What's the 2017 subaru wrx shift knob thread size?

The shift knob thread on the 2017 Subaru WRX measures M12 X1.25. Any aftermarket shifter or other accessory needs to match this specification, or it won't fit. While You can technically replace the shifter shaft with something that has an alternative thread size, this is way more trouble than it's worth purely for aesthetics. If You're looking to purchase an aftermarket shift knob, plenty of options exist with varying thread measurements. Therefore, You're more than likely to find a satIS Factory option, so long as You know Your specifications. Occasionally, You may even find a shifter that was "custom made" for another vehicle; it'll still fit the WRX, so long as the thread measurements match. Don't let marketing fool You into believing that it's proprietary.