Koz

The sensor only triggers for a minimum PSI.

Koz

cannysage

OP, 40+ psi does not give you maximum handling, but quite the opposite. You get better traction and handling at lower PSI. 32 will be for optimum handling. I'd run 35-38 for slightly better gas mileage and so I spend less inflating them.

Koz

I never said 40+psi will give you maximum handling. This is what I said; "The right tire pressure is something that has to be determined and no one can say one pressure is the right pressure." I highly doubt running 32psi (on a 44psi max tire) on a 5300lbs vehicle will provide the best handling considering I could not run 32psi on a 4600lbs vehicle. As soon as I get my GX I will test the OEM tires. I will most likely trade up for a better, longer life tire (probably the LTX MS2). It doesn’t make sense to not get credit on a short life tire that I will only get 2/3 decent years of service.

Koz

cannysage

when the psi is too high, less of the side walls contact the road, resulting in less traction. I personally wouldn't inflate mine above 40 psi in any case. 35-37 is where I'd be at. If I were to go on a twisty road up a mountain, then I'd deflate them to 28-30. for offroading, id go down to 23. If I were to go 140mph, then yeah.. 40psi. weight is less relevant, unless you're towing heavy loads. Heavy cars have harder compound material for the tires. It's usually proportion to the weight.

Koz

I'm a very aggressive driver and if I have less then 38lbs the handling becomes sloppy. This is on a 4600lbs SUV. The GX470 is known for having tire problems due to its weight and the 460 weighs almost 500lbs more. Running low pressure could cause flat spots and vibration.

FYI - There is no special/separate compounds used for heavy vehicles. The tire is what it is. The only difference is if you get a higher weight caring rated tire (like E rated which is usually rated for a 80lbs max pressure). The difference is more in the design and construction. A three ply sidewall will make a difference.

Koz

cannysage

if GX470's got issues with the tires, it's definitely not because of its weight. It's gotta be something else. offroad tires are much harder than, let's say, drag radials for race cars. offroad tires are rated 65+ on a durometer (measuring tire hardness) where as other are lower. 38psi is a reasonable level for the gx. but I think you have a misperception that the car will handle better at that level. Handling will definitely will be better at 32 psi, especially for twisty roads and uneven pavement. I run @ 35-38psi only because I do mostly freeway and city driving. If you drive aggressively, you would actually want to 'lower' the psi.

Koz

Many heavy vehicles have this problem (not just Lexus). Read this:

Koz

The sidewall should NEVER make contact with the road surface. If it does you have a way under-inflated tire and tire damage may accrue.

Koz

Koz

Well after two weeks I've come to the conclusion that 40 psi is the ideal tire pressure. The Michelin's are rated at 51 max psi and at 40 psi the ride is still nice and comfortable yet the handling is more agile. I also feel the OEM Michelin's provide a very nice ride.

Koz

MickeyS

Koz, you live in Jersey, so how often do you check your tire pressure, particularly in the winter? Do you put more air in the winter to compensate for the cold temperatures?

Koz

Yes I live in NJ and check every two weeks. There is no need to compensate for cold temps if you check often. You must check and adjust when the tires are cold (after the vehicle sat over night).

Koz

SaniDel

I can't change my vote, but I can change my mind ... I'm convinced that higher is better!

My wife and I have been gradually raising the tire pressure in our GX and evaluating how we like it. We're at 40 PSI in all tires and we like it ... a lot! We did a round trip on the New Jersey Turnpike over the weekend, including a stint in a blinding thunderstorm and the GX tracked straight and true, but most of all was secure and responsive to steering corrections. The ride is as comfortable as at lower pressure ... even over bumps and potholes.

I would like to thank those who participated in this poll and especially Koz for his cogent arguments for higher tire pressure. Would anyone make the case that increasing the tire pressure to more than 40 PSI is advisable? No, I won't be the first to try that, but the tire sidewall rating is 54 PSI!
Regards,

SaniDel


P.S. The tires are Michelin Latitude Tour HP

akfd

I leave it at around 34psi, and whenever the pressure is not at 34psi the dealer will either inflate/deflate the tires until they're at that "magic number."

SaniDel

Our dealer does the same ... the vehicle comes back from service set at 35 PSI, regardless of what I had in the tires.

There's a good argument to be made for lower tire pressure in the winter for traction in snow, but keep our GX in the garage when it snows. Now that we are likely past the threat of snow we'll leave it at 40 PSI ... until our dealer gets it for the next service.
Regards,

SaniDel

Koz

When I first got my GX I ran the pressure at the OEM recommend pressure and immediately knew 32 psi was way too low. The ride was soft and smooth at low speeds but mushy at any speed. I gradually increased the pressure and it seems 40 psi is the sweet spot, for now. As the temp starts to go up for the summer I will be do some testing with the chalk line. I found that you can draw the line and just drive about 30 feet in a straight line (on dry pavement) to get a pretty accurate idea of how much of the tread is making contact. For now 40 psi is working well!

Koz