I recently bought 2 new tires for my GLK250. At the same time, I bought 4 TPMS sensors, reasoning that the old ones would run out of battery over the next few years. I'm now left with 2 brand new TPMS sensors. I could a) hold on to them for the next several years until my rear tires need replacing, or b) try to sell them to someone else who needs them. My question is, do the batteries inside the sensors discharge on the shelf? If not (or not appreciably) I'll just hang on to them, but if they do, I may as well get a couple bucks for them.

 

I would've replaced all 4, since the 4Matic system is known to be picky about tire circumference differences. A new tire vs old tire will have less revs per mile due to higher tread, so if the difference is 3% or more you could potentially have issues.

Some stores like Discount Tire run specials when you buy a set of new tires, and some manufacturers also offer their instant savings or rebates for a full set; why skimp on the only thing between you and the road surface?

As for the new TPMS, they can go on when you replace the old ones. Although I will add that mine are original and have been fine. They've gotten "rebuilt" twice, when I bought a set of tires around 90K miles and most recently when I had a new set installed the other day.

 

Thanks! I had replaced the rear ones very recently, and at the time, the shop DID replace the sensors...or so they claimed :-) Sounds like putting the ones I just got into a drawer will work just fine. Thanks!