Hey Mike - these are my favorite and come in 1 1/2":
http://www.ballisticfabrication.com/...mp_p_1467.html
or
http://www.trail-gear.com/miscellaneous
Brett wanted to use exact 1 5/8" O.D. (DSE size) to do the metal finish work, so I got these:
http://www.camburg.com/store/fabrica...t-tube-clamps/