5 MPG- best I've ever done, and that included lots of pull-offs to let traffic by, and lots of hills. Road speed was 30-35 MPH- about 2000 rpm on the tach, which is about 3/4 of the governed rpm's. This seems about optimum for fuel economy with the stock 230 in 1949 configuration- it will do better when I'm finally done with it.

[W_A_Watson_II]

Not bad, I'd try 34 psi and see how that looks and rides.

[maineSS]

I may try 36 psi- Yokohama finally recommended 45 psi, but that's for an 8" rim. The 6.5" rim is likely pulling the sidewall in, which may be lifting the outside rib a bit.