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40s On 17s! | Toyo Open Country M/Ts

Posted in How To on November 1, 2012
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The Open Country M/T has more than proven itself in every terrain we know of. Toyo seems to have found the magical median that allows them work well in snow, mud, dirt, rocks, and even sand.

And pavement? Forget about it! They are some of the best mud-terrains we’ve ever rolled down blacktop. For an HD truck guy, this practically bulletproof tire is a great option for traction and for towing ability, and one of the only ones that can be found in a 40-inch radial tire size.

But the 40-inch Toyos could only ever be gotten in a 20- or 22-inch-rim size. And it’s a heavy Load D-range tire with thick sidewalls that don’t allow it to flex as much as it should on lighter vehicles like Jeeps. They are great tires for big trucks that still have to tow like our crew cab Super Duty, but how often do you see a crew cab Super Duty on 40s do some serious wheeling…besides ours?

A picture is worth a thousand words. On the front passenger side of the truck is a 40x15.50R20 Toyo Open County M/T mounted on a 20x10 TrailReady beadlock. On the front driver side is a 40x13.50R17 mounted on a 17x9 Centerline I.C.E. beadlock.

The wheeling world needed a 40 with a smaller wheel diameter and a lighter load rating. New to the market, the load range “C” 40x13.50R17 is just what the off-roader ordered. The carcass is a little lighter, the tread is a little softer, it flexes more easily, and it’s made for a 17-inch wheel. All you need to do now is save up your coins as a high-quality tire still has a high-quality price on it. The good news is that they are about $150 cheaper (each!) than the 40s on 20s.

We put the new Toyos onto our Blazer that had already run the bigger 40x15.50R20 Open Country M/Ts. It came as no surprise that the traction of the 40x13.50R17 was similar to that given by its bigger brother. We did notice that the skinnier tire tended to track a little bit less, both in the dirt and on pavement, and they seemed to grab a bit better on climbs. The load range “C” tire definitely flexed more easily under our 5,000-pound Blazer, but the few-pound-lighter weight difference was negligible. Without question, the 40x13.50R17 was better for our truck (than its bigger brethren) in every way, but we have to admit that we liked the look of the wider 40x15.50R20 tire.

Specs as Tested

Make/Model: Toyo Open Country M/T
Mounted On: Centerline I.C.E. 17x9 wheels, chrome face
Size on Sidewall: 40x13.50R17
Load Range: C
Max Load (Tire): 3,195 pounds
Tire Hardness: 58 on tire durometer at 77.5 degrees F
# Plies in Tread: 3 polyester, 2 steel, 2 nylon
# Plies in Sidewall: 3 polyester
Weight of Tire: 107.5 pounds
Measured Diameter Unloaded: 39.5 inches on 17x9 wheel
Measured Width Unloaded: 13.56 inches on 17x9 wheel
Measured Tread Width: 10.63 inches
Available Sizes: 31 inches to 40 inches tall
Available For: 15-inch all the way up to 22-inch wheels
What We’d Install This Tire On: This is still a heavy tire even though it’s a Load C range tire that flexes decently. It’d be great for a higher horsepower half-ton truck or for a purpose-built off-roader of any kind.

At 12 psi the Toyo Open Country M/T flexed better in rough terrain and had a larger bulge at the contact patch.

We immediately noticed a gummier tread compound (than the Toyo 40 on 20s) when we picked up the tires. With the tread at 77.5 degrees Fahrenheit we tested the 40x13.50R17 Open Country M/Ts to be a 58 on the tire durometer (on the soft side). This is considerably softer than the 40x15.50R20 that measured a 67.

While the softer tire will almost always help with traction, they do succumb to wear a bit more quickly. This is a picture after one good outing. But you must remember that when we go out to test tires, we don’t drive them like they’re gonna be on the truck for 50,000 miles.

Toyo Open Country M/T 40x15.50R20 (left), 40x13.50R17 (center), 37x13.50R17 (right).


Toyo Tires

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