My "Low Tire" light came on yesterday. It was cold for the first time in a while. The temp was in the teens. I filled all the tires. I usually run them at around 32 PSI. The last time I checked them was probably last summer, when the temps were around 80. All 4 on the car and the spare were at the low 20s. It's really a big difference between the warm temps of summer and the colder temps of winter. I experience this every winter, so I'm not surprised but the single digit temp this AM when I did the tire check was less than pleasant. I was reminded of the spare when I tried to reset after just airing up the 4 on the car. Here's your reminder if you live in a colder weather area.

 

I should add this to the above post. There is a big difference between the ride quality at the lower and higher tire PSI. I also noticed the current fuel MPG increased significantly.

 

I have found it very rare for the low tire warning to go off on mt LS430 since it is rotation/speed based. In past with leaky rim that was a problem. On the other hand, no TPMS sensors to replace. Just check occasionally, at least seasonally. But if you've owned the car a while hopefully you are already aware.

 

I assumed that it was TPMS. I guess the 2004 model year was too early for that. I should have checked the owner's manual. It makes sense about no TPMS since they were all well below any threshold for being low at just over 20 psi. One must have been lower or higher enough to trip the difference in rolling circumference.

 

I think I will probably lower the pressures a bit, since it affects the ride quality. I'm willing to give up some MPG for a smoother ride. It's possible that the 34 PSI might make the contact patch a bit narrow, resulting in accelerated wear in the center of the tread. I may do a chalk stripe across the tread to check the wear pattern.

 

If I recall, posted pressure is 33. I would not lower it much. Affects tire life and handling. The ride juwst feels more controlled at 33psi. Yes, you feel it a bit more at 33 vs say 30, but car is very smooth even at 33. On another vehicle, an SUV, I do lower the pressure a bit because the suspension is a bit firm (Lincoln Nautilus). But the LS should really be driven close to 33 psi. Maybe a tad lower.

 

The LS430 TPMS does not measure tyre pressure.
It calculates the rolling radius of the tyre using the ABS sensors and after you Reset it, it "learns" the relative rolling radius of all 4 tyres.
So, if they all deflate at exactly the same rate it will not warn you of low tyre pressure as all 4 are still the same relative to each other.
If one deflates but the others do not, then you get the warning.

It's not the best system but as others have said it avoids the need for expensive new sensors once the batteries die.
They are developing battery-less direct TPMS sensors that measure both pressure and temperature, but I have not heard of any car manufacturers fitting them yet.

 

Thanks for the info. I guess I like this system as opposed to the one on my 07 Tundra which is the TPMS. I have different wheels and tires that are not compatible. I did not pop for the new sensors.

 

I see you are also a MC rider. I have a 2002 Honda Goldwing. I believe it was the first year for fuel injection and aluminum frame. It still weighs about 1/2 with me on it and some stuff in the bags. It's like cruising down the interstate in your recliner.

 

I am. Since I weigh 400lbs I am also close to the ½ ton on either of my 700lb beasties. :-)
My 1989 GTR1000 (Concours in USA) has a Russell Day-Long saddle so is as comfy as your Wing, although without the HiFi and many other gadgets.
The 2007 GTR1400 (Concours 14 in USA) has a Corbin saddle so not as comfy but stupidly fast and handles superbly.
Given my size (6'4" and size 16 feet) I treat the 1400 as my "sports" bike and the 1000 as my Tourer.
Both are capable of 400+ miles days, but on the 1000 I have done 1000+ mile days.

 

Cool! I got my bike used with over 200K on it. The gadgets were nonfunctional, and I don't care. The two features that I really like still work. cruise and reverse. For getting out of a downhill parking place it's great to have reverse! It goes pretty well for something that big. I like the fact that the saddle is low enough even for a little guy like me to have both feet firmly on the ground. It has a very short turn radius for something that long, which works well for parking, but you have to be careful about that when riding. The throttle response and braking are also very pronounced. I was surprised, even though I had ridden one when they were new. I don't ride much, so even though it's been years, I haven't put many more miles on it, but at 71 years old, this will probably be my last bike. I also have a 1987 Turbo Buick Regal Limited. It's the Luxury version of the Grand National. I have done some mods to make it a bit more resistant to breaking and also faster. It is heavy at near 2 tons but is very fast for a street legal and driven car. It has all features still intact and working, AC, Cruise, Astro-Roof, power steering, brakes, windows, leather seats and a kick *** stereo. It should run the 1/4 in the 10s no problem but has no roll bar, so only allowed 11.5 and 135 by the rules. I have not raced it at the track, but used to be a notorious "Street Racer" and have wins over 10 sec cars. We did this on a very safe road, in the middle of the night, many years ago.

 

I don’t think this is correct. I had all 4 tires go down in pressure about a month ago and I received the warning while dropping my parents at the airport. I thought maybe one was low but none looked flat so drove it to the tire store and found all 4 tires at 26 psi vs 32 psi where I had it set.

 

Entirely likely you are correct and I was wrong. I have not experienced this as I have only ever had one tyre lose pressure at a time.
It sounds like the Lexus system registers a particular rolling radius for each wheel and then warns when it drops below a certain value.
That could be awkward with winter tyres as they have deeper tread so could wear sufficiently for the error to show, even if the pressures didn't change.

I did have a problem with my system when i first bought the car and I had to reset it several times until I finally changed all 4 tyres.
That got rid of the regular low pressure warning so I suspect having mixed tyre brands confused it.

 

so if you have 17 inch wheels the correct pressure is 32 but the 18 inch take 33psi
seems to me bigger wheels should take less not more
I have had little to no success with tire pressure monitor
right rear went totally flat and system never went off, just smelled burning rubber