Drivetrain Refresh Recommendations
 

My MTB commuter's rear shifter, chain, and rear derailleur are all due for replacement. Since this bike spends a lot of time locked up outdoors at a college campus I'd rather not go overboard with the best components. I was considering X7 twist shifters, a SRAM SX5 derailleur, along with a new cassette (7-speed now). I have a few questions:

1 The bike has an older (~2001) LX rear hub (FH-M570). I believe this would be compatible with either 8 or 9 speed cassettes. Is this correct?

2 Should I go with 8 or 9 speeds? It looks like I can get the X7's in either configuration. From what I've read 9 speed systems require fine tuning more frequently for good shifts and the narrower chains may not be as durable. Is this the case?

3 Does it matter if the chain brand matches the cassette brand? Do either SRAM or Shimano cassettes/chains tend to hold up better than the other?

4 Should I worry about the chainrings if I am replacing everything else?

I'd appreciate any feedback. Thanks

Ahhh questions!
(answers?)

1. no help, someone else can catch this one?

2. I'd say go with 9, gives you a smoother range across all gears. And don't worry about chain wear.

3. Nope, I'm pretty sure that chain brand doesn't matter so much (unless its campagnolo). I happen to like SRAM chains a little more. Part of the reason for that is they are easier to install.

4. If the chainrings look worn (ie, hooked teeth) then yes, I'd replace them. Otherwise, don't worry about it.

question for you:

why do you want to go with twist shifters?

What is wrong with the shifter and rear der that they need replacement? Both these compnents are very robust and usually last a long time. If they work, but are a little sloppy, I would start with a chain and cassette, clean and adjust the der and shifter, possibly re-cable and see if that fixes the problem.

The bike has Grip Shift Xrays now. The black plastic sleeve with the index bumps broke apart allowing the rear derailleur to wander between several gears. The Alivio rear rear derailleur won't get the chain to the smallest gear on the cassette. I can bump it with my hand and it will go. I was thinking the spring is stretched or the pins had worn since it's not pulling the slack out the the shifter cable when it won't go over for the small cog. These parts had been used almost daily for about 4 years so I didn't think it was unreasonable for them to be worn out at this point. The chain is "12 1/16-"12 3/32.

I was going with twist shifters because I liked the simplicity. The 1:1 ratio of the SRAM system seemed like it would give the shifter better control over the position of the derailleur. Being able to make small adjustments to the front is also nice.

An 8 or 9-speed cassette won't fit onto your 7-speed hub.

When I searched the part number it looked like it would accept a newer cassette:
http://www.sjscycles.co.uk/product-S...e-Hub-1610.htm
Is this not the case?

It took a shim for the 7-speed to fit properly when it was installed.

Yes, it will work with an 8/9/10 speed cassette (or a seven speed with a spacer).

If it were me, considering the cost and your goals for the bike, I'd go for eight speed Shimano with trigger shifters, something in the Alivio or Deore line. Nashbar has had their Deore rear derailleurs on sale for $17.99 recently. Properly adjusted, Shimano eight speed (or nine speed, etc. for that matter) will shift as smooth as butter. No fussiness at all.

Won't the OP need a new freehub? It is my understanding that 8/9 speed requires a different (longer) freehub body.

Regards, Mark.

The OP mentioned the spacer to make the 7-speed cassette fit, so it is actually an 8+ speed freehub.