Changing to bigger tires on your car or pickup is pretty simple, but there may be some issues with the Tire Pressure Management System if your vehicle or pickup has one.
TPMS systems work on the tire pressure, not the tire size, so upgrading to bigger tires should not affect the TPMS. However, if the pressure of the new tires is higher than the set you replaced, you may have to take your vehicle to your dealer to have the TPMS system settings adjusted.
Understanding the different types of TPMS systems, how they work, and the effect that bigger tires may have will give you better insight into whether adding bigger tires would affect your TPMS system.
What Is TPMS And Why Your Car Has One
The tire pressure management system does exactly what it says; it manages the tire pressure in each tire individually. The primary purpose of TPMS is to give feedback to you as the driver concerning the inflation levels of your tires.
In 2007 and following many accidents caused by underinflated tires, the US Government passed the TREAD Act, which stands for the Transportation Recall Enhancement, Accountability and Documentation Act.
Consequently, most vehicles sold in the USA from 2007 onwards have a tire pressure monitoring system installed. The TPMS indicator on your dashboard will light up if any tires are seriously underinflated.
Why Is Driving With Underinflated Tires Dangerous
Secondly, because the tire is underinflated, there is more rubber in contact with the road, which leads to increased friction, premature heating, overheating, and possibly a full blowout of your tire- another hazardous situation, more so at speed.
Thirdly, you risk damage to your car’s chassis and suspension, and it adds significantly increased wear and tear to your wheels, brake calipers, brake lines, rotors, and fenders, which will be expensive to fix.
And lastly, driving on underinflated tires increases your fuel consumption by decreasing the tire’s traction efficiency.
Driving on underinflated tires is very risky, dangerous, and expensive, and that is what the TPMS system is there to prevent.
Should All Your Tires Have The Exact Same Pressure?
What Are The Types Of TPMS
Firstly, driving with underinflated tires reduces the level of control over the vehicle, especially at speed. In a driving emergency, you may not be able to control the car safely, which could lead to a severe accident and injury.
You have two different TPMS options, the indirect and direct systems, and each works slightly differently. As a rule, a 25% or more underinflated tire will trigger the TPMS warning light on the dashboard.
Indirect TPMS
The indirect method uses the wheel speed sensors from your car’s anti-lock braking system. The sensors measure the revolution rate on each wheel, and the computer can determine the size of the tire based on the rate of revolution.
If the sensor picks up that a wheel is moving faster than expected, the calculation determines that the tire is underinflated, and the indicator light on the dashboard lights up.
Direct TPMS
This system uses individual and independent pressure monitoring sensors in each tire that monitor the individual tire pressure in each wheel. It may even provide additional data like tire temperature readings.
This system is not piggy-backed onto the anti-lock braking system and is probably the better TPMS option.
Bigger Tires, TPMS, And The Onboard Computer
Because TPMS systems only record the tire pressure, the sensors and readings themselves are not affected if you install bigger tires. You may need to change out the direct sensors if you have them or add new ones to your new tires.
The problem often comes in with the onboard computer as the default pressure settings in the system itself may not read or accept the increased tire pressure of bigger tires. This can lead to a rather annoying scenario where the TPMS warning light is constantly on.
In some cases, you can reset the TPMS system yourself using the car’s computer if it has that functionality. If it doesn’t, then you may need to take your vehicle back to the dealership or a qualified technician for assistance.
Whether you can make this adjustment yourself or require a technician will depend on the TPMS system your car has and whether it was designed to be user-adjusted or not. If you are unsure, you can consult your owner’s manual or contact the dealership or the brand’s technical team for advice.
TPMS Is All About The Tire Pressure
There may be a lot of confusion among drivers around whether larger rims and tires will affect the TPMS, but you need to remember that the TPMS is about TIRE PRESSURE MANAGEMENT, not rim or wheel size management.
When you first get your car, the TPMS is set to the tire pressure of the tires on the car, and if you change them to bigger tires down the road, then the TPMS system will read an error if you don’t reset to the new tires’ standard pressure.’
This means that the TPMS warning light will remain on until the system has been reset and the new base pressure loaded to the system as default.
Standard tire pressure when cold should be between 32 and 40 psi in the US. So let’s say that your old tires had a base psi of 30 psi and the new tires have a base of 35 psi. Once the new tires are on, you can reset your TPMS to read all four tires at the new standard pressure.
This then becomes the default and replaces the old 30 psi pressure. If the tire pressure on any new tires drops by 25% or more, the TPMS warning light will display.
Conclusion
In most cases adding bigger tires will not affect the TPMS system; it will simply require recalibration to the new tire pressure of the bigger tires. Once this is done, you should have no issues with the TPMS warning lights coming on repeatedly.
TPMS is a valuable safety warning system, and every care should be taken when adding bigger tires to ensure that the TPMS is working correctly as your life and the lives of your family may well depend on it!
Resources
https://www.bridgestonetire.com/learn/maintenance/tire-pressure-monitoring-system-how-tpms-works/#
https://www.schradertpms.com/en/driver-education/what-tpms-and-how-does-tpms-work
