What happens to the system if you change the wheels?

Scott3:

 

Just checked the voltage on mine. They are all in the 2.97 -2.98V range (apparently 3V is full and 2.6 - 2.7 V requires replacement) - Was expecting much lower on a 2022 car (perhaps mine were replaced prior to my ownership).

 

 

 

AFAIK the voltage decay curve is flat with a steeper drop off at end of usable  of life.

I've used internal factory sensors on a RAM truck I bought in 2015. I considered them a superb safety feature - and they enabled me to manage a slow leak on an insanely wet & muddy & dark 4 hour stretch of the Dempster Highway.  I was in love with them, that day !

I looked at getting four of the battery-powered external (screw-onto the valve stem) units for a dual-axle caravan I towed over the next few years, but they were quite dear (with the separate read-out screen) and I didn't talk myself into it.

I hadn't realised that the VW-type ABS (indirect) systems had been developed. It seems like they can be useful to detect and warn against a flat - (ie: a 25% pressure drop), but are not precise enough to help in keeping your tyres tuned up for best mileage/wear over hot/cold temperatures. 

It looks like the internal sensors last 7 to 10 years - at which point you just replace all of them (best done at the time you do your tyres).

Well I’ll be.   My bad, I had no idea there was a plastic sensor attached to the bottom of the tyre valve.

Goosey:

 

It’s all these non “traditional Japan”, electronics in vehicles that’s a sleeping giant in terms of automotive diagnostics.

im sticking to traditional Japan….the parts market is much more reliable, cheaper and people know how to repair them (ford, mazda, Honda, Toyota, Nissan and their siblings and extended families).

 

Japanese cars aren't immune.

mudguard:

 

What happens to the system if you change the wheels?

 

From what I can ascertain you would need to have new compatible sensors on the valve stems and then use a scan tool to recalibrate the new sensors & 'link' them to the car's computer system. I guess if you were replacing just the tyre then you could keep using the existing sensor/valve stem setup, providing it doesn't get damaged.

Basically a lot more time & expense for a feature of dubious (or occasional) use IMO.

Goosey:

 

Senecio:

 

The sensors are usually built into the valve so it’s a tyre off, new valve and sensor, remount and balance tyre job. Something that I would try to put off for as long as possible. 

 

 

err, maybe not in standard cars… what you speak of may be in super high spec high end cars…not standard ranges. 

 

the bog standard TPMS works by having a sensor in the wheel arch usually just above the mud guards. It’s doing some math to work out the wheel spin and size and shape of tyre to get a pretty accurate read of pressure.

 

There is a guy on here @RUKI who may be able to help you out.

https://www.geekzone.co.nz/forums.asp?forumId=162&topicId=323080

Goosey:

 

Senecio:

 

The sensors are usually built into the valve so it’s a tyre off, new valve and sensor, remount and balance tyre job. Something that I would try to put off for as long as possible. 

 

 

err, maybe not in standard cars… what you speak of may be in super high spec high end cars…not standard ranges. 

 

the bog standard TPMS works by having a sensor in the wheel arch usually just above the mud guards. It’s doing some math to work out the wheel spin and size and shape of tyre to get a pretty accurate read of pressure.

 

I don't consider my Ford Escape to be a high spec, high end car. Yes, there are cars that use wheel speed differential to estimate a flat tyre but the OPs car and many others do in fact have pressure monitoring values inside of the tyre.

clicknz:

 

mudguard:

 

What happens to the system if you change the wheels?

 

 

From what I can ascertain you would need to have new compatible sensors on the valve stems and then use a scan tool to recalibrate the new sensors & 'link' them to the car's computer system. I guess if you were replacing just the tyre then you could keep using the existing sensor/valve stem setup, providing it doesn't get damaged.

 

Basically a lot more time & expense for a feature of dubious (or occasional) use IMO.

 

Depends on the car model.

Brands like Toyota, Honda & BMW require either a scan tool to enter the new sensor ID's to the vehicle (or a tool to clone the old sensor ID's to the new sensors).

My tesla, the owner can easily do it themselves via the service menu of the touch screen.

Stellantis, Hyundai auto group etc, will auto relearn. No intervention required, just replace the sensors, and the car will pick the new ones out after a decent chunk of driving.


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On the value of TPMS, note these are primary a safety feature, and are mandated on modern vehicles in a lot of places.

Real world rates of running on dangerously underinflated tyres roughly half when the car has a TPMS system (under-inflated tyres are more prone to hydroplaning, will cause worse handling, and also wear faster, and cause increased fuel use).

And running on a tyre with a leak (if undetected), can lead to a blow out and potentially a loss of control as a result. TPMS dramatically increases the odds that the driver will become aware of the issue before the tire gets to the failure point.

