W245 with tyre pressure sensors

[danclyon]

So after today's MOT at the Merc franchise in Cambridge, SWMBO needs another new wheel thanks to the opposite corner now being cracked, and advisories on 3 tyres....we knew the tyres were getting low.

I want to get Falken ZE912, but the dealer cannot supply offering the awfully-quick-to-dead-but-very-grippy FK452's or Dunlops at a lot of money for the 10k miles they actually seem to last (and no the wife's last name isn't Senna!). I've had great results with the Falkens on my Audi A4 and she really liked the change they made from Dunlop OEM's - but I remembered wifey's W245 has tyre pressure monitoring.

Is there anything important here - ie is the sensor in the wheel rather than the valve? I'm mildly concerned that she might lose the tyre pressure monitoring and that's really rather important for someone semi-disabled....

Urgent calming messages appreciated folks! Tell me that I can get the tyres changed somewhere OTHER than the main dealer, as they want to skin me for over £400 for the Dunlops, when the Falkens are £240 a set and IME a much longer lasting, gripper tyre that's MUCH better in the wet.

Thanks,
Dan.

 

[npuk]

In a W245 there is no sensor on the wheel or valve itself, it uses the ABS wheel sensor to detect a loss in pressure. See Indirect section to read up on how it works: http://en.wikipedia.org/wiki/Tire-pressure_monitoring_system

 

[danclyon]

There is no sensor on the wheel or valve itself, it uses the ABS wheel sensor to detect a loss in pressure.

Now you know I thought that was the case, but after talking to the dealer and also to alloywheelsdirect they both told me the W245 uses the Beru system which is a lump that's attached to the inside of the wheel....Merc told me they couldn't sell me a new wheel without the old one to get the sensor from, and alloywheesdirect said the self-same-thing - ship us the old one and we'll re-use the sensor from that.....

D.

 

[npuk]

What year is the car? Do you get actual tyre pressures on the cluster display for each wheel?

 

[danclyon]

In a W245 there is no sensor on the wheel or valve itself, it uses the ABS wheel sensor to detect a loss in pressure. See Indirect section to read up on how it works: Tire-pressure monitoring system - Wikipedia, the free encyclopedia

No matter whether it's correct or not, that's a cracking bit of reading - thanks

 

[danclyon]

What year is the car? Do you get actual tyre pressures on the cluster display for each wheel?

It's a 2005 - first year they were made I think - registered around about November.....Don't get actual tyre pressures just a "tyre pressures are set correctly" reset mechanism...

Update: Wifey reported when she smashed the first alloy on a pothole, it took a few hundred yards for the warning to arrive in the display that the tyre pressure was low (and by low - read about 20% of what it should have been!)

D.

 

[npuk]

Same as mine then, you wont have sensors on the alloy if you dont get an actual pressure readout.

Even if you had sensors on the alloy you dont have to have the tyre changed by Mercedes. You dont need to replace the valve unless the sensor had died and needed replacing. You can buy the valve kits and sensors from places like alloywheelsdirect.

 

[danclyon]

OK - permission to swear quite a lot then!! She's got to go in tomorrow to get the new wheel - I'll ask her to ask them to show her the sensor that they have to remove from the wheel then and then ask for a discount for 2 wheels and being lied to. Huge thanks for that mate!!

 

[npuk]

Even the latest B class still uses the same system and it states in the owners manual:

"While the vehicle is in motion, the tyre pressure loss warning system monitors the set tyre pressure using the rotational speed of the wheels. This enables the system to detect significant pressure loss in a tyre. If the speed of rotation of a wheel changes as a result of a loss of pressure, a corresponding warning message will appear in the multifunction display."

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