Reply to thread

Message: <blockquote data-quote="NXR71" data-source="post: 23949" data-attributes="member: 6892">For vehicles of 10,000 lbs GVWR or less the tire pressure is governed by FMVSS 110, a Federal Motor Vehicle Safety Standard governing the selection of tires and rims to avoid overloading of the vehicle. The pressures shown on the sticker are not just something the vehicle manufacturer pulled out of their nether regions and incorrect tire pressure stickers can and have triggered a federal recall. Remember the Ford Explorer tire fiasco and associated deaths? That's why it exists.So why the difference between the older 17"-equipped wheels and the 2025 with 17" wheels?One thing "tire outsiders" may not know is that essentially ALL tire manufacturers use the exact same tire load inflation load chart for the same tire size. That's why the tire pressure sticker only lists sizes, not make and model of tire.The load inflation chart lists how much weight a tire can safely support at a given pressure. Because it's the air pressure that supports the weight, not the rubber. The rubber just holds the air in.Lowering the air pressure to improve the ride is almost always a fool's game because you run the very real risk of overloading the tire and impairing the handling, resulting in blowouts. Remember the Ford Explorer tire fiasco and associated deaths?IF you know the particulars of how a tire was selected you can safely lower the tire pressure IF you select a pressure for the tires based on the tire manufacturer's load inflation chart and IF you know the actual weight imparted on each tire through the use of a four-corner weighing. That's a lot of IF's plus you come closer to triggering the TPMS (tire pressure monitoring system) warning system because the TPMS is programmed based on the sticker tire size and the sticker pressures.So each tire of a given size, regardless of who built it,  will support the same weight at the same air pressure.A close look at the stickers posted above shows this:First sticker: 235/65R17 Load range HSecond sticker: 235/55R19 Load range H17" diameter wheels (rims) versus 19" diameter wheels (rims) plus different-sized tires (obviously).Someone with a pre-2025 would need to post their sticker showing the pressures required in their 17" wheels for a valid comparison.Bagbyjw posted some text for a 2022 LS but not a pic: 225/65R17, not 235/65R17225 versus 235 is a big difference so I don't know if that is a typo or accurate. If it is accurate then GM changed to a different size tire for the 2025 with 17" wheels and that's why there is a pressure change on the sticker.Interesting factoid: A tire that is under-inflated by a mere 20% is considered flat, not under-inflated, and susceptible to internal damage.For a tire that should be at 35 PSI it's considered flat at 28 PSI.For a tire that should be at 41 PSI it's considered flat at 33 PSI.The TPMS light is based on those percentages, not some "OK, you can safely drive at this pressure for hundreds of miles." If you do, you have just significantly increased the chance of tire damage causing a loss of all air and needing to replace the tire rather than just adding some air.[ATTACH=full]2621[/ATTACH]</blockquote>

Verification