Drivetrain advice

[bjf]

I'm building an entry-level hybrid for a friend. She'd prefer grip/twist shifters, and SRAM has a bunch of inexpensive shifters in 7, 8, and 9s, so I'm looking at those. I have a pair of 10s wheels for this project, but I'm assuming they can be used with appropriate spacers. For the drivetrain, here are my questions:
1) What are my best derailleur options in 7, 8, 9? I'm looking for pretty cheap, reasonably light, reasonably good functionality.
2) Can I use a 10s crankset? I'd like 50/34, 165mm, same parameters as above.
3) I know I'll need an appropriate cassette, but it looks like Harris has those, at least in 7 spd.

Ideas/ suggestions welcome.

[chiasticon]

not your direct question but a comment/question: has your friend ridden grip/twist shifters a decent bit? I ask because I went through this with my wife with an entry level bike. she didn't ride much growing up and had never really had a bike that shifts. she rode the twist shift hybrid at the LBS and liked it but then later once she'd ridden it a bit, I had to swap the shifters to click ones because she kept mis-shifting with the twist ones. not sure if it was a learning to shift (at all) thing, a tactile feedback thing, or a wrist/hand strength thing, but they didn't work for her. got on much better with click ones.

just throwing that out there, so you don't have to build it twice

[ColonelJLloyd]

Don't bother with 7s. 8s and 9s fits on 10s freebub without a spacer. You can use your 10s crankset

[Ken Robb]

I have 7 speed twisters on my bikefriday. They work ok with its flat bars but I prefer bar ends on drop or moustache bars.

[benb]

I forget how many gears there are but I tuned up my in-laws hybrids, they had SRAM X.7 stuff I think (they were 8 speed maybe?). They are not that old.

In any case I was pretty impressed with the stuff, I got those bikes shifting pretty much as perfect as if they had something like Ultegra or XT and they have never complained about them again.

They have triples, and the triple worked really well once I had adjusted it. I have SRAM X.0 (9-speed) on my MTB and there wasn't much difference in shift performance. (Who knows how they perform with a ton of power going through the chain of course.)

I'm no fan of twist shifters though.