Bicycle Mechanics - Can one take apart a standard XT front Der?
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I've noticed that my front der. shift like crap in these cold weather. Granted this is a vintage '95 Deore XT bottom pull der which has seen 3 years of year round commuting and the rest as my first mountain bike. I've noticed the der doesn't want to shift from the middle ring to the granny when it's cold because the pivots are either frozen or so full of crap, I can't get at it. Usually I'll take some silicone spray or other kind of lube and spray the pivots and that will usually work for a bit, but I'm wondering if I can take the thing apart and really lube it from the inside or is it basically, throw it out and get a new one?
01-19-04, 05:59 PM
Look at rear wheel facing side of the der. If you can take it apart(at all) one or two of the pivot points will have socket heads and you can loosen them and clean them to free up the der. Personally I would not unscrew them all the way, they can be tough to get back in(under spring pressure).Just loosen them and clean and lube what you can reach.
If you can't take it apart, remove it and put it in the parts washer and soak the heck out of it or (if no parts washer) spray the heck out of it with carb cleaner and then lube it up with triflow and action it abunch with your fingers to work in the lube.
I'll second the good Reverend's recomendation. A good soaking in solvent and some scrubbing with an old toothbrush (don't use the wifes) will restore it to like new.
01-21-04, 03:13 PM
When mine got to the point that it was not shifting properly, the pivots were worn out. It was also rattling around like crazy. You could move the cage all over the place with your hand. If yours is like this, I would replace it. If it is tight, do as the Rev says.
01-21-04, 09:43 PM
One more thing, it's not the shifter that is causing the slow shifting by chance. I see this in older shifters in the winter. The grease gets so thick the things barely work. You can check by shifting using the cable only to shift it.
Same solution, flush it and relube it.
I checked the cage, it's solid, it's not loose or anything. And I know it's the derailleur itself because when it's not shifting properly, the cable is slack and there is not crimp at the bottom bracket. So either the pivots are grimmed/shot or the internal spring is old.
Another thing, looking at the ends on the pivots, out of the 4 pivots I see on them, only 1 of them seems to have a cap that I can remove with a flat screwdrive. It's the pivot that is closer to the bike on the inner cage and lower one. The rest seem to just either be a bolt that isn't threaded either that or there is something special needed to take those off unless they need to be pryed off.
I will take it off this weekend and try to soak it the best I can. Right now my shifting method when using the granny gear (The only time I ever use the granny gear on my commutes is when I'm biking through 4 inches of snow on my commute.) is basically shifting down, unclipping my right foot and kicking the derailleur cage!
01-22-04, 09:29 AM
I'm guessing it is more gunked than worn.
Well, since I was off the bike last week, I decided to soak my front der from Monday to Sunday. Looking around my basement, I was wondering what to soak it in, somebody mentioned kerosene to me because of the chemical properties but didn't have any. I thought of motor oil since that will hopefully coat the pivots and bushings. So I had it soaking in motor oil from monday to yesterday morning. Yesterday afternoon, I cleaned it up and put it back on the bike and now it's a lot nicer, I can actually shift now in the front der. Of course, now the snow will melt and I wont have to use the granny gear again but that's another story. :)
02-02-04, 09:09 AM
You should still find a degreasing solvent to soak it in at some point, since you want to get all the dirt and gunk out. The oils has merely coated what is already there, and the effects will probably disappear quickly, especially if you get any water or mud in the mech. again.
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