>>1938159Not him but I mostly agree with you. 3x9 or 2x10/11 is usually the way to go.
>There are zero benefits to choosing 7/8spThere are though.
7 speed indexing is more forgiving because the spacing between the cogs is wider and the shifters pull more cable for each shift.
It's very easy to bend your hanger while touring and a bike living outside in all weather is also likely to develop some fucky resistance in the cables.
On 7 speed bikes you can satisfactorily align a bent hanger with a crescent wrench, but the more speeds you go, the more finicky it gets.
Far more nice 7 speed shifters will also have a friction mode for quick damage fixes and compatibility on repairs. I run 9 speed Dura Ace on my tourer, and that has a friction mode, good luck finding those though. Whereas 7 speed downtube shifters, and thumbies, are ubiquitous. Because your shifters are more likely to have a friction mode, and because you can put your 7 speed cassette on most any other hub, and in a pinch, use 7 speed hubs, including cheap freewheel ones, (common) the compatibility is better.
Cost. 7 speed chains and cassettes are the cheapest. I don't think it's really significant but they are cheaper.
The downside is your cassette options are pretty meagre. The 12-32 spd sram one is the best, and that's not really wide enough for anything serious. You're most likely going to find 11-28s, but even that is alright with a low bailout triple, 22, etc. For more chill touring, it's great. As for availability, they're widely available.
In real terms if you have money for a custom touring bike you should probably go something more modern and you'll get better gearing from it, but more forgiving indexing and friction mode shifters are both serious benefits, and decent 7 speed era bikes are god tier for budget tourers if you are lucky enough to have a good one available to you. You also may not want to spread a 126mm frame and stress the seat stays.