shimano XTR rear derailleur loose?

Discuss light weight issues concerning mountain bikes & parts.

Moderator: Moderator Team

Post Reply
User avatar
devinci
Posts: 3039
Joined: Sat Jan 03, 2009 9:43 pm
Location: Canada

by devinci

My shimano XTR shadow plus cluth rear derailleur has a little loose when I remove the chain.

I realized that today while installing a new chain, the derailleur was a bit loose, it appears like it comes from the spring's attachement. Bolts are all tightened, the loose is only apparent when the chain is removed and the derailleur has no tension in it.

Anybody else noticed this?

TheKaiser
Posts: 469
Joined: Thu Sep 05, 2013 3:29 pm

by TheKaiser

devinci,

Sorry that I don't have any info for you right off the bat, but could you perhaps offer some more detail on this play that you feel? I might just be thick headed, but I can't quite visualize which direction the play is in from your description.

When you mention the spring, are you talking the parallelogram spring, or the spring the tensions the lower cage with jockey wheels?

Is the play for/aft, side to side/ etc?

If it's easier, could you perhaps draw some arrows on an photo to illustrate it?

If it is in the parallelogram spring, does it only exist when shifted to the smallest cog position?

by Weenie


User avatar
devinci
Posts: 3039
Joined: Sat Jan 03, 2009 9:43 pm
Location: Canada

by devinci

It is the parallelogram spring and only happened when I removed the chain. On the smallest cog with a chain on it doesnt seem to move. I will get some pics

User avatar
jekyll man
Posts: 1331
Joined: Wed Apr 25, 2007 10:23 am
Location: Pack filler

by jekyll man

I presume the shadow plus is the same as the xt shadow version, but I've had the top bolt (not the mounting bolt) back itself undone within a few rides on a number of bikes. might be worth checking??
Official cafe stop tester

User avatar
devinci
Posts: 3039
Joined: Sat Jan 03, 2009 9:43 pm
Location: Canada

by devinci

all bolts seem good...

The spring attachement point seems to be where the loose is. Only when the chain is removed though

TheKaiser
Posts: 469
Joined: Thu Sep 05, 2013 3:29 pm

by TheKaiser

I don't think you have explicitly stated this, but I am assuming you are noticing this while in the small cog position, correct?

Out of curiosity, with the chain off, does simply shifting up to the next cog position alleviate the play?

If so, when you feel this play in the spring attachment point, does there appear to be tension on the spring or is it slack?

If it is small cog specific, I am guessing that either your parallelogram spring is too long due to stretch/manufacturing error, or your dropout/hanger/hub geometry may be out of spec just enough to place the derailleur inboard enough, so that you are operating at the very edge of its effective range of motion, which leads to the spring being detensioned when in the small cog position. Obviously, it has been shifting OK, so unless you are a total perfectionist there is probably no reason to do anything about it, but it would be interesting to compare your derailleur to a brand new one to check the spring's free length, or put your derailleur on a different bike/wheel combo to see if existing limit screw settings place the pulley farther outboard.

You could also try building up the attachment points of the spring or something like that to increase its tension...M950 XTR had a cam adjustment for parallelogram spring tension so you could choose between more light action or positive shifting, but I don't think newer versions feature that. You also used to be able to get aftermarket higher tension springs, but I haven't seen those in a while either.

User avatar
devinci
Posts: 3039
Joined: Sat Jan 03, 2009 9:43 pm
Location: Canada

by devinci

Thanks for your reply

It is all good when on the smallest cog and small ring. When feeling the play, the spring seems totally slack, no tension.

Maybe this is why I sometimes hear a weird grinding noise when going from the 34T to to the 36T...?

TheKaiser
Posts: 469
Joined: Thu Sep 05, 2013 3:29 pm

by TheKaiser

Weird! I am having trouble visualizing what you describe, unless you are running a low normal (Rapid-rise) derailleur, which I don't think they ever made in a Shadow+ version. Is my assumption that you are running high-normal (parallelogram spring pulls der to smallest cog) correct?

It seems really strange that "It is all good when on the smallest cog..." which is when the spring should have the least tension.

The weird grinding noise from the 34-36 could also be a result of insufficient "B" pivot tension which is causing the top pulley to foul on the largest cog when shifting. Chain length can play a role here as well.

afalts
Posts: 157
Joined: Thu Mar 08, 2012 3:20 pm

by afalts

Do you mean that it can 'swing' slightly backwards and forwards when there is no chain on? That's normal if that's the case.

Agree with TheKaiser, the grinding going into the biggest gear is likely not enough B-tension, try turning it in only one half to one full turn if it's only happening once in a while.

by Weenie


TheRookie
Posts: 910
Joined: Wed Jan 18, 2012 4:23 pm
Location: Midlands, United Kingdom

by TheRookie

TheKaiser wrote:unless you are running a low normal (Rapid-rise) derailleur, which I don't think they ever made in a Shadow+ version. Is my assumption that you are running high-normal (parallelogram spring pulls der to smallest cog) correct?

There is no 10 speed rapid rise (more is the pity), so any shadow plus (10 speed only - until 11 comes along from Shimano) has to be high normal, yes.
Impoverished weight weenie wanna-be!
Budget 26" HT build viewtopic.php?f=10&t=110956

Post Reply
  • Similar Topics
    Replies
    Views
    Last post