XS750 (non leading axle) or TX750 tubes will slide right in!!! They are 36mm in diameter. You can then use either a 19" mag from an XS750, XS650, SR500, ETC. or you can use a wire wheel from an XS650, TX650, or TX750. I am going to be using the XS750 tubes with the mag off the same bike on my 81 XT500 project. Good luck!