Quote:
Originally Posted by Swipter
A little off topic but I just got installed Toyo AT3 P285 70 17. I wanted the LT but that's another story and I don't off road anyway.
They put 41 pounds air in each tire, with a max of 44. I lowered it to 36 and rides great. Toyo says I should use 26 pounds. To me, that sounds a little light. I haven't chalked.
With all this, is 36 lbs ok and can I run 20 lbs when I go off road since they recommended 26 for every day driving?
Thank you so much
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I cannot believe Toyo is saying 26.
Quote:
Originally Posted by Ripper238
This is all good to hear, though not exactly what the numbers imply. But very logical since the real concern/danger is if there was a failure at speed due to heat build up or instability.
I probably wouldn't run below 20psi off roading since even at 35psi my Duratracs seem compliant/soft.
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There are two reasons why lowering the pressure is an offroad ritual for low range offroading:
1/ comfort in choppy terrain
2/ traction in slippery terrain
In addition, airing down plus AWD or 4H is needed for sand (not desert sand, but dunes, beach).
If the tires are compliant, like P metric tires at 32 psi or said LTC, then what you get by airing down offroad is increased chance of sidewall issues. However, in really challenging terrain for traction, airing down will still be needed especially on an SR5 or Limited that don't have a real locker or very aggressive traction control.
Obviously, exactly how much one needs to air down should be done reflexively not just following someone's rules blindly.
If I feel I need more traction, I would air down my LTE to 20 or P metric to 28. Sand is different, but how much depends on the sand.
However, if I intend to keep good pace/4H then I only air down my LTE to 28. I don't air them down for normal dirt roads but that requires a stiff suspension for a comfier ride (opposite effect to street).
The issues with airing down and then driving at speeds too high for low range offroad are pretty significant:
--tire squishes on a bump, in a ditch and if you hit hard enough you can get a pinch flat or damage the wheel even if on proper suspension that can take the hits
--even if you don't get niceties like that, you are killing the sidewall which impacts how the shocks work (now out of position when you need them the most).
So airing down has its reasons but should be done more reflexively than just following a ritual.
Finally, tires and suspension should be chosen together. A stiffer, offroad suspension or a well-adjustable suspension will work better with LTE tires while a soft suspension will work better with lighter SL tires.
On my Outback, I had KO2s on stock suspension and while it worked well on smooth dirt or when going slow it was utterly pathetic on washboard or just any dirt road at street pressures. That's an exaggerated version of what can be experienced on a 4R but same principle. The reverse way of getting the same effect would be running a stiff suspension with some light weight street tires.
