If you can, we highly recommend not using valve extenders when using a TPMS. This is because valve extenders create an additional issue point. They have been known to cause leaks, which can lead to a blowout, as well as no signal errors (see Pressurized vs Non-Pressured Extenders).
Straight valve stems are recommended for safely using any TPMS. We recommend taking a look at YourTireShopSupply.com's dually valve stem kits (link). Other suppliers will also carry similar dually valve stem kits. Using these kits is the safest way to protect your tires from valve stem related issues.
If you have to use a valve stem, we highly recommend straight metal valve stems. These type of valve stems can be altered by your tire dealer to correctly bend into place. When being bent, please instruct your tire dealer to provide enough room so that the TireMinder transmitter does not rub against the tire rim. This will damage both the transmitter and your rim.
Braided steel valve extenders are not recommended. They cause the most leaks, the most tire pressure and signal loss alerts, and the most overall headaches. This is due to the fact that many of they are not consistently pressurized, which means that they only pressurize for enough time to receive a gauge reading. This will cause pressure and signal issues with your TireMinder TPMS. The valve extender itself can also come loose, causing a blowout or additional damage to your transmitter and rim.
Never use rubber or plastic valve extenders.