I have a 1987 Cannondale SR500 which I am considering upgrading to a more modern drive train. I am leaning towards collecting Shimano 105 parts from eBay with a triple chain ring. I have various things I need to figure out. For the moment I want to understand how to route the cables beyond the down tube on up to the combination shifter/brake levers on the bars.
Any ideas?
How do you measure this spacing? What is on the bike is a 6 speed SunTour with a Maillard 400CX sealed mechanism 36 hole hub. When I measured the spacing between the inside of the frame drop outs I only get about 107 mm. Since that is so much less than what you suggest, I suspect I am not measuring the right thing.
I don't know why I got such a small number before. I clearly get 126 mm. So I can look for a 7 speed freewheel but I imagine I need a threaded one.
Yes, you would need a freewheel and not a cassette. If you get a shimano or "shimano-compatible" freewheel, it will work with shimano 7 spd shifters. You might be able to use an 8 speed shifter with one click locked out. But I'd do a little checking on compatibility between 8 and 7 speed stuff. I can't remember what all works with what.