TC Bros. Choppers USA Made Universal Hardtail Kit. The CNC Mandrel Bent Tubing is 1 1/8" Diameter Steel with .120 (about 1/8" wall thickness. The axle plates are CNC laser cut from 3/8" thick steel and have an integrated mounting tab for easy fender mounting. The axle slots are 20mm (.787"). In addition to the cross tubes offered, we also include solid cold rolled steel slugs that fit tightly into the inner diameter of the tubing for joining the hard tail to the stock frame tubes. You can determine stretch, ground clearance, width, etc. Fitment possibilities are nearly endless. Remember that since this kit is universal, you will be responsible for modifying your frame and making this kit fit and function properly. All modification is done at your own risk.