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2012-08-22 5:22 PM

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McAllen
Subject: Frustrated...

I've been trying to adjust my rear derailleur for a few hours now. I switched out my 11x32 cassette for a 11x23 (wanted 12x25 but the 11x23 was sold cheap)

anyways, I figured since I switched the cassette I would need to reset the rear derailleur. When I'm on the short ring on the front and the large cog on the back, my pulley is hitting my spokes HARD. Not enough to stop it but its bad. I've tried adjusting my lower limit, but its maxxed out and won't tighten any further. I took a look and my pulley is slightly bent in towards my spokes, I'm not sure whats wrong -.- when I'm on the big chainring its fine. It hits slightly but is adjustable enough so they won't mash.


I don't want to take it in to the LBS because they'll charge 15 to look at it, 10 to tell me I need a new derailleur and 80 for a new derailleur.

What could be wrong? can I try to bend the pulley-arm thing back out so its parallel to the chain? My derailleur hangar isn't bent I've checked that.



2012-08-22 5:50 PM
in reply to: #4375758

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Elite
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Subject: RE: Frustrated...

I think you do need to take this to a local bike shop for service.

Forums are good for many things, but not a substitute for a credible maintenance source.

You'll have to bite the bullet on this one I'm afraid.

2012-08-22 5:54 PM
in reply to: #4375801

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Sensei
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Subject: RE: Frustrated...

A 32?  Are you working on a MTB?  Long throw rear derailer?  Are the casettes compatable? 

Something strikes me as odd/different.  Sounds TO ME like you have way too much chain now going from the 32 to a 25 which doesn't keep the derailer in enough tension to stay off the spokes.

Did the old cassette have spacers?  Do they line up the same?

Like Tom said, this one sounds like it's a bit more complicated than a simple swap.  LBS is the best bet.



Edited by Kido 2012-08-22 6:03 PM
2012-08-22 6:04 PM
in reply to: #4375801

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McAllen
Subject: RE: Frustrated...
Tom Demerly. - 2012-08-22 5:50 PM

I think you do need to take this to a local bike shop for service.

Forums are good for many things, but not a substitute for a credible maintenance source.

You'll have to bite the bullet on this one I'm afraid.

 

was afraid I was gonna hear that :P I was expecting it but was hoping some bike guru was gonna be all pro and say something like "Well, grasshopper, the solution is simple..."

I'm still relatively new to servicing my own bike so yeah.

And no, its a road bike. Perfect for climbing mountains but I live on a pancake. It came with the bike when I ordered it.

2012-08-22 6:27 PM
in reply to: #4375758

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Elite
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Subject: RE: Frustrated...

The pulley hitting the cog is not a big deal, but is annoying. You have too much chain. Take some links out. If you do not have a chain tool, get one. You should have one anyway. Get a couple of pins to have a spare. Tape it to your tool to have it when you need it.

The "B" tension screw can adjust the tension a bit. It's the screw that touches the bike frame at the drop out.

There is zero reason to adjust your dérailleur changing cassettes, assuming all the spacers are correct. Are you sure your spacers are right?

If your dérailleur is going into your rim (most common) your hanger is bent. You can bend it back, but if it is aluminum then at some point it will break. I would strongly recommend you know you can get another one before you do anything. I could straighten mine out pretty good with an eye ball on my MTB which it was pretty common. A bent hanger is real frustrating if you do not notice it, because you can only adjust the derailer on one half of the cassette. The gears will be right on one side, but skip on the other. Get the other side right, then they skip on the original side. Of course a bike shop can do it for you correctly with an alignment tool. You can eye ball it from the back of the bike... the derailer cage should be perfectly straight up and down no matter where it is.

Be very careful adjusting your limit screws. It may look good at home, but get out and going and you shift into your drop out, or worse, you shift into your wheel and ruin that side of spokes requiring you to get your wheel rebuilt. That is of course assuming you removed that incredibly dorky protector on the inside of your cassette which no self respecting cyclist would be caught dead sporting. Don't ask how I learned that one.

Do you have instructions on how to adjust your derailer?



Edited by powerman 2012-08-22 6:30 PM
2012-08-22 6:30 PM
in reply to: #4375825

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Subject: RE: Frustrated...
odpaul7 - 2012-08-22 4:04 PM
Tom Demerly. - 2012-08-22 5:50 PM

I think you do need to take this to a local bike shop for service.

Forums are good for many things, but not a substitute for a credible maintenance source.

You'll have to bite the bullet on this one I'm afraid.

 

was afraid I was gonna hear that :P I was expecting it but was hoping some bike guru was gonna be all pro and say something like "Well, grasshopper, the solution is simple..."

I'm still relatively new to servicing my own bike so yeah.

