tpms for c400 4matic in Canada
09-29-2015, 10:35 AM
#1
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c400
tpms for c400 4matic in Canada
So, this past weekend I found out the outer side of the front tire was completely bald. I checked all tires and found the front two is less than 25psi and the back tires are less than 35. However, there is no low tire pressure warning at all. Now, I talked to the service guy at the dealership, and he told me that if the monitor system is working off the ABS or something and they don't have individual sensors. so if the psi gradually decreases in PSI for all tires, it will not warn us of low pressure. Even when all goes to zero psi.
my question is... how true is that?
my question is... how true is that?
09-29-2015, 10:18 PM
#2
Junior Member
So, this past weekend I found out the outer side of the front tire was completely bald. I checked all tires and found the front two is less than 25psi and the back tires are less than 35. However, there is no low tire pressure warning at all. Now, I talked to the service guy at the dealership, and he told me that if the monitor system is working off the ABS or something and they don't have individual sensors. so if the psi gradually decreases in PSI for all tires, it will not warn us of low pressure. Even when all goes to zero psi.
my question is... how true is that?
my question is... how true is that?
There are two types of TPMS - direct and indirect.
Direct sensors are mounted within the wheel and contain a sensor and transmitter that provide a warning when the pressure in any single wheel drops more than 25 per cent from a pre-set amount. Obviously, when a tire is removed from the rim, there is no pressure, which means the TPMS has to be reset when the new or different tire is installed.
Indirect TPMS uses the sensors related to the ABS system, which measure the relative speed of the four individual wheels. Using this data, they can determine if one wheel is turning more rapidly than the others, as would be the case if pressure - and thus the rolling radius of the tire - dropped. The indirect systems are obviously not as accurate and are thus set to trigger a warning if pressure drops more than 30 per cent.
09-29-2015, 10:58 PM
#3
MBWorld Fanatic!
Canadian vehicles, at least the BMW's I owned and the MB's use indirect sensors. See the explanation from a globe and mail article:
There are two types of TPMS - direct and indirect.
Direct sensors are mounted within the wheel and contain a sensor and transmitter that provide a warning when the pressure in any single wheel drops more than 25 per cent from a pre-set amount. Obviously, when a tire is removed from the rim, there is no pressure, which means the TPMS has to be reset when the new or different tire is installed.
Indirect TPMS uses the sensors related to the ABS system, which measure the relative speed of the four individual wheels. Using this data, they can determine if one wheel is turning more rapidly than the others, as would be the case if pressure - and thus the rolling radius of the tire - dropped. The indirect systems are obviously not as accurate and are thus set to trigger a warning if pressure drops more than 30 per cent.
There are two types of TPMS - direct and indirect.
Direct sensors are mounted within the wheel and contain a sensor and transmitter that provide a warning when the pressure in any single wheel drops more than 25 per cent from a pre-set amount. Obviously, when a tire is removed from the rim, there is no pressure, which means the TPMS has to be reset when the new or different tire is installed.
Indirect TPMS uses the sensors related to the ABS system, which measure the relative speed of the four individual wheels. Using this data, they can determine if one wheel is turning more rapidly than the others, as would be the case if pressure - and thus the rolling radius of the tire - dropped. The indirect systems are obviously not as accurate and are thus set to trigger a warning if pressure drops more than 30 per cent.
09-29-2015, 10:59 PM
#4
MBWorld Fanatic!
So, this past weekend I found out the outer side of the front tire was completely bald. I checked all tires and found the front two is less than 25psi and the back tires are less than 35. However, there is no low tire pressure warning at all. Now, I talked to the service guy at the dealership, and he told me that if the monitor system is working off the ABS or something and they don't have individual sensors. so if the psi gradually decreases in PSI for all tires, it will not warn us of low pressure. Even when all goes to zero psi.
my question is... how true is that?
my question is... how true is that?
09-30-2015, 01:38 AM
#5
Audi uses indirect system and warn around 10psi drop.
So if I set them at 39, it will warn at 29.
I love this way more than pony up to another $300 of tpms sensors on winter tires/rims and one less thing to fail. I'm glad Merc uses the same system.
So if I set them at 39, it will warn at 29.
I love this way more than pony up to another $300 of tpms sensors on winter tires/rims and one less thing to fail. I'm glad Merc uses the same system.
10-24-2015, 10:33 PM
#6
Junior Member
Canadian vehicles, at least the BMW's I owned and the MB's use indirect sensors. See the explanation from a globe and mail article:
There are two types of TPMS - direct and indirect.
Direct sensors are mounted within the wheel and contain a sensor and transmitter that provide a warning when the pressure in any single wheel drops more than 25 per cent from a pre-set amount. Obviously, when a tire is removed from the rim, there is no pressure, which means the TPMS has to be reset when the new or different tire is installed.
Indirect TPMS uses the sensors related to the ABS system, which measure the relative speed of the four individual wheels. Using this data, they can determine if one wheel is turning more rapidly than the others, as would be the case if pressure - and thus the rolling radius of the tire - dropped. The indirect systems are obviously not as accurate and are thus set to trigger a warning if pressure drops more than 30 per cent.
There are two types of TPMS - direct and indirect.
Direct sensors are mounted within the wheel and contain a sensor and transmitter that provide a warning when the pressure in any single wheel drops more than 25 per cent from a pre-set amount. Obviously, when a tire is removed from the rim, there is no pressure, which means the TPMS has to be reset when the new or different tire is installed.
Indirect TPMS uses the sensors related to the ABS system, which measure the relative speed of the four individual wheels. Using this data, they can determine if one wheel is turning more rapidly than the others, as would be the case if pressure - and thus the rolling radius of the tire - dropped. The indirect systems are obviously not as accurate and are thus set to trigger a warning if pressure drops more than 30 per cent.
