The winter bike I am building up has a full Shimano 105 groupset dating from the late eighties / early nineties. Its in pretty good condition and has index / friction downtube shifters. My Viner road bike has a mish-mash of old (pre-tri colour) Shimano 600 and newer 105. It’s okay, but the drive side shifter is a bit shit and sometimes slips under power and it’s looking a bit worn and ugly.
Am I wasting my time swapping the group sets over (except for brake levers) from one bike to the other? I know that 105 isn’t mind blowing, but it’s be nice to have a complete matching groupset on my “nice” road bike.
Nice that you are using what have, but having Sti shifters is definitely an upgrade and you won’t go back. As discussed, new shimano sora or tiagra are actually pretty good these days, and can be gotten quite cheaply.
It shouldn’t, given that 9speed shifters will move a normal shimano mech 4.25mm and 8sp cassettes are spaced at 4.8mm.
Use 9sp shifters with an old DA mech (i.e 7/8sp) and it’ll move 4.8mm - perfect.
Besides, if you have a wheel that will take an 8sp cassette, it’ll also take a 9sp cassette, so why kludge?
However, 8sp shifters and 7sp cassettes do index well, and old 7sp wheels won’t take 8+sp cassettes as they’re narrower.
Back to JLN’s query, go for it, you’re moving from a mix of 6sp (friction? Pre 6400 is either 6sp SIS/friction or 5sp friction) gear to non shagged 7sp (If indexed) gear. Does the wheel take a cassette or a freewheel? If cassette, 7sp are still available, but you’ll have to hunt for a non 11-34 megarange, and your freehub may not take an 11T depending on its age. If freewheel, leave it, and run the new stuff in friction.
I’ll be swapping the wheel set over as well. The Repco came with semi-decent Araya’s laced to 105 hubs, so everything should match nicely. I cleaned up the rear cluster and it looks fine. The only reason I’m not swapping the brake levers over is because the hoods with the 105 are white and pretty gross and the levers I have at the moment work fine and the bars are all taped up.
The 105 DT shifters can be switched from indexed to friction, so I’ll have a play and see how I go.