W221 Spare Tire
#1
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2010 S 550
W221 Spare Tire
My regular mechanic said my valve stem is leaking on my doughnut spare. My tire guy says it needs a special valve stem. I didn't think the spare had a TPMS system in them? Is he just mistaken? I know the four regular tires do. 2010 S 550, 134k
#3
UK cars don't get a fifth TPMS sensor, its just a normal stem even if you get a full size wheel
the risk with a fifth sensor is the car will pick up the wrong one.... and anyway the car only understands 4 unique codes (it doesn't care which is on which location), but its only coded to see the 4 its got, so unless you duplicate one of the car's other 4 sensors it would do nothing and then if a different one had a puncture it will be running the same code in two places and throw its teddies anyway
not sure how they handle winter tyres.... on BM you can have set a and set b
the risk with a fifth sensor is the car will pick up the wrong one.... and anyway the car only understands 4 unique codes (it doesn't care which is on which location), but its only coded to see the 4 its got, so unless you duplicate one of the car's other 4 sensors it would do nothing and then if a different one had a puncture it will be running the same code in two places and throw its teddies anyway
not sure how they handle winter tyres.... on BM you can have set a and set b
#5
MBWorld Fanatic!
The valve stem for the donut spare wheel is indeed a unique item ... obtain from Mercedes dealer.
This is an item that’s a good idea to have on hand “just in case.”
This is an item that’s a good idea to have on hand “just in case.”
#6
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2008 S550 4Matic
When I replaced my factory wheels on MY2013 S550, I took the cargo tray off the trunk and put the full size factory wheel as a spare. It has tpms and I've never had any problems with reading the sensors. That was in 2013 and it's still in the trunk
#7
my bike wakes up by spinning (above 30mph) although a later one any large shock would wake it. So if its remains asleep all good. but how does the car know its unique Bluetooth code.... my car has 4 sensors coded to the vehicle each one has an independent code (and displays the pressure at each location on the cluster (TMPS high line)
Last edited by BOTUS; 11-17-2019 at 02:15 PM.