I had to look up the ST model. It comes with 27.5'' wheels, which I presume it's what you have, and I presume the tires are no more than 2.6'' wide. There are a few things to know before replacing the fork. One, is fork spacing. You can measure it with the wheel on, but best to measure it with the wheel off. All bikes use metric spec fork spacing, and it's probably 100 or 110mm. While you have the front wheel off, check the front axle diameter (it should be 9 or 10mm). Next, measure steerer tube length, which will probably be 7'' to 9''. Your replacement fork should have a similar length steerer tube. Also, measure the crown-to-axle distance. Armed with this knowledge head over to eBay, or to your local bike shop. For 100mm spacing, most old school 29er suspension forks should work if other measurements are correct. A Rock Shox Recon should be a good choice with its pneumatic preload and rebound adjustment.