It's just a pity they are built as disposable parts, at put internally to the wheel. If it was an easy job to swap out 4x cheap coin cells every 5 years, it would be a lot more consumer friendly. 

clicknz:

 

mudguard:

 

What happens to the system if you change the wheels?

 

 

From what I can ascertain you would need to have new compatible sensors on the valve stems and then use a scan tool to recalibrate the new sensors & 'link' them to the car's computer system. I guess if you were replacing just the tyre then you could keep using the existing sensor/valve stem setup, providing it doesn't get damaged.

 

Basically a lot more time & expense for a feature of dubious (or occasional) use IMO.

 

Ah I more meant putting new wheels on and leaving the sensors out all together? ECU has a wobbly and leaves you with a permanently illuminated engine light?

I've done half a million kms in the past decade and managed to cope without sensors. That said I was pretty retentive with checking anyway giving the volume of kms. 

Scott3:

 

Depends on the car model. 

Stellantis, Hyundai auto group etc, will auto relearn. No intervention required, just replace the sensors, and the car will pick the new ones out after a decent chunk of driving.


On the value of TPMS, note these are primary a safety feature, and are mandated on modern vehicles in a lot of places.

 

Real world rates of running on dangerously underinflated tyres roughly half when the car has a TPMS system (under-inflated tyres are more prone to hydroplaning, will cause worse handling, and also wear faster, and cause increased fuel use).

 

And running on a tyre with a leak (if undetected), can lead to a blow out and potentially a loss of control as a result. TPMS dramatically increases the odds that the driver will become aware of the issue before the tire gets to the failure point.

 

It's just a pity they are built as disposable parts, at put internally to the wheel. If it was an easy job to swap out 4x cheap coin cells every 5 years, it would be a lot more consumer friendly. 

 

I can confirm that my RAM (Stellantis) just happily relearned the positions each time I rotated the tyres.

Apparently a fair amount of research is being done to replace the battery function with a kinetic source of power (use of the tyre's rotation to generate sufficient power).
I would have expected that to be a pretty simple problem - but seemingly not.

I'm impressed with my Hue Tap/Dial switches (for my house lights) which take the kinetic energy of my finger tapping once on the switch (or rotating the bezel) to send a Zigbee 2.4 GHz transmission to the mesh.
Zero battery and it just works every time. Brill ! 

Scott3:

 

Depends on the car model. 

Stellantis, Hyundai auto group etc, will auto relearn. No intervention required, just replace the sensors, and the car will pick the new ones out after a decent chunk of driving.


On the value of TPMS, note these are primary a safety feature, and are mandated on modern vehicles in a lot of places.

 

Real world rates of running on dangerously underinflated tyres roughly half when the car has a TPMS system (under-inflated tyres are more prone to hydroplaning, will cause worse handling, and also wear faster, and cause increased fuel use).

 

And running on a tyre with a leak (if undetected), can lead to a blow out and potentially a loss of control as a result. TPMS dramatically increases the odds that the driver will become aware of the issue before the tire gets to the failure point.

 

It's just a pity they are built as disposable parts, at put internally to the wheel. If it was an easy job to swap out 4x cheap coin cells every 5 years, it would be a lot more consumer friendly. 

 

I can confirm that my RAM (Stellantis) just happily relearned the positions each time I rotated the tyres.

Apparently a fair amount of research is being done to replace the battery function with a kinetic source of power (use of the tyre's rotation to generate sufficient power).
I would have expected that to be a pretty simple problem - but seemingly not.

I'm impressed with my Hue Tap/Dial switches (for my house lights) which take the kinetic energy of my finger tapping once on the switch (or rotating the bezel) to send a Zigbee 2.4 GHz transmission to the mesh.
Zero battery and it just works every time. Brill ! 

My (aftermarket) TPMS system has valve cap sensors.  I've never understood why that isn't the solution for OEM.  I've had the iCheck 10-sensor system on the two vehicle and boat  trailer for a few years without any problems.  Having a separate display is a bit clunky.  I'd prefer something Android Auto integrated but I haven't found anything suitable on the market

MikeAqua:

 

My (aftermarket) TPMS system has valve cap sensors.  I've never understood why that isn't the solution for OEM. 

 

Best Guess: Exposed sensors are more prone to damage & theft... On a global scale, more vehicles face ice & slush & salty water than ours do in NZ. Valve stems are also exposed to gravel & rock damage. External TPMS sensors are usually recommended to be fitted on to metal valve stems instead of the otherwise better (more flexible & damage-resistant) rubber stems. 

So while easier & cheaper to maintain (for a long-term owner), external sensors would probably occasion more OEM claims within the car's warranty period.