Advise for new drive train?

Discuss light weight issues concerning mountain bikes & parts.

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thewatchtech
Posts: 48
Joined: Sun Jan 28, 2007 12:34 pm
Location: USA

by thewatchtech

Nearly everything in my drive train is due for replacing at the end of this season. The crankset is shot and I want to run a 1x9 anyway. Here's the current setup: Turner Flux w/BSA, KCNC K2 XC2 26/38 cranks/BB, XTR M970 derailleurs & shifters, XT M770 cassette (11-32), KMC 9spd chain.

I could use some suggestions as I've never set up a single ring on my MTB. Other than the XT cassette, everything else could go. KCNC crank/BB are 700 grams and front DR & shifter are probably 250+ together. I'd love to shed some weight in this conversion, but reliability is more important. I do cross country riding only (no DH) with maybe 6-10 races/year - no endurance stuff.

I've looked at an e*Thirteen XCX w/32 ring up front, but what would I need to keep the chain from dropping? One issue with the Flux is the distance from the lowest clamping point on the seat tube to the top of the existing 38 ring is 3+in (8+cm), so any chain catcher will have to be pretty long. Suggestions?

Thanks!
Matt B.

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TheRookie
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Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

I run 2 bikes 1x9.

Normal crankset (of your choice), replace middle ring with a single specific. To keep the chain on you'll wat to either run a chain guide or guide rings or similar, I run a lightweight bash and inner carbon chain guide.

Short cage rear mech, right hand shifter only, I run one with a gripshift and one with a Shimano ST unit, but you can keep it normal!

For 1x9, you clearly want to be running an 11-34 to maximise gear range.
Impoverished weight weenie wanna-be!
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grover
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Joined: Mon Jul 26, 2004 1:06 pm

by grover

Are you set on 9 speed? Going 10 or 11 speed will open some better options. Obviously 1x11 you could buy an XO1 drivetrain. You could also do away with a chain guide with a 1x10 setup if you get a derailleur with a clutch (SRAM Type 2 or Shimano Trail) and run a 'thick/thin' chainring such as Wolf Tooth Components or Raceface.

Raceface just announced a new crankset designed around a direct mount thick/thin ring that weighs less than 500grams.

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thewatchtech
Posts: 48
Joined: Sun Jan 28, 2007 12:34 pm
Location: USA

by thewatchtech

Thanks to you both for taking the time to reply. I ran into a buddy of mine (and fellow WW) today and found that he's running an Absolute Black single up front and been very happy with it. I have no problem with switching to 10spd so I'll either give that a try or maybe setup my old RaceFace triple with a bash guard and inner ring to see how it goes.

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thewatchtech
Posts: 48
Joined: Sun Jan 28, 2007 12:34 pm
Location: USA

by thewatchtech

Just as a followup, I put on a Raceface narrow-wide 32T single ring and X10SL chain on the existing KCNC crank and ditched the front der and shifter. The move shaved about 360g so the Turner Flux is now sub 10kg (about 21.75). I went on a race pace ride yesterday on a rough course and the chain doesn't rattle at all. What a difference! Between the chain engagement and weight loss, this bike has gone from great to outstanding. Thanks!

Matt B.

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doctacosmos
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Joined: Tue Sep 10, 2013 5:18 pm

by doctacosmos

grover, any idea what that raceface crank is called or when it's available?

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