Stumpy Fsr Cable Housing / Shifting Problems?????
I just built a new bike using a 2004 stumpjumper FSR frame and am having some problems.
The problem stems from the rear derailleur cable housing piece that is located at the bottom bracket shell. I had my mechanic build the bike and at first he cut this piece too short. The result was ghost shifting when the frame flexed on the trail. I had him lengthn the piece and now it is better, but I am still had problems as it was too long and caused lots of cable friction and poor shifting.
So I had him shorten it again but left enough to allow for suspension flex. I am still having problems though. Towards the end of my ride when the bike is all gritty, the cable sticks and shifting suffers or stops all together (the cable actually gets stuck and I cannot shift at all).
What can remedy this problem? I am using XTR drivetrain so it's not like I have cheap components. I don't think that I can shorten the loop any more.
Would teflon coated cables help?
I had my mechanic grease the cable that went through the housing. Is that maybe now causing grit to stick where it would not have otherwise?
what should I do?
Magic Line Finder
take your bike to a legit shop with qualified bike techs
I sense the FEAR... the fear of what you don't understand-
We want... a shrubbery!
What kind of conditions are you riding through?
Calvin : Ahhh, another bowl of Chocolate Frosted Sugar Bombs! The second bowl is always the best! The pleasure of my first bowl is diminished by the anticipation of future bowls and by the end of my third bowl, I usually feel sick.
Hobbes : Maybe you shouldn't use chocolate milk.
Calvin : I tried Cola, but the bubbles went up my nose.
I thought my mechanics were decent, but perhaps I should take it somewhere else. The best my mechanic from my shop recently left.
The condtitions here have been wet and the ground is sandy. Makes for sticky/gritty conditions.
I also found that after washing down my bike with a hose following my ride, the the bike now will basically not shift well at all---in either direction and will not shift all the way down into my small cog. It is basically not rideable. This has happened after all 3 times that I have ridden the bike. Each time I have had to take it back to the shop.
Originally Posted by bowler1
Matt, check out this thread, it has a good pic of the cable and how it should be run under the BB shell.
I also have an 04 Stumpy 100, and highly rec. flak jackets for your stumpy. They will work better and last a lot longer.
Full length cable housing on a SJ
Also agree with finding another mech. This is not rocket science, it should take that much effort to get it right.
Here's a few more pics I found
Here's a few more pics I found.
Bike to the Bone...
Is your LBS a Specialized dealer? Maybe it's a dumb question, but it may affect. I had a Stumpy FSR 2004, but I had trouble shifting my front der. . The mechainc where I went I think was pretty good, but he handled Cannondale and Giant. I took the bike to a Spec. dealer and he left the bike shifting wonderfully.
Just a thought.
The conditions you describe are the worst and a challenge to any system. The water carries the grit into your housing and gets trapped in the teflon coating and yech! This shows up in the section below the BB and the rear cable loop by the der for a double whammy.
My LBS also used a cable housing below the but used teh 4mm size with very close fitting plastic ends. The lead cap has a "snorkle" which passes through the front cable housing mount on the downtube. That "snorkel" is then covered with a sort of rubber sleeve in front of the housing mount. Teh sleeve is about 1.25 inches long with a farily tight fit and slips down over the "snorkle." My LBS called it a condom.
I hate to say this out loud for fear of bringing down the wrath of the cycling gods but this has worked pretty well. In fairness I don't ride in really crappy conditions much as I used to; it just sucks up riding time with cleaning, maintainance, misery, and repair. I also use my Bontrager as a "rainbike" which is much simpler to maintain.
My LBS has a couple of guys who have gone to full length cable housings affixed by zip ties. The loop near the BB becomes critical. So far it seems to be working well.
In the end the problem is really cruddy conditions finding the weak spot in a system. It is well to remember that some problems do not have solutions but that they must be managed as best one can. Perhaps mid-ride rinsing of the problem areas will make the rest of the ride better and full cleaning afterwards the norm. If you know how to remove the housings by putting the chain on the largest of the rear cogs and then taking all the tension off the cable by returning your shifter to the number one position, then sliding the housings out of the mounts and up the cable is easy. Rinsing and trailside cleaning is then possible and takes only a few minutes.
All of these solutions are better than blaming the mechanic.
Hey bowler 1, try this link;
The outer sheath of these cables are actually small, hollow aluminium cylinders. They should cut down a fair but on friction and stretch, but I am not so sure how you will route them around the bottom external curve of the bottom bracket shell.
I think these cables are meant for brakes, but I am sure there are versions for derailleurs (or just use the brake ones).