Estuche

Looking for the common wisdom of the community here. I have a 17" wheel, mini velo frame with a 120mm rear spacing. It's made of Reynolds 531. My goal would be to make it 135mm for compatibility with IGHs. The triangle is rather complex to my rookie eyes; pics from a builder can be seen here (click on the little arrows to see more pics):
https://www.instagram.com/p/B66rPrUA...on_share_sheet

I don't think cold setting it would be wise, as the frame is already 30 years old. An obvious option would be to order a new triangle; however I wondered whether it would also be feasible to replace the dropouts and/or chain-stays to achieve the same effect? If so what should I keep in mind when speaking to a frame builder?

unterhausen

interesting project. There is nothing wrong with bending 30 year old 531 in and of itself. Those Moulton rear triangles probably wouldn't be too happy about it though. I think some of the bracing would need to be cut and replaced. But it's still less than 10mm per side, it might work to cold set. But it should be done by someone that can do it carefully, not by someone with a 2x4.

Your profile doesn't give a location. If you were on the East Coast I would suggest asking Bilenky. When someone has a weird project, I think of them first. You can try asking them anyway. I have heard their leadtime is pretty long right now though. Maybe franklin frames too.

I would take good pictures of your rear triangle to send if you aren't going to be able to ask.

I would check to see how much a rear triangle would cost, that's obviously the best option

Andrew R Stewart 

Eric give good advise, as usual. I'd be a bit less concerned about setting the rear sub frames wider, but that's just me being bold and secure in my experiences. Certainly if done heavy handedly... Mere changing the drop outs or chain stays won't get you much difference without also spreading the seat stays. 15mm is quite a bit of widening BTW. I think having a new rear sub frame fabricated will cost far more then many expect! These Moulton "space" frames are joint dense, a lot of hand work when done oneoff. In fact I would be careful of who I would have build a new rear end. Someone who is enthused and not trying to get work is the better choice.

Were this my project I would first look at the IGHs with 120 or 110 spacing. I know this eliminates a lot of current offerings. Is there something about the 135 spread spec that is written in stone? Andy

Estuche

Thank you both for the advice; I got good news I think, upon double checking, my frame is 126mm! That would make cold setting safer would it not? Anything I should recommend the frame builder I'll take it to? Anything I should mention about this particular rear triangle?

Andrew R Stewart 

The 126 width reduces the amount of widening and thus the chance of damage when doing do. To what degree I can't really say. If the builder is a good they will be able to figure things out and their judgement will be led by experience of bending other frames/tubing. If the builder is inexperienced then still likely better then most other "civilians". Andy

clasher

I know some of the sturmey-archer hubs can be spaced down to 120mm, even the 8 speed model they offer is able to get down to 120mm.