XTR derailleur spring tension issue?

[udi]

I've got a small problem with my m952 derailleur, i'll try to explain, but it's hard to.

I've just completely rebuilt it, cleaned every part, regreased everything, cleaned and repacked bearings, the lower knuckle spring is in the low-tension hole, and everything works smoothly.

The problem isn't a big one, just small and annoying

When i'm adjusting it, it doesn't like to shift into lower gears that much, so I have to turn the cable tension adjuster on the der. in a lot to get it to shift to 9, and then it struggles on the way back up because of the lower tension -- I CAN get it so that everything works and shifts fine, but im sure it could be crisper and firmer in shifting if the springs pulled it down towards gear 9 harder.

This is by far the most retarded thread i've made so I hope someone can make sense of it - basically i'm wondering, are der. springs known to go soft after some time, and can I buy good replacements or upgrades anywhere

note: high/low are set perfect, and yes it all works the same before and after I rebuilt it, just trying to get it absolutely perfect.

thanks in advance
udi

[lotec]

Ive also got this problem with my xtr and its bloody annoying :evil:

[Grover]

I've never had this problem as I've never kept a derailleur long enough but it just sounds like the spring is at the end of it's life. I'd say just go buy a new spring and put it in. They're pretty hard to find but some shops have them. If you're in Melbourne I recall Cycle Science in Mitcham having some XT ones which wouldn't be much different.

Cya, John.

[Cave Dweller]

Xt stuff in general won't fit in properly, the B tension system is slightly differant.

Udi, i had this problem with one of my old xtr m952's. It lost tenion at the hanger area so it would shift funny and not keep proper tension on the chain so it would skip. The propblem was the hole in the derailler that the b-tension spring sits in had ovalised. Nothing you can do about it but keep it for spare parts if thats the case. What i did was buy a cheap m952 long cage from the states (like $55US) and then swap over the cages with the busted one and you have a brand new m952 medium cage for cheap.

-Matt

[udi]

thanks cd

So you can't buy 952 spares.. that sucks.

Which spring is responsible for pulling the derailleur down to the last gear, it's the cage spring right (dunno what its called)? Or is the B-spring involved as well?

Can I replace the cage spring if I find one, and is there anything available? Can I take it out without any worries.. it looked hard so I left it in there..

My B/P spring holes aren't ovalised, but I did notice the last coil of the B-spring was bent a little bit which probably doesn't help.

The last problem I had (unrelated to the other stuff) - When I tighten the derailleur onto the hanger, it locks up and restricts the B-knuckle/spring... I've loctited and screwed it on without tightening it much to keep it working, but any thoughts why it locks up when I tighten?

Thanks again

[udi]

bumpity bump
few questions in above post that i still don't know the answers to..

thanks!!

[Cave Dweller]

So you can't buy 952 spares.. that sucks.


The only spares for xtr stuff that shimano australia keep is the btension set up. Phantom cycles have some.

thanks cd
Which spring is responsible for pulling the derailleur down to the last gear, it's the cage spring right (dunno what its called)? Or is the B-spring involved as well?


The amount of cable being pulled from the shifter determines what gear you are in. The spring around the hanger provides the tension. The spring in the cage just keeps the chain in tension.


Can I replace the cage spring if I find one, and is there anything available? Can I take it out without any worries.. it looked hard so I left it in there..


You probably won't be able to find one. You can take it out but it is a bit of a pain to reassemble. It is the same setup as the other spring.


The last problem I had (unrelated to the other stuff) - When I tighten the derailleur onto the hanger, it locks up and restricts the B-knuckle/spring... I've loctited and screwed it on without tightening it much to keep it working, but any thoughts why it locks up when I tighten?


Sounds like you didn't put it back together correctly. Might have missed a spacer putting it in. Did you reassemble it with parts from other non xtr deraillers? Like i said, it won't work if you have, it's different.

[udi]

thanks cd
Which spring is responsible for pulling the derailleur down to the last gear, it's the cage spring right (dunno what its called)? Or is the B-spring involved as well?


The amount of cable being pulled from the shifter determines what gear you are in. The spring around the hanger provides the tension. The spring in the cage just keeps the chain in tension.


No, the shifter pulling the cable pulls the derailleur up from gear 9 up to 1, but it is a spring, or springs, that pull the derailleur down back towards gear 9, all the shifter does when shifting down like that is "give" a set length of cable. I was just wondering which spring/springs pull it down

Anyway it works fine now, (I think I was just overtightening that B knuckle screw originally so its all good now). I still wouldnt mind firmer action pulling the derailleur down to gear 9 so thats why I wondered which spring does that duty.

If I knew which did it I could find a replacement :D

[Cyco]

uDi the spring you are referring to is the one inside the parallelogram.

On XTR there is a small (Phillips head?) screw near the cage pivot on the underside that has a high and low tension setting for this spring. To try and replace this spring it would require pressing and and reinstalling the parallelogram pivot pins.