LOL
I think a d30 tube would actually sleeve inside a d60 inner C without removing the old d60 tube, might as well right? d60 tube is 2.125" ID 3.125" OD 1/2" wall, d30 2.5" OD, just turn the d60 tube in the knuckles out till it's 5/16 wall thickness and weld the 30 tubes into it. :wierd: