allender02

I have looked over so many forums and threads to no avail, google has not helped much either.

I am getting back into building some diy style long john/bakfiets cargo bikes. I recently finished my jig table and am looking for some doner bikes. but my issue is what sized tubing i should get for my head tube. I plan on using 1 1/8 threadless headsets since i have a few laying around, but in the end im not picky. In the past i simply cut off the bottom cup and welded that to a sleaved head tube, but id rather not go that route again.

from what ive gathered i need to look for 1 1/2 tubing with a thickness of around .045.

then my question is (if that is indeed the right sized tubing) once the bike is welded up and done, ill obviously need to take it to a shop with a reamer and facer and get that done, right. then im good?

reddog3

Since you have headset cups on hand, the easiest way to determine size would be to measure for insertion size.


Typically 1 1/8 external cups have an insertion size of 34mm. Select your tubing accordingly. Most headtubes supplied for 1 1/8 headsets are 36 or 37mm OD with wall thickness appropriate for reaming to 34mm ID.

shelgame

I think .045" wall is too thin. If you want to use 1-1/2" straight tube, you'd need to start with at least 0.083" wall to have enough material to ream out to 34mm (after reaming, the nominal wall thickness would be about 0.08").

dsaul

You may have gotten the answer you need from one of the other forums, but the best way is to just buy one of these and be done with it. OS CRMO 37.0 X 700 :: TUBES STEEL :: Nova Cycles Supply Inc. Maybe buy some of the other things you need from there to justify the cost of shipping, which is pretty steep for a single item.