sram red rear derailleur cage motion question

Discuss light weight issues concerning road bikes & parts.
djay001
Posts: 89
Joined: Thu Dec 22, 2011 3:59 pm

by djay001

Hi,

Hi just get a used sram red rear derailleur and checking it, i saw somethings strange on the cage motion.

Here is a video of this motion that i have putted on youtube.

http://www.youtube.com/watch?v=lhUfvDeIcQc
I'm sorry the quality is not really good, and sorry for the audio, my girlfriends was listening to some tv show.

So, bassicaly, the cage move to about 2mm from the derailleur body.
Is this normal? I also got a sram rival derailleur and this one don't do that.

Can i ajust this?

Thanks for your comment.

by Weenie


User avatar
theremery
Posts: 2673
Joined: Sun Jun 12, 2005 10:56 am
Location: New Zealand

by theremery

No...it's not supposed to do that. There is a tiny retainer screw that holds that whole part into the body. Note that yours is almost starting to pop the cage off. This is normally prevented by that screw sitting in the back of a protruding Ti axle inside the body. I suspect that this one has worn through the screw or bent the axel so that it isn't holding very well any more. Remove the small silver screw while someone holds the mechanism "unloaded". Once the screw is pulled out, you can let the cage gently unwind (carefully) then remove it for inspection. Straighten the axle if it is bent. Check the top where the axle engages is not damaged as it should jam if the axel is bent ....most likely, the axle is WORN. You can attempt a partial fix by going to a bigger gauge screw, or simply rotating the screw around so that a less worn segment of the screw is in contact with the axle (so it sits on an unworn part). Other possibility that comes to mind is that the Ti axle has come loose.
Either way.....it's internal inspection time. If that cage fails while you are riding, you could be talking Rear mech, frame, rear wheel plus crash damage....so get onto it :)
Updated: Racing again! Thought this was unlikely! Eventually, I may even have a decent race!
Edit: 2015: darn near won the best South Island series (got second in age
-group)..woo hoo Racy Theremery is back!!

djay001
Posts: 89
Joined: Thu Dec 22, 2011 3:59 pm

by djay001

Thanks a lot for your answer,

so i have unscrewed the little screw, and here is what a have discovered.
The top of the axle is worm, and the screw too.

Is it possible to twist the axle? because basically half of the top of the axle is worn, so if i can turn it by 1/2 turn, it will be ok.
Someone knows how to unscrew the axle?

I also got a sram rival derailleur so if it's not working maybe i can take the axle and the screw of the rival.

Also, is it possible to buy these part separatly?
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Last edited by djay001 on Wed Jun 26, 2013 2:58 am, edited 1 time in total.

Zigmeister
Posts: 921
Joined: Mon Jan 24, 2011 8:09 pm

by Zigmeister

Good post. This part is meant to wear and need replacing over time.

djay001
Posts: 89
Joined: Thu Dec 22, 2011 3:59 pm

by djay001

Zigmeister wrote:Good post. This part is meant to wear and need replacing over time.



ok but someone know where can i find it? and how can i unscrew this axle?

tuba
Posts: 106
Joined: Thu Aug 23, 2007 4:59 pm
Location: colorado

by tuba

i had the same problem but a little more wear
i got close to 20,000 miles so i was not to disappointed
i just bought a new derailleur

did the seller tell you how many miles were on the derailleur?
i would ask for a refund


the wear goes a full 180° around the pin
Image

jordo99
Posts: 106
Joined: Mon Apr 09, 2012 10:48 pm

by jordo99

I'd contact SRAM right away and see if they'll replace it or ship out a new axel...I've heard stories of SRAM going well past normal levels of customer service.

If SRAM won't help you out (which I honestly wouldn't blame them) I'd get a refund from the seller.

djay001
Posts: 89
Joined: Thu Dec 22, 2011 3:59 pm

by djay001

thanks for the reply,

and also this is nice to see that my derailleur is not the only one with this type of wear.


For the refund maybe i will check for it, but if this is possible to change the axle, i'll prefer this options.
I got this derailleur from eBay for 50$+shipping, in the auction they said this:
•It's seen a good share of use
•Both jockey wheels are cracked
•It's dirty, but will do work!

I was ok with the cracked jockey Wheel, i may just change these for new force/rival wheels. They really said that the derailleur have seen a lot of use, maybe i can talk about the *but will do work*



Also i see a lot of tunned sram red rear derailleur with the carbon cage changed for other lighter cage, so they surely need to put the axle on these new cage. I just need to know how they unscrew this little axle.

I will ask the question on the sram red derailleur tunning subject also.

Stockie
Posts: 350
Joined: Mon Aug 20, 2007 7:24 pm

by Stockie

after seeing this i get some questions about the cages once offered by Carbonschmiede. I thought that on this cage the axle was made of aluminium to keep the weight down. But this would make the axle diseappear after 100 miles...
I Will make the leap

User avatar
tommasini
Posts: 1296
Joined: Sun Nov 02, 2003 6:48 am
Location: Central USA
Contact:

by tommasini

djay001 wrote:Thanks a lot for your answer,

so i have unscrewed the little screw, and here is what a have discovered.
The top of the axle is worm, and the screw too.

Is it possible to twist the axle? because basically half of the top of the axle is worn, so if i can turn it by 1/2 turn, it will be ok.
Someone knows how to unscrew the axle?

I also got a sram rival derailleur so if it's not working maybe i can take the axle and the screw of the rival.

