eyemkeith

Hi all.
I've never attempted this before, so i'm going to say right off that I DO NOT know what I'm doing. All my knowledge has come from YouTube. For this, I apologize in advance.

I have changed the cables on my brakes and successfully installed new v-brakes to replace my cantilevers. Buoyed by this, I thought I'd change my derailer cables as well. The front went swimmingly. But the rear is being stubborn.

I have an old shimano 400 LX derailer and a 7-speed cassette. Simple enough. I changed the cable and housing and now I cannot get it to go through all the gears, no matter what I try. Mind you, I did nothing other than the cable.
I followed all the directions in the Park tutorial and several others: Turned in the barrel adjuster all the way, then two turns back. set the chain on the smallest sprocket, an my shifter to the highest gear, took the slack outta the cable, ran it through some gears and back, re-adjusted and took more slack out of the cable. The whole bit.

I cannot get the chain to the smallest sprocket without backing in the adjuster AND I cannot get the chain to the largest sprocket without erasing that adjustment and then some by backing out the adjuster a ton. It's kinda making me nuts. For whatever stupid reason, I thought this was going to be easy, since all I was doing was changing the cable. Also, all those damn tutorials showed guys with irritating accents making an o-so-simple cable swap. Liars!

Any and all suggestions are greatly appreciated.

I'm new to this bike mechanic stuff, but I'm determined to do my own basic maintenance, as I haven't found a shop I trust and the expense is just silly.

fietsbob

! #1 ) I use the shop tool to check the derailleur hanger is not bent out of alignment
If you go to your LBS its a cheap service they offer, that alignment check//
buying the $200+ tool may be in your budget to do this check, for decades..

Cable pulls the RD between 2 stroke limit screws, with no cable attached the H limit screw will stop it over the outer most cog,

the L one will stop it under the largest, low gear cog..

Need videos? I'm sure there are many to find, searching the topic..




...

eyemkeith

Thanks, man. But the derailer I'm sure is not the problem. It was working fine before, meaning yesterday, shifting happily between all gears. I stepped in because I had a dire need for my cable housing to be a different color and thought this would be a good opportunity to learn how to change my own cables, a decision I'm questioning now.

Oneder

I just did the same and it went perfectly. It may not have been working 100% already and you just didn't notice. Start by setting both the limit screws so they do not limit anything. Then set the bottom. Then put it on the bottom and manually shift and pedal with hands while it's on a stand and adjust the adjuster if it's not going up enough per click to make it up to the gear. Now set the top while you are on the top gear, keep going in til it starts to interfere with the chain, then back it off.

Digger Goreman

If I understand correctly, you are just using the barrel adjuster? Forgive if I just repeat stuff, but here goes:
(If the cables are all seated and capped correctly), shift into large front, small rear. Loosen the cable at the rear derailleur. Lightly force the derailleur arm inward while rotating the pedals till you reach 6th gear. Hold that position and tighten the "H" adjustment screw till it just stops. Let go of the derailleur. While rotating the pedals, back out the "H" screw till you just reach 7th gear; back a quarter turn more and this establishes a fool-proof chain limit. Pull the derailleur cable lightly tight and secure with the derailleur nut.

Shift into smallest front and rear second gear. Tighten the "L" screw till it just stops. While rotating the pedals, back out the "L" screw till you get 1st gear. Then back a quarter turn more and the upper chain limit should be golden.

Go through the shifts and use the Barrel Adjuster as necessary.

Hope that helps....

woodcraft

Make sure that the cable housing pieces are all set in their stops, and that cut ends of the housing were opened up with an awl
so the cable runs freely.

Hold onto the cable end and count the shifter clicks to check that the shifter is in the highest gear position.

Make sure that the cable is clamped the right way on the pinch bolt- if it goes on the wrong side of the bolt it won't work right.

trailangel

We don't know WTF you did either.
New Cable housing? 5mm housing or 4mm housing.
Did you route the new cable correctly on the pinch bolt of the rear derailleur? ??
Rear Derailleur top jockey wheel needs to be just outside of the smallest cog before attaching the cable.......read the instructions. I say again... read the instructions.

eyemkeith

Wow, dude. No reason to be so harsh. I think I made it pretty clear I did not know what I was doing.

eyemkeith

I turns out on this original 1992 equipment, the "H" screw is frozen in time, maybe rocking out to some sweet Nirvana bootlegs, I don't know. I cannot get it to budge in either direction, either with a screwdriver or a set of pliers. I'm thinking about springing for a new derailer. They're not hugely expensive.

woodcraft

But it apparently worked fine before,

and if it will go into H gear with the cable slack, then the limit screw is not the issue.

eyemkeith

That's what I was thinking, yah.

