It is a nice tight fit, no wiggle room. I took it for its first ride (about 25 miles) And nothing came loose, cracked, or broke. I put accelerated hard, and it seems fine! The only thing was the motor vibrated when it hit about 25mph, and when it hit maximum speed (30-35mph) it stopped. Could be a loose magnate, I tightened the axel nut some more, but have not ridden it to see if it fixed it.Should be a near interference fit. Best case is too tight to fit without a few light passes with a file to get it to go on. Throw all of your other cautions out the window if your torque arms aren't tight. I have a less than ideal fit on one side with my Grin torque arms so I jam a small piece of straight razor blade in between the axle and torque arm as a shim which has worked well.