Tread pattern and depth, material and size are not the only things that allow your tires to improve the driving experience. Maintaining optimal pressure inside the tires actually has many functions besides protecting the wheel. It helps prolong their service life, benefits handling and absorbs minor shocks from the bumps on the road for smoother and more comfortable driving.
Most passenger cars today have a recommended tire pressure range from 32 psi to 35 psi. But just as one size doesn’t always fit all, this range doesn’t necessarily work best for every vehicle and task. And we will discuss situations when it can be more beneficial to slightly lower the tire pressure below that guideline or inflate a bit more to get the best results.
Figuring out the recommended tire pressure for your vehicle
Before we can start going into all different ways to enhance performance by altering tire pressure, we should find what is actually recommended for your car. It can differ from the average recommended psi range, and changing it based on that value will be useless or even harmful. Another thing you should remember is that some vehicles require different tire pressure for front and rear wheels. In this case you should rely on the recommended values for each pair separately.
You can always learn what your real recommendations are by looking for a sticker on the driver’s door, consulting the owner’s manual or looking it up online. Don’t search the tire’s surface for this measurement, they always have the maximum safe tire pressure written the sidewall. Driving on overinflated tires will be far from pleasant. You will experience a noisy and rough ride with poor handling. This mistake can cost you premature tire wear and high risk of blowing a tire while driving on a busy road.
Tire pressure recommendations for a smooth ride
You can stay within the recommended range and still experience some minor inconveniences. This usually happens when tires are a little stiff and not overinflated but could use some adjustment. The safe range for most, but not all passenger cars, is about 30-35 psi for a smooth driving experience. Slightly lower tire pressure makes the wheel softer and balances out rough tires and stiff suspension.
However, you should not get too excited while deflating tires. Going below the recommended pressure level is not a good idea. Keep in mind that practically every modern car will monitor tires at all times and will notify you about an underinflated tire as soon as you lose 10% of pressure or more. Usually, going 1 or 2 psi under the recommended level is fine.
You should remember, that pressure is not constant inside your tires, it changes whenever the temperature outside shifts, when you drive at high speed or keep your cap parked overnight. That is why it is important to check the pis and adjust it if necessary when the tires have cooled down. Otherwise, the readings will be all wrong.
Take that into account when you purposefully lower your tire pressure. If you already have minus 1 psi, when the temperature inside your tires drops there will be even less pressure. Driving on underinflated tires is more harmful than if they are a little over the recommended limit. It causes the rubber to heat up more from increased friction on a larger contact patch and prompts deterioration inside and outside the tire. A tell-tale sign on chronically underinflated tire is marks of wear closer to the outer edges.
Recommended tire pressure for trucks and SUVs
Tire pressure measurements differ not only for different car models, but also for different types of vehicles and even tire sizes. So, naturally, the average recommended limits fail to accommodate this difference. Trucks are built for heavy-duty tasks like towing, hauling and off-roading, and their tires have to keep up. Larger vehicles often require tire pressure around 40-42 psi, however, you should check your specific recommendations in the manual. And for some beefy SUVs and pick-ups this number can reach even 45 psi which is too high for an average or small car.
That may also depend on other factors. The cargo weight or difficult terrain can influence the recommended limits. Usually, the vehicle’s manual will warn you if there is a need to carefully overinflate your tires before towing a trailer or hauling a heavy load inside. The load itself will not influence the pressure inside the tire, however, it will press the car closer to the ground, bending the sidewalls of your tires as if they were underinflated. Paired with extra stress from increased weight, your tires will overheat even faster, so overinflation makes sense. But you should only do it if the manual recommends it and tires can handle such pressure.
Recommended tire pressure for difficult driving conditions
If you use a custom tire pressure that is a little over or under the recommended level, you should pay closer attention to the environment conditions. “This is a rule of thumb, but assume that each time the temperature changes by 10° either way, the psi will also change by 1,” warns Oliver Brown, Data Coordinator at Wheelssize.com. Temperature rarely imitates a roller coaster but assuming you had your tire pressure adjusted in winter, it can be a little over the limit when summer arrives.
This issue is more common in all-season tires for obvious reasons. As for the people who live in the regions where summers are hot and winters are snowy and bitter, switching between summer and winter tires eliminates this problem. But don’t forget that manuals often recommend giving 3-5 extra psi to your winter tires compared to the recommended pressure for summer and all-season tires.
That said, the change of seasons also brings harsh weather conditions like pouring rains, snow and ice. Nobody has time for micromanaging their tire pressure each time the weather changes for the worse. Good thing that you don’t have to do that anyway, because increasing the contact patch or overinflating tires will not help with traction in the snow. In fact, underinflating can cause more harm than good, creating more work for the engine.
The only reason you should consider altering the recommended tire pressure is wild roads full of rocks and deep sands. Experienced off-roaders have their tire pressure hacks and often share them on forums. So, if you are new to this activity, better ask the community for their expert opinions. To paraphrase the well-known quote, extraordinary conditions require extraordinary tire pressure recommendations.