Modificatie on a lugged frame

I’ve been asked to modify a lugged frame to discbrake 142mm and bigger tires. When I took on the job I wasn’t aware that it’s lugged. Taking off the rear triangle, leaves me with the little lugged stubs.
My plan now is to hole saw a bit of the stubs and braze on an extra bb shell, to use as a yoke, and land the new chainstays on the second bb shell.
Any thoughts on that? Thanks

Why? Just take the lugged BB off, fillet braze on the plain one and fit the stays as normal.


Yeah, that seems like a lot of work and I’m not sure I understand the motive. Just cut the stub chainstay lugs off and braze/weld the new stays on. You might need to patch/fill some of the holes on the BB shell but that’s going to be much easier and you’ll end up with a nicer solution.


Thanks, yes to much thinking. And didn’t see the obvious solution

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What are the new specs of the modification? Same tire clearance? Flatmount or ISO?

If @stevenshand’s solution does not work, you could consider replacing the BB and Dropouts with larger diameters (T47 and Paragon 1.5in round) to give you more room to chop the stays. But that is a lot of work…

It might be easier to construct the rear triangle from scratch (ST, CS, SS, BB) and then braze the front triangle onto it.


Bigger tires , 700X42 and flatmount.
Also thought about removing the ss and dropouts and replace with paragon tab flatmount. . But it gets very long that way

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It’s not that hard to unbraze the old chain stays from the shell. Just bend up some new stays. I’ll be in AMS this month at Lester’s if you need a pep talk.


Thanks for the advice. Followed Hahn his route.
Melted out the old stays and fitted in new ones. Even managed to recycle the old seatstays


That’s dope AF!

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Very cool to see! thanks for documenting it!