Should tyre pressure be 35 or 40?

There isn’t a universal answer. The correct pressure depends on your vehicle’s manufacturer specification, which is usually found on a door-jamb label or in the owner's manual. For many cars, 35 psi is a common baseline, but 40 psi is only appropriate if the car’s documentation calls for it, typically for heavier loads, towing, or specific tire types.

Tire pressure must be set when the tires are cold and reflects factors such as load, speed, and weather. This article explains how to determine the right value, why it matters for safety and efficiency, and how to adjust inflation across seasons and driving conditions.

Where to find the right figure

To know the exact pressure you should use, consult the official specification for your vehicle. The main sources are listed below.

• Door jamb placard: A sticker on the driver's door edge or frame showing front and rear pressures for cold tires, sometimes with separate values for different load conditions.


• Owner’s manual: The manual may list alternative figures for different wheel sizes or load scenarios.


• Spare tire: If you regularly use a spare, check its required pressure, as space-saver tires often have different specs.


• Units shown: Some labels use bar; others use psi. Convert as needed and keep units consistent.

Always use the exact figure specified for your vehicle and tire size. If the label shows 35 psi for front and rear, that’s the target; if it shows 40 psi due to load, use 40.

35 psi: A common baseline for many cars

For many everyday passenger cars with typical loads, a baseline around the mid-30s psi when cold is common. This baseline generally balances ride comfort, handling, tire wear, and fuel efficiency, but the exact value varies by model and wheel size.

• Front and rear tires may have the same value on some models, while others require different figures for balanced handling.


• Pressure near the manufacturer’s baseline helps maintain a healthy contact patch, aiding grip in normal driving conditions.


• Riding at too low a pressure increases rolling resistance and wear on the inner edges; too high a pressure can reduce grip and cause center wear.


• Seasonal and load changes can push you off the ideal point, so recheck after loading up for a trip or changing seasons.

Conclusion: 35 psi is a widely seen baseline for many cars, but always rely on the official spec for your vehicle rather than a generic number.

40 psi: When it might be appropriate

In some situations, the manufacturer may specify a higher pressure around 40 psi (2.8 bar) or more. This is not a universal recommendation for all cars and tires; it’s specifically tied to the model, tire type, load, or use case being described in the official documentation.

• Heavy loads or towing: More pressure can help maintain a stable contact patch when the car is carrying substantial weight.


• High-speed highway driving with certain tires: Some setups call for higher pressures to maintain performance and wear characteristics at speed.


• Specialized tires: Some performance or low-profile tires are designed to run at higher pressures as specified by the manufacturer.


• Always verify with the vehicle’s manual or placard before applying 40 psi, even if you see higher values suggested by online guides or forums.

Conclusion: 40 psi is not inherently better; it is the correct value only when the vehicle’s official guidance calls for it. Rely on the exact specification for your car and tire configuration.

How to check and adjust your tire pressure

Measuring and preparing

Before you measure, ensure tires are cold (driven less than 1–2 miles in the last three hours). Use a reliable gauge and round to the nearest psi or 0.1 bar as your gauge allows.

1. Check each tire (including the spare, if you frequently use it) against the vehicle’s specified cold pressure.


2. If a tire is below the recommended pressure, add air in small increments (about 1–2 psi at a time) and recheck frequently.


3. Inflate to the exact pressure listed on the placard or manual for front and rear tires, if different.


4. Recheck all tires after inflation to confirm even readings.


5. Replace the valve caps securely after measurement to prevent air loss.


6. Record any deviations or notable changes in tire wear and mass-load conditions to monitor over time.

Regular checks help maintain safety, fuel efficiency, and tire longevity. Temperature changes can alter pressure by about 1 psi per 5°C, so seasonal adjustments may be necessary.

Summary

The answer to whether tyre pressure should be 35 or 40 depends on your specific vehicle and how you use it. There is no universal setting that fits every car. Always follow the manufacturer’s cold-tire pressure specification found on the door placard or in the owner's manual. 35 psi is a common baseline for many mainstream passenger cars, while 40 psi may be required for particular models, loads, or tire types. Regularly check pressures when tires are cold, adjust for load and speed, and ensure you inflate all tires to the exact recommended values to maintain safety, handling, and efficiency.

What psi should my 35 inch tires be?

