friction shifting and derailleur quality
 

If you want to use bar end shifters mounted on Paul Thumbies as friction shifters, would it really matter that much if you went from Shimano Alivio to Deore LX? I mean, can the difference be only noticeable when in indexed mode?

Also, will a 9 speed rear derailleur travel farther than an 8 speed derailleur? I mean, if your spoke protector breaks, would there be a chance that a 9 speed derailleur on an 8 speed cassette could go too far and hit your spokes?

Is there any chance an 8 speed chain could rub against the sides in a 9 speed derailleur?

if it's setup properly, there will be no problems.
look at the various help websites like parktools and sheldon brown to set it all up properly.

Does anyone know if there is a button or switch or something on a Deore LX rear derailleur to switch from index to friction? Or is it just automatic?

The derailer doesnt know who or what is pulling its string.

Shimano's bar end right lever is where the index or friction change is.

9 speed goes on the same 130 wide hubs as 8 speed

it's a compression , thinner cogs and closer together .

the only thing to watch out for is bottom or top pull.

You can friction shift just fine with the crappiest derailleur in the world, as long as it's aligned okay.

There's really no such thing as 8spd or 9spd Shimano derailleurs; they all work the same except for some Dura-Ace ones. 9 & 10spd ones will have thinner jockey wheels IIRC, but if you want to use one with an 8spd chain you can just shim the cage out. Derailleurs have limit screws to prevent them moving too far - dork discs (spoke protectors) are for people who can't adjust them.

Well, thanks. Nice to know and very re-assuring.

lol at dork discs. hahah

Most derailleurs don't care as the "brains" of the operation are at the shifter and a Deore LX will probably be a little crisper than an Alivio and both are index compatible if one goes that way.

Both will shift 8 speeds just fine and for the money the Alivio is a good deal as they seem to take a lickin' and keep on tickin'... I got tired of waiting for an Alivio to die so I could "upgrade" it although the upgrade to the XT did improve the shifting somewhat.

Front derailleurs are much simpler and even the cheapest front d will usually do a good job and better usually just means lighter.

Yeah, when it comes to front shifting, the derailleur isn't a big factor - lift pins on the big ring are what you want.