# Can't shift to lowest cog on rear cassette



## Joe_Bike (Feb 9, 2008)

I just finished installing components to upgrade my bike to 10 speed. Shimano dura ace - brake/shift levers, front & rear derailleur, cassette & chain.

The problem I'm having is this; I can't get the chain to go to the smallest cog on the rear cassette. Even with the limit screw backed out as far as it will go and the cable slack. 

I have the cassette mounted on a mavic ksyrium elite wheel. I used the spacer that I used with the 9 speed cassette . The one that came with the new cassette was too narrow & wouldn't allow me to tighten up the cassette to the hub without having a lot of play.

Do I have to use the thinner spacer so that the cassette moves towards the spokes? If so what do I use to tighten the cassette?

Any ideas?

Thanks
Joe


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## Dinosaur (Jan 29, 2004)

Does it work under load? The reason I'm asking is my bike (Campy) won't shift to the small cog in my garage. When I'm riding it will.


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## TurboTurtle (Feb 4, 2004)

Joe_Bike said:


> I just finished installing components to upgrade my bike to 10 speed. Shimano dura ace - brake/shift levers, front & rear derailleur, cassette & chain.
> 
> The problem I'm having is this; I can't get the chain to go to the smallest cog on the rear cassette. Even with the limit screw backed out as far as it will go and the cable slack.
> 
> ...


I believe that you need both spacers since the 10-speed cassettte is more narrow than the 9-speed (thin spacer that came with cassette). The thick spacer came with the wheel and compensates for the wider campy-compatible cassette that Mavic makes.

It seems, though, that this will make your problem worse. I would start over with the cable disconnected and follow the procedure on the parktool.com website.

TF


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## Joe_Bike (Feb 9, 2008)

Dinosaur said:


> Does it work under load? The reason I'm asking is my bike (Campy) won't shift to the small cog in my garage. When I'm riding it will.



Dinosaur - I tried it out on my rollers & it still won't drop down.


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## Joe_Bike (Feb 9, 2008)

TurboTurtle said:


> I believe that you need both spacers since the 10-speed cassettte is more narrow than the 9-speed (thin spacer that came with cassette). The thick spacer came with the wheel and compensates for the wider campy-compatible cassette that Mavic makes.
> 
> It seems, though, that this will make your problem worse. I would start over with the cable disconnected and follow the procedure on the parktool.com website.
> 
> TF


TurboTurtle - if I use both spacers, it WILL make it worse. It's like I need a spacer to fit the other side!

With the cable disconnected & the adjustment screw backed almost out of the derailleur, the derailleur will still not line up with the small cog.....


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## bobski (Aug 12, 2005)

Joe_Bike said:


> The problem I'm having is this; I can't get the chain to go to the smallest cog on the rear cassette. *Even with the limit screw backed out as far as it will go and the cable slack. * ...
> 
> Thanks
> Joe


From this description, it may be the length of the cable housing loop to the derailleur. Sometimes, too short of a length may put just enough pressure to keep it from coming down to the smallest cog.


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## Joe_Bike (Feb 9, 2008)

bobski said:


> From this description, it may be the length of the cable housing loop to the derailleur. Sometimes, too short of a length may put just enough pressure to keep it from coming down to the smallest cog.



Bobski - you win the prize. 

Thanks a lot!!!!!!


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## cpark (Oct 13, 2004)

Joe_Bike said:


> Bobski - you win the prize.
> 
> Thanks a lot!!!!!!


Did it solve the problem?


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## Joe_Bike (Feb 9, 2008)

cpark said:


> Did it solve the problem?


Yes - it sure did. :thumbsup:


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## vespajg (Aug 24, 2007)

Another common reason for the inability to shift to the small cog is the set screw for the rear der. cable easily rotates to an incorrect position. If I remember correctly, you need to make sure the guiding tab on the set screw is facing the rear of the bike and not the wheel. Easy mistake to make. The diagram on the der. instructions is inverted, but shows the proper alignment.


