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Help me shift...(4 posts)

Help me shift...Farmpunker
Apr 13, 2003 9:08 AM
Howdy,
I've almost got my Shaman built. My mechanic has run into trouble with shifting. I'm using a Race Face Next 46-34-whatever, standard. Ideally, I'd like to go with a double setup and drop the small ring. The mechanic said he'd leave the granny on to keep the chain from falling off and wedging betwixt my frame and the crank, or piling up on the granny ring bolt area and jamming up. Whatever. I wanted a double for fast shifting performance and I'm likely not going to need the granny since I don't plan on trail riding this bike much at all.
The mechanic hasn't had much experience with cross setups, so he's a little confused by the mountain crank on the road bike. He put in a mountain bottom bracket. The Ultegra triple shifter I had isn't working properly - mainly because it's screwed (adjustments aren't working properly). We decided to try a 105 braze on double. But I don't think this will work with a moutain bb. Am I going to have to use a mountain front D? Is anyone using a mountain front D braze on for shifting a double?
Anyone?
re: Help me shift...The Walrus
Apr 13, 2003 12:46 PM
Never had any problem with the LX derailleurs on my Wazoos or Axises (Axes?); none of the mechs are braze-ons, but I don't see that that should make a difference. ...and for the record, most of these bikes have Race Face (LP) cranks, and are double chainring setups. Haven't lost a chain yet. I'm not sure what you mean by a "mountain bottom bracket", unless you're referring to one with a long spindle to accomodate a triple. I think the one time I checked, the spindle length on the Axis was 110, and that was good enough to allow a granny; I use barcons to shift in this case, though, since 9sp STI is lousy with a triple, IMHO.
re: Help me shift...SenorPedro
Apr 13, 2003 12:48 PM
Well, there are all kind of potential problems here with this setup. First, it is good that you have the mountain BB, the triple requires a different Q factor, but you do not need the granny ring on there. If you are worried about chain drop then get a 3rd eye watcher.

The potential problems with the shifting setup are that road and mountain shifters have a different cable aspect ratio. They basically pull different amounts, so unless you have barcons for friction shifting, then you will run into some trouble there. That can be worked around, but delicately. Another issue may be that you are using a relatively short big ring, the braze-on derailluer may not be able to be lowered significantly enough to make good clean shifts. I don't know how your frame was designed however, so that may not be the case.

I would suggest that you forget about gears up front and make it a single ring. I don't know if you can find large chainring guards for 110 BCD, but you can just put a 3rd eye on the inside and call it good. Many people opt for this setup and use a 42 or 44 tooth ring, which, depending upon the cluster you have in the back will result in really only losing 1 or 2 gear ratios. Check cyclocrossworld.com for more info. Good Luck.
re: Help me shift...atpjunkie
Apr 14, 2003 12:19 PM
have run XTR front der. with MTB cranks and road shifters with no problem at all. I switched to BarCons for durability and now have less trouble.