sticky rear mech

2clepto

Guest
ive been attempting to set up this bike for a few days. the groupset came from another bike which was a little tatty. i degreased things and reoiled them. im not really into degrease baths but have tried it out on this rear mech because it was pretty bad, jammed up on the bolt that attaches it to the mech hanger and last week i found screw fix sell 5ltrs for £8.

the problem is the mech wont spring back enough to tighten the chain,

20150521_223555.jpg


if i ease it back a little i shows this,
20150521_223607.jpg


the top jockey wheel ends up being too high in the first shot. ive got the screw that pushes into the hanger all the way in, the shots blurry on the silver screw,

20150521_223631.jpg


and it looks like a fix could be a longer screw? or a replacement derailleur?

thanks mark
 

lpretro1

Guest
The chain is way too long
 
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2

2clepto

Guest
The chain is way too long
i did think thy same thing myself the chain was too long but i dont think so because when im in big big

20150521_231424.jpg


theres not much further the mech can travel. it is a brand new chain and ive removed 10 links.
 
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2

2clepto

Guest
The mech is seriously out of position, the top jockey wheel should be more in line with the axle. Something is not assembled right.
that is what im saying lol the mech wont pull back enough.
maybe i have the chain too tight? but then its too slack on small small.
im looking for a different mech on ebay. cheers.
 

Tojo

Über Member
that is what im saying lol the mech wont pull back enough.
maybe i have the chain too tight? but then its too slack on small small.
im looking for a different mech on ebay. cheers.

I've had this problem before on a friends bike, the spring in the housing at the pivot point is gummed up or corroded or even may be broken, the pivot point being where you attach the rear mech to the gear hanger......:thumbsup:. I'm just outside Newcastle, pm me I can probably sort it for you.
 
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Cubist

Still wavin'
Location
Ovver 'thill
I think the mech is mounted the wrong side of the stop on the dropout. The jockey is too far forward in all the pics, ie rotated anticlockwise by about a quarter of where it should be.
 

Tim Hall

Guest
Location
Crawley
I think the mech is mounted the wrong side of the stop on the dropout. The jockey is too far forward in all the pics, ie rotated anticlockwise by about a quarter of where it should be.
I'd agree that the position looks all to cock, but in the (blurry) end on photo it looks like it's in the right position wrt to stop. I don't think you'ld be able to see the B screw otherwise.

Another vote for the spring in the pivot being knackered like @Tojo says. Have a look at the Park Tools how-to here. Or take it round to @Tojo
 

Globalti

Legendary Member
Terrible pictures but I'd agree that the main pivot spring may be broken or adrift. Check also that the cage pivot isn't seized up.
 

e-rider

crappy member
Location
South West
ive been attempting to set up this bike for a few days. the groupset came from another bike which was a little tatty. i degreased things and reoiled them. im not really into degrease baths but have tried it out on this rear mech because it was pretty bad, jammed up on the bolt that attaches it to the mech hanger and last week i found screw fix sell 5ltrs for £8.

the problem is the mech wont spring back enough to tighten the chain,

View attachment 89442

if i ease it back a little i shows this,View attachment 89443

the top jockey wheel ends up being too high in the first shot. ive got the screw that pushes into the hanger all the way in, the shots blurry on the silver screw,

View attachment 89444

and it looks like a fix could be a longer screw? or a replacement derailleur?

thanks mark
I can answer this question quickly and easily but before I do, the chain is not too long!

SORA 3500 series mechs have a 'fault' in the bearing/seal around the bolt that fixes to the mech hanger. The mech is sprung and should be free to swing forwards and backwards, but SORA 3500 mechs seize up unbelievably quickly (within just a few months if used in wet/muddy conditions or you use a powerful hose on it). Other Shimano rear mechs are far more durable and this is generally not a common problem with other rear mechs, however it is a huge weakness of Sora 3500 rear mechs
A shimano 105 5700 rear mech will set you back £25 and should last trouble free for years - spend some money f you have it
 
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2

2clepto

Guest
I'd agree that the position looks all to cock, but in the (blurry) end on photo it looks like it's in the right position wrt to stop. I don't think you'ld be able to see the B screw otherwise.

Another vote for the spring in the pivot being knackered like @Tojo says. Have a look at the Park Tools how-to here. Or take it round to @Tojo
much appreciated thanks.
 

Tojo

Über Member
I can answer this question quickly and easily but before I do, the chain is not too long!

SORA 3500 series mechs have a 'fault' in the bearing/seal around the bolt that fixes to the mech hanger. The mech is sprung and should be free to swing forwards and backwards, but SORA 3500 mechs seize up unbelievably quickly (within just a few months if used in wet/muddy conditions or you use a powerful hose on it). Other Shimano rear mechs are far more durable and this is generally not a common problem with other rear mechs, however it is a huge weakness of Sora 3500 rear mechs
A shimano 105 5700 rear mech will set you back £25 and should last trouble free for years - spend some money f you have it

:cheers:for the info on sora mechs didn't know about the inherent problem as I wouldn't have spent all the time stripping the mech on my mates bike, to save him a few quid, as its his winter bike its going to be back to me with the same prob later this year...! I would just have done him a deal on a upgrade rear mech and saved my time......:cry:
 
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2

2clepto

Guest
Update.

Bought a new mech (sora) and the bike works great now. tried a few things with the old mech but it wasnt having it. thanks to everyone for the help much appreciated.
 
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