Functional bikes. Not Porn not Anti

Shitty components are shitty, speed/what bike it's aimed doesn't have much to do with it.

Shimano 8 speed cassettes are cheap and reliable, most standard "9" and "10" speed mechs work set up for 8 speed, it's just a spring after all...

I can only comment on bar end and down tube shifters, both are mechanically simple and generally very reliable. The friction versions of either make set up and riding even easier.

Not sure why square taper matters. Cranks are just cranks, I'm running 9 or 10 speed rings and they work fine with an 8 speed chain.

My new Elephant 650b bike will have Claris derailleur, down tube shifter and Sora crankset (46/34 external bb), it's hard to tell any difference in performance with down tube/bar end shifter as Andy pointed out, I have the advantage that if something break, it's easy to replace with start that a LBS will definitely have without ordering it in.

The majority of new derailleur will happily go up to 32t so less need for an MTB derailleur.

My "best" bike, the Oak 650b, have Simplex down tube friction shifter, a modified Campagnolo Veloce derailleur (jockey wheel is spaced out for the wider chain), and a 13-26 8 speed cassette.

It's mechanically perfect, shift exactly when I want it, excellent feedback from the Simplex shifter and the range of the 13-26 is idea (how often do you use the 11t cog on a day-to-day basis?).

Thanks for the sound advice. One reason I want to go for 8 speed is I'm hoping fatter chain = longer life. Is there anything in this? I want my cogs and chain to last longer, basically, and be cheaper to replace when they do wear out. Also, smaller shifts on a 10 speed mech are harder to dial in, I want to be able to adjust my mech quickly on the road.

I was worried about quality because with road parts fewer speeds = cheaper, invariably. I have nothing against square taper cranks, in fact in my experience they last longer than modern external bbs.

I'm going to go with a combination of chainreaction and wiggle, where ther's some good deals to be had atm.