A couple of weeks ago, I got my new 2017 Grand Cherokee Altitude. In the first few days, I was checking the gauges and settings, and one morning, I saw that the tire pressure monitors showed the tires at 43-46-46-46 psi. I didn’t think much of it, but I wanted to add air to make them all the same.
Today, I finally looked at the door stickers and saw they recommend 33 psi for the front tires and 36 psi for the rear. I’m not sure why the dealer inflated them so much, but I plan to let some air out until I reach the recommended levels. Before doing that, I wanted to check here to see what others think. I drive my Jeep about 70 miles a day on the highway and only use some bumpy dirt roads to get to my house, so I don’t plan to go off-road.
Also, I’m not very familiar with the tire pressure monitoring system, and I’m worried that lowering the pressure from 46 to 33 might turn on the “low tire” light.
They pump up the tires too much at the factory for shipping. The dealer is supposed to set them to the right pressure when preparing the vehicle, but many forget this step. Start with the pressure shown on the sticker inside the door, and then adjust it to what you like.
The lowest acceptable pressure is around 29-30 psi. If it gets too low, you usually have to inflate it to 36+ psi and drive a few miles to reset it. After that, you can adjust it to your liking.
I’m sure others will join in, but a good starting point is the pressure listed on the door sticker. Sometimes, you may need to inflate the tires a bit more to keep the check engine light off.
Thanks for the advice. I put 36 in the back and 33 in the front, per the door sticker. I had to drive maybe a 1/2 mile to get all of the new psi to register, but so far so good.
Check the tire pressures on the side of the tire. The pressures on the sticker are more for comfort while driving. I had the same issue when I got my new Trailhawk a few weeks ago; the tires had 44 psi in them, but the sticker said 33 psi. The tires showed a max load capacity of 51 psi, so 44 psi didn’t seem too high. I still lowered it to 38 psi.
The pressure on the sticker is the recommended level for the original tires to handle the maximum load and wear evenly. The tires can hold more weight at higher pressure, but the WK2 isn’t designed for that extra load, so it’s not necessary unless you’re off-roading or want the centers of the tires to wear out faster than the edges. You can usually lower the pressure by 1 or 2 psi for comfort and lighter loads, but comfort is different for everyone. I personally feel better with a couple of psi above the sticker pressure.
Be careful about tire pressures lower than recommended by the manufacturer. The Explorer/Firestone tire debacle may have been related to tire under-inflation, overheating causing tread separation.
On my WK-1, I usually use the standard 33 psi. However, if I’m driving at high speeds for a long trip, I inflate them to 37 psi. The higher pressure helps keep the tires cooler, especially in hot weather.
Also, for anyone using LT-rated tires, like BFG all-terrain tires, on these Jeeps that originally came with P-rated tires: those LT tires need much more pressure because they’re heavier. If you keep them at 33 psi, they will be under-inflated and get too hot. They need to be between 45-50 psi.
LT tires have a higher load rating and are strong enough to handle higher pressure. Their sidewalls are stiffer. Because of this, they can wear unevenly on a lightweight passenger car unless you put in enough air to keep the tread flat. Most people here use 40-45 psi. Some even do a chalk test to check for even wear.
The tires are inflated too much when they leave the factory (over 40 psi). It seems like the dealer should have let some air out to match the recommended tire pressure before giving you the keys.
I wanted to let everyone know that after lowering my tire pressure to the recommended level, the sensor has been working fine. Plus, I’ve gained 0.5 miles per gallon in gas mileage.
I’m a little nerdy and have been tracking how much the Auto Start/Stop function saves me by checking my mileage each time I fill up. It went from 21.9 to 22.4. I thought tire pressure might help, but I didn’t expect it to make such a big difference!
Lowering tire pressure might actually reduce miles per gallon (mpg). Some people trying to save fuel pump their tires up higher to get better mileage. When I got my 2017 Limited, I noticed my mileage slowly improved over the first few months, probably because the engine was breaking in.
Your tires must be different from mine since my door sticker says the pressure should be 36 all around.