Load Index 125 - Load Range F

[markehz]

I’m looking to get a set of 35x12.5r20 to install on stock 20” Sahara wheels.
How rough will the ride become?
I know the rule is to stay in a load range C if possible.
The tires I’m looking at are the Nokian Outpost nAT.

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[LazyJL]

Load range F? It will ride like a dump truck.

 

[rcoe]

20'S are already bad I would think load range F would be awful. Those are a tire meant to go on something heavy carrying heavy loads. I have a set of load range F's on my F350.

 

[Vinman]

Load range F? It will ride like a dump truck.

I doubt it would ride that good

 

[Zandcwhite]

It could ride ok, if you run 15psi on the street. Just slow down for the sharp corners.

 

[ParadigmDawg]

It could ride ok, if you run 15psi on the street. Just slow down for the sharp corners.

And be ready to replace them quickly since they will heat up and become damaged.

Why in the heck would you put "F's" on a Jeep?

 

[Zandcwhite]

And be ready to replace them quickly since they will heat up and become damaged.

Why in the heck would you put "F's" on a Jeep?

Not to derail the thread, but I think heating up and damage is mostly internet lore unless you run single digit pressures on the freeway. I've spent decades jumping on roads and highways between trails in the low to mid teens and never had a problem so I never put a lot of stock in it. Back in 2020 we put brand new Yokohama x-mts in a 37x12.50r17 on our 5300lb built JLUR and drove 1100 miles to Moab. Spent all week at 15 psi. Realized at 1am Sunday packing up to head home that I'd forgot my compressor. 3 service stations later, none had working compressors. Too early in the morning to waste anymore time. 1100 miles home at 85mph. No issues or poor handling. 43k miles later I replaced those tires and they still had some decent tread. So much for that damage the internet told me about. Myth thoroughly busted as far as I'm concerned.

 

[Ratbert]

Why in the heck would you put "F's" on a Jeep?

Good question. And why the hell is BFG releasing the 37" KO3 initially in an F (37x12.50R17/F)? No thanks.

 

[azwjowner]

Not to derail the thread, but I think heating up and damage is mostly internet lore unless you run single digit pressures on the freeway. I've spent decades jumping on roads and highways between trails in the low to mid teens and never had a problem so I never put a lot of stock in it. Back in 2020 we put brand new Yokohama x-mts in a 37x12.50r17 on our 5300lb built JLUR and drove 1100 miles to Moab. Spent all week at 15 psi. Realized at 1am Sunday packing up to head home that I'd forgot my compressor. 3 service stations later, none had working compressors. Too early in the morning to waste anymore time. 1100 miles home at 85mph. No issues or poor handling. 43k miles later I replaced those tires and they still had some decent tread. So much for that damage the internet told me about. Myth thoroughly busted as far as I'm concerned.

PSI is tire volume dependent though. 37s can be run at 22 PSI safely, whereas a 32 might require 32 PSI. So the larger your tires, the more you can get away with lower pressures.

If you had aired down stock size Jeep tires to 15 PSI and drove 85 I'm confident you would have had a problem.

 

[markehz]

And be ready to replace them quickly since they will heat up and become damaged.

Why in the heck would you put "F's" on a Jeep?

on that size, the falken wildpeak atw3, mickey thompson bajas, nittos just to name a few are 125 F

 

[Zandcwhite]

PSI is tire volume dependent though. 37s can be run at 22 PSI safely, whereas a 32 might require 32 PSI. So the larger your tires, the more you can get away with lower pressures.

If you had aired down stock size Jeep tires to 15 PSI and drove 85 I'm confident you would have had a problem.

I've done the same on short stints (1-30 miles) on tires as small as 31s over the last 30 years of wheeling, so no I'm not confident that I'd have a problem at all at 15psi. I've jumped in the highway as low as 10 psi and still roll 70mph. In a car sized/type tire it would probably be an issue. Hell in the mojave I'll bomb around the desert at 12psi at the same speeds for hours and I'm guessing washboards are harder on the sidewalls than pavement?

 

[ParadigmDawg]

on that size, the falken wildpeak atw3, mickey thompson bajas, nittos just to name a few are 125 F

Not my Nittos in 35, 37 and 40s.

 

[Zandcwhite]

Not my Nittos in 35, 37 and 40s.

But nitto can manage to build their tires so they weigh more than a like sized tire in a load F so there's that.

 

[Ratbert]

I've done the same on short stints (1-30 miles) on tires as small as 31s over the last 30 years of wheeling, so no I'm not confident that I'd have a problem at all at 15psi. I've jumped in the highway as low as 10 psi and still roll 70mph. In a car sized/type tire it would probably be an issue. Hell in the mojave I'll bomb around the desert at 12psi at the same speeds for hours and I'm guessing washboards are harder on the sidewalls than pavement?

Those sidewalls are deforming with every rotation. Each iteration results in wear and heat. I know you've done it, but I sure wouldn't want to travel far at speed.

 

[2nd 392]

Good question. And why the hell is BFG releasing the 37" KO3 initially in an F (37x12.50R17/F)? No thanks.

How does tire mfg work, ie, changes required for different wheel size vs load rate ? F’s first for 18” up PU wheels makes sense.

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