And no, its a road bike. Perfect for climbing mountains but I live on a pancake. It came with the bike when I ordered it.

.The solution IS simple, but requires some special tools to check and may require a new part to fix (if itMs a replaceable hanger).


2012-08-22 6:57 PM
in reply to: #4375758

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Subject: RE: Frustrated...

Try this:

http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur

While I haven't experienced the issue you described, I have used these derailleur adjustment instructions multiple times with good results.

2012-08-22 7:41 PM
in reply to: #4375758

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Subject: RE: Frustrated...
I know how to do most basic maintenance stuff like i know how the limit screws are supposed to be adjusted, but the pulley is definitely at an angle... I guess I'll take it apart for one final look tomorrow and bring it to the LBS if i can't figure out what it is.

Closer look at the hangar, and check chain tension... That's about all i can think of now.

When i looked at the chain i did the big cog big cog test and there was no noticeable slack though. Same with little and little.
2012-08-22 10:09 PM
in reply to: #4375940

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Elite
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Subject: RE: Frustrated...

odpaul7 - 2012-08-22 6:41 PM I know how to do most basic maintenance stuff like i know how the limit screws are supposed to be adjusted, but the pulley is definitely at an angle... I guess I'll take it apart for one final look tomorrow and bring it to the LBS if i can't figure out what it is.

Closer look at the hangar, and check chain tension... That's about all i can think of now.

When i looked at the chain i did the big cog big cog test and there was no noticeable slack though. Same with little and little.

Can you post a pic?

The pulley being at an angle in what relation? As far as the posted instructions, or any others for that matter, the illustration is from the rear looking froward, and the dérailleur and cage is perfectly inline with the cogs top to bottom. Perfectly vertical. So are you saying it is not vertical, or something else? Even when you are on the bike, and you look down at the dérailleur, it should be perfectly straight up and down. You can see if it is off.

If you did big big little little then you should be good. No reason to shorten the chain for no reason.

2012-08-22 10:12 PM
in reply to: #4375758

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Subject: RE: Frustrated...
Looking from back to front the derailleur looks like this: /

Its bent inwards. I can post a pic tomorrow morning, but it'll probably be at the shop if i can't check out the rest.
2012-08-22 10:17 PM
in reply to: #4375801

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Subject: RE: Frustrated...
Tom Demerly. - 2012-08-22 5:50 PM

I think you do need to take this to a local bike shop for service.

Forums are good for many things, but not a substitute for a credible maintenance source.

You'll have to bite the bullet on this one I'm afraid.

X 2


2012-08-23 6:45 AM
in reply to: #4376121

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Subject: RE: Frustrated...
odpaul7 - 2012-08-22 11:12 PM

Looking from back to front the derailleur looks like this: /

Its bent inwards. I can post a pic tomorrow morning, but it'll probably be at the shop if i can't check out the rest.


Sounds like a bent derailleur hanger. Bet you that you had too much movement on the derailleur, it hit the spokes and got bent. It's not that difficult to replace the hanger in most cases (most manufacturers design their bikes with a replaceable hanger exactly for this reason... so the hanger bends, but the derailleur is saved).

Take it to a shop and have them take a look at it.

Also, why in the world did you go from a 11-32 to an 11-23?! That's a MASSIVE increase in gearing. The vast majority of people have no reason riding an 11-23.
2012-08-23 7:44 AM
in reply to: #4375758

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Subject: RE: Frustrated...

The other issue that you might be dealing with (in addition to chain now being too long) is that with a wide-range cassettes like a 11x32, or with triple chainring setups, a "long cage" derailleur is often used.   For more "traditional" cassettes like an 11x23, a "short cage" derailleur is typically used.  A rear derailleur spec may say something like "Total Capacity 33T", which tells you what setup this derailleur is best suited for.  I've lifted this good explanation from another forum:

The capacity is the maximum difference between your biggest rings (front and back) and your smallest rings.

That is, the minimum amount of chain you will needs is enough chain to cover the smallest ring at the front and the smallest cog at the back.

The maximum length of chain you need is enough to cover the biggest ring at the front and the biggest ring at the back.

The rear derailleur takes up the slack when changing from the maximum through to the minimum.

So the maximum capacity of the derailleur decides the biggest difference you can have between this minimum & maximum.

For example, if you're running a fairly standard setup = 12 - 27 on the back and 34/50 compact on the front, then the minimum gear is (12 + 34) = 46 and the maximum gear is (50+27) = 77. The difference between these is 31, which means the rear deraileur must have a max. capacity of at least 31T.

In general you should use a derailleur which is as close as possible to the capacity you require (i.e the shortest mech you can). The longer the derailleur, the more flex is introduced and the less reliable the shifting. Longer mechs are obviously also slightly heavier.

Bottom line... you should probably take it to a decent bike shop.

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