It is made to roll. Don't over tighten your chain (3/4-1" of freeplay) and it should pose no problems. You may want to add a set screw through it into the frame if your frame is small where it bolts on.
I hate to cough up an old thread but maybe the correct SKU numbers for the parts will help someone looking for the tensioner.
Baja Motorsports Chain Tensioner Assembly
SKU 551023899 $9.98
Baja Motorsports Spring Tensioner
SKU 551025499 $2.98
As misteright says, the #551025499 Spring is really a little too light to apply correct tension. Any torsion spring that's a little heavier will do the job a little better. Depending on your mounting method, you might need a slightly longer leg on one end or the other of the spring.
Be very careful with the part name and number. I drove to another store to get the tensioner and when I got there they only had the spring. It might be worth it to go ahead and get the spring to have a pattern to bend a heavier spring to fit.
The TSC website shows the parts available online or in-store.
have you seen mine! I used a shimano brake arm that had a round torsion spring built within the arm made a new bracket with a single hole for bolt to pass through and several small holes around it for adjustment of spring tension. kinda like whats on a caliper style v brakes with a post mounted on the frame and the small plate with the three holes for the spring.(you know what Iam saying) and then grooved a skateboard wheel for the chain guide. just my own way of making something better that worked for me. FileStyle