mmcc73

I'm rehabbing a Raleigh Super Course Mk II, and I think I'm having a problem with the alignment of the rear derailleur. The derailleur seems to catch when pedaling (especially noticeable when pedaling backward) and it doesn't look like the chain is tracking well on the little gear in the cage.

See pics below - does it look out of whack? All the info I've seen on derailleur alignment is for bikes with built in hangers. does it work any differently when using an adapter claw?

wschruba

There are two things to check, in order: that the dropouts are parallel (use the "candlestick" tools), and that the claw is straight (unbolt the derailleur from the claw--see the thin but at the back). It can be bent, if need be, using an adjustable wrench. Sometimes you can use one of the old brake arm bending tools as a lever, but this depends heavily on how strong the derailleur claw is.

FBinNY 

The first step is to check the alignment with the bike's plane.

You can do a quick eyeball check using a broomstick o similar straight edge held vertically with the wheel. That makes the vertical plane obvious, and it helps to shift to a gear with the cage vertical . Then squat behind the bike and compare.

The same thing can be done front and back by working the horizontal axis.

As far as actually straightening it goes, use a big screwdriver, levering against the freewheel (not beautiful, but it works fine).

USAZorro

It's always difficult to tell from pictures, but it may be out slightly (looking at the spoke protector and the rd makes it look like the bottom of the derailleur is a couple mm closer to centerline than the top. Also note that the principles of correction are the same either with, or without the hanger.

That said, balky backpedaling may be due to spring tension.

mmcc73

When you say "spring tension" I assume you mean the spring that pulls the cage backward? Too much tension or not enough?

I'm not sure if I have the loop on the end of that spring engaged with the correct hook on the cage. I think I chose the one that would put less tension on the spring.

USAZorro

Unfortunately, I am a trial-and-error mechanic with some things, and I'm not familiar with that specific model of derailleur. I think you want the higher tension position, but I'm not certain. If the rear derailleur pulls forward to the point where the chain binds, something isn't right. It could also be due to the freewheel though.

CliffordK

Are you used to friction shifting? Being shifted slightly off-center will cause chain slack when back pedalling.

I've also noticed on my bikes that a little slack when back-pedalling often indicates that I've gotten myself cross-chained.

Prowler 

OP, If that was my bike, saw in real life what your first photo shows then, yes, I'd work on the alignment. I'd confirm/adjust the drop outs to ensure they were straight and lined up with each other - the Park 'candle stick' tools are great. Review Sheldon Brown's article on this. I'd do this on principle just cuz it's an old bike and life happens to old bikes (you should have seen how wacked the DOs were on my winter project!).

Then, yes, if I saw the RD cage hanging the way it looks in your picture, I'd remove the RD and check the hanger alignment. Do so either using my home made alignment tool or the Park tool (nice design there). I've had several RDs that were just not happy and "turned over a new leaf" with the hanger/claw aligned with the wheel. It does not take much mis-alignment to cause trouble. Well worth the effort. I approve being fussy here and trying for perfection. You'll learn that 'good enough' needs to be really good.

If you don't have the tools or cannot make them, then its worth having the LBS do it. Could cost $45 or so. Hint, CLEAN the bike first so you don't pay shop rate for them to clean it.

One bit of witchcraft to pass along. If you can find two identical thin strips of wood - dead straight, about 8" long by 1/4" and just thick enough to slide between the FW cogs and hold there.... then tuck one in between the largest cog and the next one, straight up and down. Clip the other stick to the wheel side of the RD cage. Align them to point straight up. The length of the sticks will visually amplify any vertical mis-alignment and show what needs bending. Woodworkers call these 'winding sticks'. May help with horizontal alignment too but I've not tried that.

jimmuller 

This may be obvious but have you cleaned the pulleys so they spin easily? A tight pulley would restrict the free flow of the chain in either direction. Though you may have a misaligned RD due to a bent DO or other factor, it wouldn't normally cause the chain to "catch" unless the chain were physically touching something that can't move. The chain itself is flexible enough to accommodate some misalignment.

mmcc73

Oh yes - the derailleur had a lovely bath in citrus degreaser followed by some fresh oil. She spins like a champ.

mmcc73

So I'm not imagining that the cage is pointing a bit toward the wheel. Whew.

Seeing a couple of suggestions for frame and derailleur alignment, I think I'll be taking the bike on a little trip to the LBS. I don't see myself doing this operation enough to justify buying (or fabricating) the proper tools. And, I don't want to experiment too much on this frame.

I certainly hope it is clean enough, having just stripped it down, cleaned everything, repacked the spinny bits, and put it back together again

qcpmsame 

I agree with @Prowler, and @USAZorro, you seem to have gotten the point too. Looking at the first picture in your IP, the bottom of the cage/pulley does seem to be closer. I'd use the advice given above by @FBinNY and Prowler to solve your problem.

Good thread topic, also. Learned a good method for aligning the RD, and a hanger including a claw if need be. Time to do some tool shopping for an alignment tool.

Bill

Salamandrine 

The picture shows that it is clearly out of whack. Needs to be straightened. Claws are straightened just like a built in hanger. Doing it by eye is typically not very accurate. I recommend a tool, homebrewed if need be.

Also check for stiff links in the chain.

USAZorro

When all is aligned, and before you ride, I suggest you generously grease the pulley wheels. Grease lasts far longer than oil, and it also serves to protect against road grit infiltrating the bearings.

The Golden Boy 

Is that a short cage Duopar?

If it is a Duopar- google Duopar and backpedal or backwards... Those derailleurs were susceptible to damage when turning backwards- but not like you're describing... I think.

I've removed my Duopars.

Road Fan

I've seen that duopar problem, but it is prevented by accurately feathering the rear derailleur and avoiding back-pedaling when you don't have to or are not sure you feathered it right.