For 35-inch tires, the recommended PSI is typically between 28 and 35 PSI for daily driving, but the correct pressure depends on your vehicle's weight and the specific tire. Always check your driver's side doorjamb sticker for your vehicle's specific recommendations, as this is the most accurate guide. For highway driving, you may increase the pressure slightly (e.g., to 32-34 PSI) for better fuel economy. 
Where to find the correct PSI

• Check your vehicle's doorjamb sticker: This sticker, located on the driver's side doorjamb, lists the manufacturer's recommended cold tire pressure for your specific vehicle. 
• Do not use the tire's sidewall pressure: The pressure listed on the tire's sidewall is the maximum pressure for the tire, not the recommended pressure for your vehicle. 

Factors to consider

• Vehicle weight: Heavier vehicles will require a higher PSI than lighter ones to maintain proper handling and a flat contact patch. 
• Driving conditions:
  • Daily driving: A pressure between 28 and 35 PSI is a common starting point. 
  • Highway driving: Increasing the pressure slightly (e.g., to 32-34 PSI) can improve fuel economy. 
  • Off-roading: You may need to lower the pressure significantly for better traction, but this is only for specific off-road situations. 
• Tire wear: To ensure even wear, use the "chalk test" to find the optimal pressure for your setup. Drive a short distance on a chalked tire and check the chalk pattern. 
  • If the chalk is rubbed off in the center, the tire is over-inflated. 
  • If the edges are worn and the center is not, it is under-inflated. 
  • You want an even wear pattern across the tire. 

Is 40 psi too much for 35 psi tires?

Yes, 40 psi is likely too high for tires recommended at 35 psi, as it can lead to a harsh ride, reduced traction, uneven wear, and a higher risk of damage. The recommended tire pressure is found on the sticker in the driver's side door jamb and is optimized for your vehicle's safety and performance. Overinflation beyond this recommendation is generally not recommended for daily driving. 
Risks of overinflating to 40 psi

• Harsh ride: The tires will be too stiff, transmitting more of the road's imperfections into the cabin. 
• Reduced traction: Overinflated tires have a smaller contact patch with the road, which can decrease grip and lengthen braking distances. 
• Uneven tire wear: The center of the tread will wear out faster than the edges because the tire bulges in the middle. 
• Increased risk of damage: Overinflated tires are more vulnerable to damage from potholes and other road debris. 
• Safety concerns: Decreased traction and a higher risk of blowouts can compromise your safety. 

When you might consider a higher pressure

• Heavy loads: If you are carrying a heavy load, you may need to increase the pressure in the rear tires, but you should always follow the manufacturer's guidelines for specific load conditions. 
• Towing: Towing can require higher tire pressure to handle the extra weight, but again, always check the vehicle's manual for specific recommendations. 

What to do instead

• Check the door jamb: The most accurate and safe tire pressure for your vehicle is listed on the sticker in the driver's side door jamb. 
• Use a pressure gauge: Always use a reliable tire pressure gauge to check your tires when they are cold. 
• Follow the recommendation: Inflate your tires to the pressure recommended by the vehicle manufacturer, not the maximum pressure listed on the tire itself. The pressure on the tire is the maximum it can hold, not the optimal pressure for your car. 

Is 35 psi good for a SUV?

30 PSI is generally typical for small car tires, while 36 PSI is appropriate for medium-sized vehicles. Proper pressure in larger vehicles like SUVs, crossovers, and light trucks falls between 35 and 45 psi, depending on their weight and size. Higher pressure levels, between 50 and 65 or more, apply to trailer tires.

Is 35 too low for tire pressure?

Whether 35 psi is too low depends on the vehicle's recommended tire pressure, which is found on a sticker inside the driver's door jamb or in the owner's manual. If the recommended pressure is higher, then 35 psi is too low, but if the recommended pressure is 32-35 psi, then it is acceptable. 
For a vehicle:

• Check the manufacturer's recommendation: The ideal tire pressure is set by the vehicle manufacturer for safety, handling, and tire life. 
• Look for the sticker: Find the sticker on the driver's side door jamb for your vehicle's specific recommended pressure, which is typically between 32 and 38 psi for most passenger cars. 
• Avoid using the sidewall number: Do not inflate to the maximum pressure listed on the tire's sidewall, as this is the maximum the tire can hold, not the recommended pressure for your vehicle. 

For a water pipe:

• Low pressure: 35 psi is considered a bit low for residential water pressure, which typically ranges from 45 to 80 psi. Anything below 40 psi is considered low, and below 30 psi is considered too low. 
• Minimum pressure: The minimum pressure required by code is 20 psi. 
• Consequences of low pressure: Low water pressure can be a symptom of a wider issue or simply a matter of your home's plumbing configuration. 
• Possible solutions: Some solutions may involve using a water pressure booster or a whole-house water pressure booster pump.