Stop using "one-size-fits-all" tire pressures - a science based guide to the right tire pressure

[parb]

I can do all three. Probably tomorrow.

 

[Asnes]

BFG load chart + CAT scale weigh-in is what I use. No guessing required.

 

[globalgregors]

Related to the temp and pressure thing, but something that I ran across last year. Highway driving with 285/70R19s KO3s, a 70-80 degree day, but at 7-10,000 ft altitude, highway driving, probably 75-85mph.. The tires were new and they had been filled to the door plat pressure- 35+ish? I ended up getting pretty high temps, maybe even a high tire temp warning. I'm guessing that the temp would be an issue mainly in highway driving, on hotter days.

What is 'too hot' for a tire like ours? Is there a specific tire inflation target for that? I was loaded, but not over loaded. Two people plus gear.

Yeah, I’ve found the KO3s can accumulate a bit of heat (Atacama Desert, ambient temp mid-30s celsius). Nothing problematic, but noticeably hotter than the KO2s (Simpson/Central Desert, mid-high 40s celsius) for otherwise similar pressure/use on fast gravel with patches of tarmac.

This is the one aspect maybe worth mentioning @parb . Heat accumulation is I gather primarily via side wall flexion when the tyre is subject to dynamic loads, primarily cornering and acceleration/braking however I’ve also noticed it with strong crosswinds. Lower pressures accumulate heat faster (more sidewall movement) and in arid location use this can quickly become a balancing act between optimum pressures for surface conditions versus heat accumulation in the tyre carcass.

On the plus side, the TPMS is a gamechanger in that one has never had a tyre temperature-related failure in a TPMS-equipped vehicle. Have sometimes found it necessary to run higher pressures than one would prefer in the name of keeping temps in check.

Final point worth mentioning maybe is the worst case scenario, which is severly potholed tarmac in high ambient temperatures. Sort of sits outside the highway versus gravel taxonomy. Really difficult to manage pressures and preserve both tyres and rims in this situation, particularly if it persists for 6-700kms and slowing to <40kph or whatever seems unrealistic (perhaps I’m just impatient). Ideas welcome!

 

[TheDocAUS]

Yeah, I’ve found the KO3s can accumulate a bit of heat (Atacama Desert, ambient temp mid-30s celsius). Nothing problematic, but noticeably hotter than the KO2s (Simpson/Central Desert, mid-high 40s celsius) for otherwise similar pressure/use on fast gravel with patches of tarmac.

The Falken Wildpeaks AT4s are definitely running cooler than the KO2s. I just had to put in some more air, the KO2's would quickly go from 35PSI cold to 40PSI. The AT4s only move to around 38PSI after sustained use. Tyre temps are also lower.

My longer review is linked here. My needs are offroad focused, so that influences my review. The second post has just added some observations on highway use.

 

[TCMColorado]

I am running the Mickey Thompson Baja Boss 255/85R17. Love the tire but it heats up substantially when driving at highway speeds, enough to regularly set off the tire temp warning. Increasing pressure does not help reduce the temps.

 

[Tazzieman]

Even though I've lived in a metric country for 55 years, I am partial to PSI ... and pints.
Also I see KO2s are rated for up to 80PSI, so there is some wiggle room for those that chase MPG/Km/L/TikTok hits