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CX Drivetrain Clarity(9 posts)

CX Drivetrain Clarityeppster
Aug 14, 2002 6:25 AM

So I finally pulled the trigger on a new CX frameset - partially built (Kelly Knobby Cross). I've been getting static however on how to spec the drivetrain.

Here is what I've ordered up:

Front Der: LX
Rear Der: XT short cage
Crankset: LX 175mm
BB: ES-70
Cassette: Ultegra 12/25
Shifters/levers: 105 STI
Brakes: STX Canti front (crap, I know) and Tektro Mini V rear - both came with the frame and fork. Found some cool green Tektro cantis on eBay for $15 to match the funky orange/green Kelly frameset - not yet rec'd.
Peds: Time ATAC

I've been receiving conflicting reports as to the compatibility of the STI Road shifters and the MTB front derailleurs. The primary claim is that the road shifters pull too much (or too little?) cable per shift/click/index relative to the MTB derailleur/crankset and rings (22-44) they're working with.

Some say it will absolutely work fine, others say it will be nothing but a headache.

Please discuss.

Thanks in advance,

re: CX Drivetrain Claritywspokes
Aug 14, 2002 6:36 AM
I had a bike equipped with Shim STIs and MTB derailleurs and MTB crankset. I set it up, checked it over, and never looked back. I had no problem. I ran all LX with RSX STIs. I nibbed and tweaked the front derailleur (bend with pliars to suit) and I didn't have any prob. You should be fine one you set it up and test it. I have long since sold the bike and on my other crossers, a Bianchi Project bike whored up to be a kick ass cross and a Surly both run bar end shifters. enjoy!
Only problem I've had...Steve_O
Aug 14, 2002 7:14 AM
I too have a Knobby X. I started off with an XT front Derailleur with Ultegra levers on an XT crankset. Everything shifted fine but the lever arm of the front derailleur (where the cable is attached) would rub against the rear tire when I shifted into the big ring. I was running 700x30 Michelin Muds (which are the biggest 30c tires I've ever seen) so a slightly smaller tire would have probably cured the problem.

My solution was to switch to an Ultegra front derailleur. Everything else looks good to me!
Only problem I've had...atpjunkie
Aug 14, 2002 10:12 AM
was running D/A STI's and XTR Der. and Cranks. Worked great w/ no problems. Put the STI's on my roadie and replaced w/ D/A barends. Cheaper and more reliable. Have had no problems with the set up at all.
Could be...Steve_O
Aug 14, 2002 12:52 PM
My problem could be more a result of frame geometry or simply the fact that the tires were too fat (too close to the seat tube)...

Anyways... Anyone want to buy a brand new XT bottom pull derailleur?
Could be...atpjunkie
Aug 14, 2002 1:33 PM
30 shouldn't be too fat, I'm running 35's and 38's with no issues. Is it a top or bottom pull derailleur? Maybe it was wrong pull/swing combo.
But you know...wspokes
Aug 15, 2002 3:00 AM
every single manufacturer measures the tires different. One compapnies 30c is anothers 35. they all measure differently. I also looked real quick last evening, I am running ultegra bar ends with an XT rear derailleur and an old Campy front derailleur. RSX triple micro crankset with horrible chainline due to using whatever available spare BB I had lying still works flawless. Enjoy!
re: CX Drivetrain ClarityBAM
Aug 14, 2002 7:33 PM
The headache starts when you try to use a front road der and crank with rapidfire shifters. Does not pull quite enough, which is why Shimano has flat bar road shifters and a matching front der. Using STI`s with mtb ders. seems to work for many without problems.
Using LX rapidfire and Ultegra FD/Crankset. Works fine...TFerguson
Aug 15, 2002 5:26 AM
I beleive that "flatbar" is a relabelled Deore shifter.