heres a how to guide on replacing a seat tube on a loop tail ripper
1)heres seat post before repair
2)remove most of seat post with an airsaw or hacksaw
3)then remove the remainder of the post from top tube and rear triangle, again use an airsaw or hacksaw,making sure
you dont remove to much!!!! its best to use a file to do final shaping
4)this is what it should look like once filed but keep checking new tube for fit
5)then its the bottom bracket to sort,i found the centre (inside old tube) and drilled and tapped a 5mm thread in frame then using a belt sander or grinder remove whats left of seat tube and old weld,i masked surrounding area with gaffer tape to prevent damage to frame
6)i made this jig out of junk from the garage to hold frame together,it fits on rear drop outs and headset,then by tightening nut at the front it pulls frame together,this will also keep frame together when being welded,as heat generated by welding can pull and distort frame out of shape
7) if you get tube from donker its slightly longer so it will need cutting to correct length,then i filed bottom of tube for snug fit to bottom bracket,then fit tube in frame,i tapped the 5mm thread in bottom bracket so i could use some threded bar (about 60mm longer than new seat tube)this screws in bottom bracket then using a nut and repair washer tighten on top of seat tube ,this will keep everything square
8)as said before heat can distort frame so better safe than sorry ,i made these bottom bracket jigs out of a couple of old bearing cups and some large washers,i welded washers to cups and used a large nut and bolt to hold them together,
once all the hard works done you will have to find a good welder,(note... make sure tube is in the right place)
9)once welded this is what it should look like
then remove jigs from frame all being well these should keep everything in the right place
