SaniDel

Koz makes a compelling argument for higher tire pressure and for reasons I did not appreciate. Let's see what other GX 460 owners do, but my vote is for what Lexus recommends ... 32 PSI.
Regards,

SaniDel



"My recommendation to increase tire pressure was not based on saving gas. Better gas mileage is just a fringe benefit. I base my recommendation on past experience with previous mid-sized SUVs, trucks and towing thousands of lbs. The best overall ride will be at the highest pressure you can live with, that is near the max rated pressure. 35psi (In a tire rated for 50psi) on a 3 ton vehicle is never going to give the best ride. Only if you like a soft ride and you do a lot of city driving. Increasing the pressure will improve the steering feel (Especially at low speeds) and tighten the handling on the highway. Of course you have to watch how the tires are wearing. I have never had any abnormal wear using 40psi on a truck.

Koz"

Luke27617

iTrader: (2)

I run at 35psi my GX. In my 335i BMW I have ran around 40-42psi if I remember correctly. They have two recommendations based on driving speeds. The faster the speed, the higher PSI.

Craig B

35 PSI in all four tires...

Koz

I disagree with the amount of improved mileage that was posted. I have personally gained 2 mpg on a 4600 lbs vehicle (That gets 17 to 18 mpg) by increasing the pressure to its max recommended pressure. That kind of throws out the .3 % per pound of increase, in my personal experience. I also disagree that running higher pressures will cause abnormal wear on the tires. As long as you do not exceed the max rated pressure there will not be abnormal wear on the inside tread of the tire. Not only does increasing the air pressure increase mileage and improve handling, it will also increase tire life.

You have nothing to lose by increasing the pressure. Try it and see if it is something you can live with. You have to give it a week or so to get used to it. After that you will forget all about it.

Koz

SaniDel

2010 GX 460 Owner's Manual Page 760 Specifications for Tires and Wheels

Koz

Those recommendations are to provide a nice soft ride. The easy way to find the best pressure for your vehicle, driving style and tires is the chalk test. Get the tires up to operating temp and draw a line across the tires. Drive the vehicle the way you will be driving most of time. You may need to do several tests for different driving conditions. Also, you may have different ideal pressures for each tire on the same vehicle. See attached photos.

If you use the chalk method keep increasing pressure until you get the over inflated indications and back down 1psi.

Also those recommendations are based on the OEM tires. Many replacement tires have a higher max rating and need more psi. Depending on the tire rating (Weight carrying) the max psi rating will increase dramatically. You can see 44, 50, 65 and even 80 psi. If you are towing with LT tires (E rated 80psi) you will need to increase pressure significantly and you will need to maintain higher pressure even when not towing. The right tire pressure is something that has to be determined and no one can say one pressure is the right pressure.

First pic - Chalk line across tire
Second - Indicates over inflated
Third - Ideal pressure

Koz

jaleels

"VERY IMPORTANT" My GX came with valve stem covers that said "nitro filled". Does anyone have this also? Many say that nitrogen filled tires have benefits over air filled tires.

SaniDel

Koz is on to something, which was new to me, but it makes sense. Here is an article with more about the chalk line test.

http://www.automedia.com/Optimizing_...cr20010801tp/1


The attached picture shows how the chalk line should wear evenly across the width of the tire. Keep inflating until the chalk line in the center of the tire is more worn, then back off the pressure until it is even.

Makes sense to me, but we won't know what the 'right' pressure is until we try the chalk line test. Time to get out my PSIclops and find some chalk!
Regards,

SaniDel

SaniDel

Am I using the following web site correctly to search for Michelin tires for the GX 460?

http://www.michelinman.com/tire-care...ign=PSNational


Try to find a Michelin tire for the 2010 Lexus GX 460. Here's what I'm seeing:

"PLEASE NOTE We're sorry, our brands do not currently manufacture tires fitting this vehicle's specifications."

However, a search for P265/60R18 finds five Michelin's, including the Latitude® Tour HP, which came on our GX. Once you find that tire you can get the following performance ratings and other information:

http://www.michelinman.com/tire-sele...p/tire-details


The Latitude® Tour HP is best for fuel economy and braking, comfort and wear life are next, but not so good for off road driving. Not surprising as it is described as an All-Season Tire and not as a "mud and snow" tire as the LTX® M/S2.
Regards,

SaniDel

Craig B

It's a lot of hype in my opinion. Regular air is about 80% nitrogen. Mine came with nitrogen at delivery. I installed chrome wheels and Lexus of St. Louis doesn't use nitrogen, so I no longer have nitrogen filled tires...

Koz

If you can get nitrogen for free, get it but it is not worth paying for it. There are advantages to it but again not worth paying for. Tires filled with nitrogen are less affected by temperature (pressure variation) and will maintain pressure longer before needing more. Also there will be less moisture in the tire.

Koz

Craig B

I agree, they want 39.95 to fill 4 tires with nitrogen at a group of local dealers.

SaniDel

I'm convinced ... 35 PSI is a better choice than the 32 PSI recommended by Lexus.

We are starting a three-day road trip on Wednesday, most of it highway driving and on roads we traveled during the summer. The tires were 'upflated' to 35 PSI and our GX tracks straight and smooth, but there is a bit more ride harshness. What we expect is better control and steering at highway speeds, especially on the curvy and hilly Pennsylvania Turnpike.

One of the obvious problems of 32 PSI is avoiding underinflation. Tires change pressure with temperature and lose air over time so it is hard to maintain 32 PSI without avoiding going below 32 PSI. Part of my decision to 'upflate' to 35 PSI was frustration with finding the tire pressure close to 30 PSI on a cool Fall morning. I really don't want to worry about tire pressure as a daily event, much less to check and adjust pressure frequently.
Regards,

SaniDel

Koz

Remember only check and adjust air pressure when tires are cold (not driven on overnight). Also remember you will lose 1 psi per 10 degree temperature change and 1 psi per month.

Koz

JsGX460

I run 35 to 38 depending on how **** I want to be.

In the winter, I'll run 35 to keep a little extra on the ground (at least I have myself convinced).

I'll run 38 in the summer for a little sporter ride with higher mileage.

Can i actually tell a difference, probably not. But I have myself convinced.


I don't know what the TPMS 'zone' is on the GX. probably need to check the manual for that... i can't imagine it'd fire of until over 40psi or under 30?