How does the runflat indicator work?
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2017 Mercedes-Benz C300, 2017 Mercedes-Benz GLC300
How does the runflat indicator work?
Does anyone know how the car "senses" that one of the tires lost pressure when the car has runflat indicator, but no real TPMS? Is there a device in the tire similar to a TPMS or is it through some other mechanism?
Last edited by blizzard12; Oct 19, 2019 at 04:45 PM.
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From: Perth Australia
12 C200, 12 C180, 10 Fuso Warrior crew cab, 08 RTV ute, 05 Smart Fortwo cabrio, 09 Smart Fortwo
Its always the way on most forums that someone takes the time to type how someone can google a question when they could have answered it in the same time
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It goes on the tire rotation, a flatter tire will rotate more and the speed sensors pick it up.
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It goes on the tire rotation, a flatter tire will rotate more and the speed sensors pick it up.
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From: Dutchess County, NY
2016 C300 4matic
Your car does, in fact, have a TPMS sensor on each wheel. Gross differences in pressure will be reported as a red or yellow indicator on the dashboard with a warning to stop and address the issue.
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Joined: Oct 2019
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From: Perth Australia
12 C200, 12 C180, 10 Fuso Warrior crew cab, 08 RTV ute, 05 Smart Fortwo cabrio, 09 Smart Fortwo
From my understanding TPMS and Runflat indicator are commonly confused as being the same thing, as the internet searches bring it up as the same stuff
TPMS = Tire Pressure Monitoring System will let you check what pressures each tire has and will also alert you to tire deflation, Each wheel has a sensor in the tire valve, TPMS will let you check your tire pressures in real time.
Runflat indicator will only tell you that a tyre has lost pressure, not all cars have TPMS sensors, it depends on the level of the car or options.
If it comes up in your dash as a indicator with a top view of a car, showing your actual tyre pressures of all 4 tires ( and a little yellow flat tire icon if you have a flat tire ), you have TPMS and each wheel has a sensor that relays the pressure to the car.
Pretty sure If it comes up in your dash with "Run flat indicator active, Restart with OK" you have only a runflat indicator and it uses the speed sensors to determine if a tire is flat by the rotations of the wheel and will alert you to which wheel is flat.
Generaly with TPMS your display will have the pressures in white if they are ok, yellow if a little off, and red if they need attention.
TPMS = Tire Pressure Monitoring System will let you check what pressures each tire has and will also alert you to tire deflation, Each wheel has a sensor in the tire valve, TPMS will let you check your tire pressures in real time.
Runflat indicator will only tell you that a tyre has lost pressure, not all cars have TPMS sensors, it depends on the level of the car or options.
If it comes up in your dash as a indicator with a top view of a car, showing your actual tyre pressures of all 4 tires ( and a little yellow flat tire icon if you have a flat tire ), you have TPMS and each wheel has a sensor that relays the pressure to the car.
Pretty sure If it comes up in your dash with "Run flat indicator active, Restart with OK" you have only a runflat indicator and it uses the speed sensors to determine if a tire is flat by the rotations of the wheel and will alert you to which wheel is flat.
Generaly with TPMS your display will have the pressures in white if they are ok, yellow if a little off, and red if they need attention.
Last edited by prktkljokr; Oct 21, 2019 at 07:22 PM.
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Joined: Dec 2016
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2025 GLC 300
A runflat tire is not an airless tire. Under regular use it should have in it the same tire pressure as any regular tire. If your tire runs low or out of air, then the car will alert you with a low pressure warning. From everything I've heard running these tires for 5+ years, you can run it with lower than normal pressure for a short amount of time and keep the tires. If you run these tires without any pressure though the tire will need to be replaced.
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2016 C 300 4matic Lunar blue
And, depending how much wear is on the tires on that axle, the one on the other side may have to be replaced. I understand that 4Matic doesn't play well with a new tire on one side and an old on the other. It's possible also that new tires on one axle won't get along well with worn tires on the other.
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Joined: Jan 2017
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From: Sydney
W205 C250
From my understanding TPMS and Runflat indicator are commonly confused as being the same thing, as the internet searches bring it up as the same stuff
TPMS = Tire Pressure Monitoring System will let you check what pressures each tire has and will also alert you to tire deflation, Each wheel has a sensor in the tire valve, TPMS will let you check your tire pressures in real time.
Runflat indicator will only tell you that a tyre has lost pressure, not all cars have TPMS sensors, it depends on the level of the car or options.
If it comes up in your dash as a indicator with a top view of a car, showing your actual tyre pressures of all 4 tires ( and a little yellow flat tire icon if you have a flat tire ), you have TPMS and each wheel has a sensor that relays the pressure to the car.
Pretty sure If it comes up in your dash with "Run flat indicator active, Restart with OK" you have only a runflat indicator and it uses the speed sensors to determine if a tire is flat by the rotations of the wheel and will alert you to which wheel is flat.
Generaly with TPMS your display will have the pressures in white if they are ok, yellow if a little off, and red if they need attention.
TPMS = Tire Pressure Monitoring System will let you check what pressures each tire has and will also alert you to tire deflation, Each wheel has a sensor in the tire valve, TPMS will let you check your tire pressures in real time.
Runflat indicator will only tell you that a tyre has lost pressure, not all cars have TPMS sensors, it depends on the level of the car or options.
If it comes up in your dash as a indicator with a top view of a car, showing your actual tyre pressures of all 4 tires ( and a little yellow flat tire icon if you have a flat tire ), you have TPMS and each wheel has a sensor that relays the pressure to the car.
Pretty sure If it comes up in your dash with "Run flat indicator active, Restart with OK" you have only a runflat indicator and it uses the speed sensors to determine if a tire is flat by the rotations of the wheel and will alert you to which wheel is flat.
Generaly with TPMS your display will have the pressures in white if they are ok, yellow if a little off, and red if they need attention.
