37" x 12.5" Toyo Open Country R/T Trail tires - hydroplaning?

[Sandman 4x4]

Big wide tires are like a big wide ski.

Underneath a big wide skier.

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[tom.mary.glad]

They're not overinflated. I run 39 psi. Anyone who runs an e rated tire lower than that is actually running them underinflated. My wheels have a maximum pressure of 65 psi, so technically I would have to run above 65 psi for them to be "overinflated". They appear to be wearing evenly, and I have not hydroplaned yet.

When Discout Tires mounted mine they inflated to 45-50 psi. Truck was “skittery” on the highway. My 4x4 shop suggested 30psi and that has been great for me. Only have about 2000 miles on them. Probably too early to tell about wear??

 

[Sandman 4x4]

They're not overinflated. I run 39 psi. Anyone who runs an e rated tire lower than that is actually running them underinflated. My wheels have a maximum pressure of 65 psi, so technically I would have to run above 65 psi for them to be "overinflated". They appear to be wearing evenly, and I have not hydroplaned yet.

Oh they are most definitely over inflated, that cause different driving dynamics that are not at all related to the small advantage of wide tires. On the sidewall is the manufacturer’s weight rating, at full psi, but if your vehicle, like a 4,800 lbs-5,100lbs Gladiator does not “need” that much psi, if all the tires combined are rated for 2-3x that much total weight. Matter of fact the manufacturer has a chart that tells you how low you can go to drive at any speed up to the max, while also not having such a harsh ride and sketchy handling, especially in rain. Not to mention what all that unsprung weight added with wide tall tires, everywhere but rock climbing!

 

[HooliganActual]

When Discout Tires mounted mine they inflated to 45-50 psi. Truck was “skittery” on the highway. My 4x4 shop suggested 30psi and that has been great for me. Only have about 2000 miles on them. Probably too early to tell about wear??

I'd agree with a lot of what the others have said. I've run those same tires on my 2020 JTR since I bought it, the 35" version of those same tires on my 2016 JKR since I bought it and the 33" version of the same tire on my wife's 2018 JKR and I see the same thing.

As others have said, you have a big wide tire and a surface with a very low coefficient of friction so it's going to happen. As @Rahkmalla said, that is what hydroplaning is. It is simply the formation of a fluid film of lower friction that forms between the tire and the road surface. If your wheels spin too fast, they pull the water underneath and the weight of the vehicle can't push the water out from between the tire and the road surface fast enough to prevent the fluid film from forming between the tire and road..

This is literally the same phenomena that allows the rolling elements in a bearing race to move "frictionless" when properly lubricated...they "hydroplane" around the bearing race. Additionally, it is essentially the same phenomena that allows you to NOT sink in the sand dunes: the right wheel speed allows you to "hydroplane" on the surface of the sand but when you slow down, you dig in.

Truly the best thing you can do is just slow down in those conditions.

 

[Splenda]

Oh they are most definitely over inflated, that cause different driving dynamics that are not at all related to the small advantage of wide tires. On the sidewall is the manufacturer’s weight rating, at full psi, but if your vehicle, like a 4,800 lbs-5,100lbs Gladiator does not “need” that much psi, if all the tires combined are rated for 2-3x that much total weight. Matter of fact the manufacturer has a chart that tells you how low you can go to drive at any speed up to the max, while also not having such a harsh ride and sketchy handling, especially in rain. Not to mention what all that unsprung weight added with wide tall tires, everywhere but rock climbing!

Everyone seems to be an expert. I just know that I'm running 39 psi, which is very close to the recommended pressure on my truck, and I don't have any issues. I started out at 30 psi when I installed the 37s, and it felt really "sloshy". If I start having issues, I will make changes accordingly.

 

[HooliganActual]

Everyone seems to be an expert. I just know that I'm running 39 psi, which is very close to the recommended pressure on my truck, and I don't have any issues. I started out at 30 psi when I installed the 37s, and it felt really "sloshy". If I start having issues, I will make changes accordingly.

Take all of this with a grain of salt because tire pressures can be endlessly debated around here. It all really depends on the weight of your vehicle, i.e. what extra stuff are you carrying and what parts have you added versus the stiffness of the ride you want.

I have scaled my Gladiator and I know I am a bit over GVWR. If I run 30# on the asphalt I can feel it wanting to track/wander/"be sloshy". I find that 37# or so is pretty good for my application and how I like them to feel underneath me. That's a lot of what the tire pressure comes down to...how you want it to feel underneath you.

 

[Rahkmalla]

They're not overinflated. I run 39 psi. Anyone who runs an e rated tire lower than that is actually running them underinflated. My wheels have a maximum pressure of 65 psi, so technically I would have to run above 65 psi for them to be "overinflated". They appear to be wearing evenly, and I have not hydroplaned yet.

an e rated tire would require less pressure for the same weight bearing... not more.

And maximum tire pressure (ie: your 65) is the maximum safe allowable pressure before you start risking blowouts and has ZERO to do with proper inflation for the weight the tire is being asked to carry.

If you only consider over-the-maximum-allowable-pressure to be overinflated, than by those peculiar standards you've established, a tire could only be considered underinflated if you're losing your bead.

 

[Splenda]

an e rated tire would require less pressure for the same weight bearing... not more.

And maximum tire pressure (ie: your 65) is the maximum safe allowable pressure before you start risking blowouts and has ZERO to do with proper inflation for the weight the tire is being asked to carry.

If you only consider over-the-maximum-allowable-pressure to be overinflated, than by those peculiar standards you've established, a tire could only be considered underinflated if you're losing your bead.

And since I have beadlock wheels, I doubt I would lose a bead, even at extremely low pressures.

 

[Camaroboi13]

I’m with @Splenda here, I run my RT Trail 37s at 39 psi. Fully warmed up they’re up to 44 psi. I’m over 25k miles in and right around 70% tread remaining. These will easily get to the 55k rated range and when they wear out I’ll be buying them again.
And no, they don’t hydroplane any more than any other tire I’ve ran. Hell, I aim for the puddles, I don’t go around them.

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