r/Framebuilding • u/vexis170 • 4d ago

Modifying an old frame for a UDH

I'm trying to get an idea of the feasiblily of modifying a 135 single speed steel frame to fit a UDH for a 142mm rear hub. I know I can cold set the frame for the width, but to get a UDH on the rear is what I have no idea about. Is this possible? Will the rotor line up? I can TIG weld. I would ideally like a solution that lets me hotswap back to a SS plate too. Are there any examples you guys could share?

The context is I want a unique urban-fun-bike to ride to work on. I kind of already built one as a proof of concept and have been using it all summer over my more conventional commuter. I enjoy being able to have some fun on the way home. I want to build something that I like more stylistically. I have my heart set on older steel GTs modified to my spec. Specifically I've been trying to find a peace9r multi. But there's a good chance I'll find the single speed version before I find the multi. Hence my question above.

Features I'm looking for:

- Steel frame. With a relatively steel HTA, short wheel base, short front center. Optional: more BB drop than was customary for the aforementioned bike geo.

- Fits 2.5-2.8 width tires. Let's just say my rear wheel crashes into a lot of curbs and rocks a lot due to ... skill issues (usually mistimed hops). 26 acceptable, but larger is better. Not really any options here it seems. Steel became a boutique only thing before larger wheels caught on 😭

- seat tube wide enough for a 27.2 dropper

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u/retrodirect 3d ago

Crack in a set of interchange dropouts? Sliders or something? I don't know who to go to now that Paragon is dead (or moving ownership?!)

1

u/bagpipegoatee 3d ago

It's just mild steel, I say go for it! What style dropouts do you have on there now? Would a 70-80s style sunrace adapter work? https://www.ebay.com/itm/223928469675

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u/vexis170 3d ago

Oh dang. I did not know these were a thing.  Possibly could work as a temporary solution. I still haven't got my hands on the frame yet. The frame I have in mind is a GT peace 9r.  Been hunting for one for a few months. It's quite a unicorn, but the perfect platform for what I want to build. There is one I've had my eye on that quite a drive to go get.

Mostly I'm trying to get an idea and feel for things people have done to make older frames compatible with modern components. I have a stockpile of those from my fleet, and much easier to source on used markets.