Also, is it possible to buy these part separatly?
Image
Image
Image
Image


Doesn't all what we see here seem fundamentally wrong - a "grub" screw (as I'll call it - maybe a better name) that is run in at 90 degrees to rub against a concave surface to keep things in check. How about instead using tight tolerances and a design on such a precision "tool" that allows it to be bolted up tight at the factory and no wear/tear like this (ala Shimano and Campy). This looks like voodoo weight loss (via the design) in exchange for shaving a few grams to brag about on a spec sheet or a few dollars saved of manufacturing costs - not my cup of tea.......this seems like "walmart" design.......get what you pay for. I'm a WW but not a budget weeny........

http://www.youtube.com/watch?v=lgg-X3lVrPs

http://www.youtube.com/watch?v=a6QoVYq7BYA

http://forums.roadbikereview.com/compon ... 44619.html

NoahK
Posts: 3
Joined: Tue Feb 27, 2018 2:52 am

by NoahK

theremery wrote:
Sun Jun 23, 2013 6:33 am
No...it's not supposed to do that. There is a tiny retainer screw that holds that whole part into the body. Note that yours is almost starting to pop the cage off. This is normally prevented by that screw sitting in the back of a protruding Ti axle inside the body. I suspect that this one has worn through the screw or bent the axel so that it isn't holding very well any more. Remove the small silver screw while someone holds the mechanism "unloaded". Once the screw is pulled out, you can let the cage gently unwind (carefully) then remove it for inspection. Straighten the axle if it is bent. Check the top where the axle engages is not damaged as it should jam if the axel is bent ....most likely, the axle is WORN. You can attempt a partial fix by going to a bigger gauge screw, or simply rotating the screw around so that a less worn segment of the screw is in contact with the axle (so it sits on an unworn part). Other possibility that comes to mind is that the Ti axle has come loose.
Either way.....it's internal inspection time. If that cage fails while you are riding, you could be talking Rear mech, frame, rear wheel plus crash damage....so get onto it :)
Hello everyone. I hope someone can still help me with this topic. I recently found out that this is my exact problem I'm having with a Sram Force derailleur. The derailleur cage almost seems "loose" and wants to bend towards the back wheel when the chain has tension on it. But when I tried to undo the little silver screw that is above mentioned, I couldn't. I tried WD-40, lots of pressure on the screw driver, and nothing :( .I don't know what to do at this point as the screw head is nearly stripped. The screw will turn in (tighter) with ease, but is super hard to turn out a few half turns until is ab-so-lute-ly will not turn any further. Any help would be appreciated. Thanks and keep on pedaling!

The first video listed by tommasini describes my situation, except the derailleur cage is already pulled towards the wheel. The cage is also turned outward, and the jockey wheels are not parallel to the cogs. For ease of explaining, the front of the jockey wheels are more outboard than the back of the jockey wheels, if that makes any sense.

alcatraz
Posts: 727
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Could you take a picture?

For screws where the head is nearly stripped you could try some heat + soak around the threads with some oil and let seep in.

If it won't come out it's time to use a small dremel cutting wheel and make a groove through the middle and just unscrew it with a straight bladed screwdriver.

/a

NoahK
Posts: 3
Joined: Tue Feb 27, 2018 2:52 am

by NoahK

Kinda hard to tell form the pictures but the cage does bend AND is turned towards the rear wheel.


I will try the warm oil and soak tomorrow, I had a nasty squeak in my drivetrian that wuld drive the Pope nuts! Luckily I got that fixed and I will be on the derailleur tomorrow. I am tired of constnatly working on my damn bike! #dontbuyused
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alcatraz
Posts: 727
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

You might have a bent derailleur hanger. If it were my bike I'd bend it to suit the natural shape of the derailleur, even if the derailleur is a bit worn.

If the derailleur has a lot of play in the linkage/cage then it will never be perfect. (I'd replace the derailleur or get an aftermarket cage)

I'm not a professional mechanic so I can't speak to the safety of the procedure I'm going to suggest next. But here goes...

I know my red derailleur has some wear but I adjust my derailleur hanger to suit the wear.

I learned that it's not simply about having a perfectly vertical cage (although it helps). What gave me the best results is to focus almost completely on the upper pulley. This pulley needs to be parallel with the cassette in both planes. Also check the pulley for play. There shouldn't be too much or shifting will be sloppy.

So I bend the hanger vertically (in or out from the wheel) using an adjustable wrench with the derailleur off the hanger (but still around the chain). I make sure to put the derailleur back every time I check for straightness. Always look at the upper pulley and make sure you look at a high chain tension gear and a low tension gear to find a middle point. (A derailleur with some wear will produce slightly different angles at different tensions)

Then I look with the bike flipped stright from below and see if the upper pulley is horisontally parallel with the cassette. If not I bend the hanger until it is. I recheck the vertical angle before I'm satisfied.

I don't pay too much attention to the lower pulley. Your limit screws will need to be reset when you make larger changes to the hanger angle. Use your fingers and do the push test and see if you can get the derailleur to touch the spokes of the wheel. You shouldn't be able to. Set limit screws appropriately with a safety margin.

First time I did this I thought I got it right but every time I do it I find I learn to hit the right angles better and better.

/a

NoahK
Posts: 3
Joined: Tue Feb 27, 2018 2:52 am

by NoahK

Ok thank you very much. I totally see what you mean by saying that the cage angle can be different depending on the chain tension. I am very afraid to bend the cage but I will try that if I still can't get the screw out. I also cleaned and tightened to pulley wheels and that seemed to make for a bit better/crispier shifting. I think my jockey wheels were a little loose, but that won't solve my problem. We'll see what I get out of this and if nothing else, I will just have to live with a wonky derailluer lol... :lol:

by Weenie


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