Oneder

You can get a higher gear derailleur if you like and that will let you upgrade to bigger cassette later but you may need a new chain. In fact may as well get one anyway.

blamester

Start again. If it was working fine before it will again.
Don't go adjusting limit screws for now.
Loosen off the pinch bolt let it shift in to the smallest and make sure the shifter is also in the small position.
Then pull the cable tight and tighten the pinch bolt.
You may need to adjust the barrel adjuster.
If the cable is not seated correctly it will be apparent when you click the shifter.

Retro Grouch 

Here's a step that Park and U-tube might have overlooked:

Before attaching your shift cable to the derailleur, make sure that your SHIFTER is in the hardest gear position. Don't ask how I know.

Homebrew01

Do you have "Indexed" gearing, or "Friction" gearing ?

Indexed: The shifter has a "Click" for each gear in the rear, so you just shift as many "clicks" as you want.

Friction: No Clicks, you find each gear by feel & practice.

andrewclaus

My first guess has been mentioned once--be sure the cable is attached on the correct side of the RD pinch bolt.

Also mentioned, worth repeating--with new housings and end caps, it may take some force for the caps to get fully seated. And housing lengths and routing are important.

There's a slight chance something else broke or bent during your work.

frankenmike 

First things first: completely disconnect the cable from the derailer. Turn the pedals. It should shift to the highest gear. Push the derailer inwards with your hand while pedaling. It should be able to reach the lowest gear. If so, the limits are fine.

steve sumner

for indexed shifting the cable housing needs to be compressionless
it has little steel wires inside that run the length of the housing.
if the setup worked yesterday I suspect you bought generic housing
instead of indexed shifting specfic

eyemkeith

Hi all.

I didn't want to just leave this hanging. Thanks to your helpful advice, I got the derailer to work properly. I'm very excited to have vanquished this beast, with your help.

I wish I could tell you what the original problem was, but that still eludes me. I took a day away from it, and just rode with the missing gear instead. When my head was clear, I took Frankenmike's advice and unhooked the cable from the derailer and moved the mechanism with my hand. It worked just fine through all the gears, eliminating the limit screws from the equation. So I just stepped back, unrolled the bar tape and just started all over again. I unhooked everything and pretended nothing had ever happened, started from scratch. The stars aligned and it worked perfectly the first time. It took, like, eight seconds.

I must've either been trying to get the cable too tight, or didn't have a housing seated properly or something. I dunno. But it works and this is a very good thing indeed.

Thanks especially to Frankenmike for that bit of advice, which I'll use from here on out, and thanks to everyone who offered constructive advice for a newbie when you didn't have to. It proves again that bike people are the best people.

Ride on.

Keith.

Homebrew01

davmcman

Another newbie with similar issue. Front housing cable was split - went to bike shop Saturday to have them replace and first available appointment is JULY 20th. So I asked if I could just buy the parts..... Guy grabs a box a cable housing and measures it against the bike and cuts a couple of pieces, gives me some caps and a cable and off I go..... I had done some "adjustments" before I realized cable was shot originally so I knew it would require some effort once I replaced. I installed cable/housing etc and it shifts! Its 7 speed derailleur and it can go from the smallest cog to the 3rd from the largest but no further. I watched 382 u tube videos and verified my high limit is set properly, low limit is pretty much backed out. If I adjust barrel adjuster out I can get it to go up one more cog, but then I cant get back to the smallest. Its like there is a not enough range.
I noticed on a comment above andrewclaus mentioned cable housing lengths and routing matter? I just checked and the shop gave me two identical lengths of housing where the original housing on the rear was about 2 inches shorter. Could this be causing my problem?

davmcman

After fighting this 4 hours over the weekend and posting this, I read another thread about "not having enough clicks" in the shifter. I tried what was suggested there and tested it with cable disconnected and sure enough only had 3 clicks. Tried to take it apart but couldn't figure out how without trashing it so I went back to the old standby..... WD40 into the shifter. 6 clicks now. Put new cables on and everything working after a few adjustments.

Moe Zhoost

Wow. Two success stories in one thread. This is excellent.