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Originally Posted by garysol1
(Post 5980265)
The Bike:
1985ish Benotto/Columbus SL tubing Campy SR deraileurs, 6 speed regina freewheel Friction shifters. Problem: When I put the hammer down the bike consistently down shifts, sometimes putting the chain between the cogs which makes for a very eye opening moment. What is going on here? I have checked all the mechanicals. Dérailleurs have no play in them and shift perfectly. The levers are nice and tight. The freewheel has no play. Am I running into frame flex? Any other idea's on things I can check? Assuming it is frame flex I guess there is not really much I can do or is there? Do a search for "ghost shift" or "phantom shift". 90% of the time it's related to lubrication in the derailleur cable at the BB guide and in the rear turnaround casing. 8% of the time it's a problem with the keyed friction washer in the shifter not being keyed so much anymore. 1% of the time it's a cracked frame. 1% of the time you're just too big a gorilla to be riding that flexy thing without index or retrofriction levers. These are scientific numbers. |
Originally Posted by melville
(Post 5982109)
90% of the time it's related to lubrication in the derailleur cable at the BB guide and in the rear turnaround casing.
Originally Posted by melville
(Post 5982109)
8% of the time it's a problem with the keyed friction washer in the shifter not being keyed so much anymore.
Originally Posted by melville
(Post 5982109)
1% of the time it's a cracked frame.
Originally Posted by melville
(Post 5982109)
1% of the time you're just too big a gorilla to be riding that flexy thing without index or retrofriction levers.
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Originally Posted by caloso
(Post 5980893)
In my experience, a bent DR hanger causes poor ****ing in some gears, not all. So you can get it to sit perfectly on the top gears, but it won't shift correctly all the way across the range.
[edit] Apparently, if you misspell "shifting" the censorbot will get you! |
Originally Posted by repechage
(Post 5982217)
"eyeballing" the hanger is not enough, beyond that, "crosschain" it, small ring/smallest cog, if it jumps, then chain/freewheel non compatible as said and or one is worn too much. If it does stay engaged in the sm/sm, then look at the other stuff memtioned. to test the middle cogs, a method is to lock in the gear, using the adjuster screws, no not ask the cable to do anything, if the problem comes back, your freewheel is now a fishing weight, spare cogs? wrong decade to look, unless you are especially lucky.
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how worn are the pulleys?
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Originally Posted by onetwentyeight
(Post 5982595)
how worn are the pulleys?
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Originally Posted by RK1963
(Post 5984938)
Make that cable housing 2 1/2 inches longer.
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Originally Posted by RK1963
(Post 5984938)
Make that cable housing 2 1/2 inches longer.
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Originally Posted by garysol1
(Post 5984947)
Are those metal housings still available? I really like the look of it.
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Originally Posted by RK1963
(Post 5987470)
I'm speculating that if your RD cable were longer, from chain stay stop to entry into the RD, your shifting problems may resolve.
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Originally Posted by garysol1
(Post 5987586)
I am going to lengthen the cable and use a longer housing at the deraileur. Hopefully that will help along with all the lubing I have done.
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Originally Posted by RK1963
(Post 5991640)
Let me know if that helps----once again, I believe it will
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Disassemble, clean, and re-assemble your dt shifters. I thought that mine were tight as can be but, as it turns out, the pieces were somehow not perfectly flush and were allowing some slippage. It's easy to do, free, and will help rule out that problem.
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My old Uniglide 6spd freewheel is real sensitive to rear wheel/axle alignment. Sometimes she'll skip (in the 2 lower cogs) when I horse down on'er with all my 210+ lbs, and I can almost guarantee that the axle has slipped forward on the drive side. Not much, maybe 1 mm if that, but enough to fool those wonderful Uniglide twisted teeth.
tcpasley |
Took the old girl out for a 40 mile ride yesterday and did not have a single issue....YOOHOO!!!!
I took the advice to make sure the cable was clean and lubed especially below the bottom bracket. I did that as well as clean the chain and freewheel and lube it up real good. Thanks for the help guys. |
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