Rear Derailleur at odd angle?

[toby123]

Hi,

some time ago, I had a new Shimano Acera rear derailleur (RD) fitted at a LBS, and the new arrangement sits at what seems to me to be a funny angle (pointing somewhat foreward). See below:



Almost every other bike I see has the RD pointing in this sort of direction:

http://beaconcycling.com/how-to/how-to-adjust-your-rear-derailleur-pg178.htm

This was the way my old one was. However, I have seen a few variations on other bikes.

Is mine OK, and does it affect the performance / speed of the bike at all?

 

[TheDoctor]

That's because you've got the chain on the big ring at the front and one of the bigger sprockets at the rear. The cage is being pulled forward because there isn't so much slack in the chain for it to take up. Perfectly normal, that's how they're supposed to work.
If you want to be sure, then try changing onto the largest sprocket at the back and at the front. If it goes, but only just, then the chain is the right length.
Obviously don't ride on the big-big combination!!

 

[toby123]

Many thanks. I will point out though that the chain is actually on one of the mid-sprockets not one of the big ones. I have also just found a picture of my bike taken a year ago before the work was done (unfortunately the picture is of the left-hand side of the bike so I can't verify the make of the old RD) and I can see that the RD is pointing downwards (the gear combo is the same). I just don't understand why it is now different.

 

[02GF74]

hmmm, I reckon LBS knackered the link and had to take another out - assumoing you replaced with identical rear mech.

what does the mech look like when chain is on largest chainring and smallest sprocket? I think then the two jockey wheels should be aligned vertically.

I have shimano leaflet describing how to work out correct length of chain but can't find it right now.

 

[02GF74]

see here: http://www.parktool.com/repair/readhowto.asp?id=26

 

[GrasB]

Carefully & slowly shift onto the large sprocket of the cassette, in an ideal world you should have the smallest amount of kink in the chain in that combination. It may be the new rear mech has much bigger jockey wheels which is taking up more chain

 

[toby123]

I really appreciate this. Looks like the chain might be too short. How could the LBS do this?

Even worse, now the front mech has stopped working so I can't shift betweeen the chainrings. Haven't had it that long. What can I do to fix it?

Help!

 

[Midnight]

Your lbs isn't Halfords is it? <snigger>

 

[PatrickPending]

I'd guess your chain was 2 to 4 links too short. Front derallieurs sieze up now and again esp this time of year (Ive never had problems with ultegra or dura ace tho) - Could be cables/ outers need changing or mech needs a good oiling. See if the cable goes slack and mech doesnt move (problem mech related) or cable stays tight (cable related)

Some lbs are rubbish!

 

[toby123]

see here: http://www.parktool.com/repair/readhowto.asp?id=26

This was very helpful. I have made a diagnosis of short chain and will be making a visit to the LBS tomorrow. I'll probably have to pay for a new chain to be fitted (assuming the current one can't be lengthened - can it be?). I wish I'd realised this at the time but as it's some months ago now I'll just have to take it as a lesson learned.

And the front mech has decided to start working again.

 

[02GF74]

This was very helpful. I have made a diagnosis of short chain and will be making a visit to the LBS tomorrow. I'll probably have to pay for a new chain to be fitted (assuming the current one can't be lengthened - can it be?). I wish I'd realised this at the time but as it's some months ago now I'll just have to take it as a lesson learned.

ofcourse it can. I may have a couple of spare link, shimano chains, 8 and 9 speed if you need.

modern chains have the pins swaged over so that once they are pushed out to split, they are a bugger to get back in without mandgling hte plate although it is possible to do this.

for that reason, shimano make a specail pin, about 99 p but damn expesnive for what it is - you would need two of those to rejoin the chain.

there are special split links - they have a slot so with a special tool or pincers - can be split and rejoined many times. (never throw those away but keep in you toolkit , handy if ever your chain snaps whilst out)

my theory, as I put in first reply, is LBS splitthe chain and could not rejoin with the chain. maybe manglking as link so took a link out.

you will be better off buying a chain splitter - Tesco used to do a pretty decent one in the value range but I haven't seen one for a while - if you are flush, then the shimano chain splitter is the business. maybe a tenner.

then you'll be able to fit all your own chains.

 

[GrasB]

Unless the chain is fairly new do not add extra links as when the existing links wear on the established chain you'll may well get weird gear jumping problems.

 

[betty swollocks]

If your chain's on the big ring at the front and the third or fourth in at the back, the derailleur looks about right to me.
The different combinations of front rings and rear sprockets require differing mounts of chain and one of the derailleur's jobs is to take up the slack, so that the chain is always taut. This means that the angle of the derailleur will change depending on the amount of slack it has to take up.
So long as the gear changes are slick, I shouldn't fret about the angle.