You don't need to do any of that cold setting or anything- the bike is spaced at 128- it has 47cm long chainstays- it's really easy to just slip a 130 spaced wheel in there.
I have a 1985 Trek 720 that came to me with the stock Helicomatic and I replaced the rear wheel with a 130 spaced Phil Wood 10 speed wheel.
IMG_1714 by
Dave The Golden Boy, on Flickr
Originally Posted by
tarsi
My question is, are there any options to get to a 7 speed setup and if so, what would it involve? The goal is indexed brifter shifting. I've read about using 8 of 9 and 9 of 10 cogs to fit on 7 speed hubs and would be open to any unconventional solutions such as these.
If I understand your question correctly- you want to use the Helicomatic "freehub" as a freehub for a regular cassette... That's not going to work. Not only will normal cogs not fit on there, but even though a Helicomatic is a "cassette" it's still more like a freewheel.
Your best course of action is to get a different wheel (or wheel set) either with a freewheel hub spaced for 7 speed if you wish, or a cassette hub for anything spaced at 130.
The 720 is a "lifetime bike," it's a unique and fantastic bike. Nothing you put on there will outclass the bike.
I'm running mine with 7700/7800 Dura Ace.
IMG_2377 by
Dave The Golden Boy, on Flickr
IMG_1715 by
Dave The Golden Boy, on Flickr