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## bobski (Aug 12, 2005)

Glad you got it sorted out Joe_Bike



vespajg said:


> Another common reason for the inability to shift to the small cog is the set screw for the rear der. cable easily rotates to an incorrect position. If I remember correctly, you need to make sure the guiding tab on the set screw is facing the rear of the bike and not the wheel. Easy mistake to make. The diagram on the der. instructions is inverted, but shows the proper alignment.


If I understand you correctly, you are referring to the improper anchor point for the cable due to the rotated tab. I disagree. You should still be able to go to the smallest cog even with the wrong anchor point (assuming everything else is adjusted correctly). You would just get screwed up shifting across the range.


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## Joe_Bike (Feb 9, 2008)

TurboTurtle - you are correct in stating that I need both spacers. I did some research & found that Mavic makes - or did - make their own cassettes that were two mm larger than shimano 8 & 9 speed cassettes. Therefore, the 2mm spacer is required for 8 & 9 speed shimano cassettes on a mavic wheel. Also, the shimano 10 speed cassettes are 1mm smaller than the 8 & 9 speed cassettes. So you do need both spacers in my case.

So, with the longer cable housing (and a new cable since the other new one was cut too short for the longer housing) & both spacers, I'm up and riding.

Thanks everyone for all the help.


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## vespajg (Aug 24, 2007)

bobski said:


> Glad you got it sorted out Joe_Bike
> 
> 
> 
> If I understand you correctly, you are referring to the improper anchor point for the cable due to the rotated tab. I disagree. You should still be able to go to the smallest cog even with the wrong anchor point (assuming everything else is adjusted correctly). You would just get screwed up shifting across the range.


I originally got that advice off of this forum and confirmed it with a Shimano tech at a race. In any event, it worked for me. I had to set up a new rear der. quickly due to a crash and accidentally let the tab rotate. It would shift into the smallest cog on the stand, but labored quite a bit and was noisy after it finally made the jump. It also shifted fine throughout the other 9 cogs. Same thing on the road. 

I spent a long time trying the readjust it before I got that advice. Rotated the tab, slight tweak on the barrel adjuster, shifted perfectly. If I can find the thread that originally gave me that advice, I'll send it to you. Worked for them, too. 

It doesn't take much of an alteration in pull angle to make a der. not shift perfectly.

If you can get your's to shift well with the tab rotated, more power to you.


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## vespajg (Aug 24, 2007)

Here's the thread . . . 

http://forums.roadbikereview.com/showthread.php?t=90223&highlight=rear+derailleur+adjustment


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## bartmanthebiker (Jan 27, 2008)

vespajg said:


> Here's the thread . . .
> 
> http://forums.roadbikereview.com/showthread.php?t=90223&highlight=rear+derailleur+adjustment



You are EXACTLY right...I had the same problem and then made the change and presto...instant perfect shifting after some minor tweaking with the barrel adjuster!

This site is great for information!:thumbsup:


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## cxwrench (Nov 9, 2004)

bobski said:


> Glad you got it sorted out Joe_Bike
> 
> 
> 
> If I understand you correctly, you are referring to the improper anchor point for the cable due to the rotated tab. I disagree. You should still be able to go to the smallest cog even with the wrong anchor point (assuming everything else is adjusted correctly). You would just get screwed up shifting across the range.


no, what vespajg is referring to is the plate under the anchor bolt. if it rotates the tab will hit the body and keep the der from getting the chain down to the small cog. has nothing to do w/ the cable being in the wrong place, the tab actually hits the body of the der and won't let it move far enough.


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## bobski (Aug 12, 2005)

cxwrench said:


> no, what vespajg is referring to is the plate under the anchor bolt. if it rotates the tab will hit the body and keep the der from getting the chain down to the small cog. has nothing to do w/ the cable being in the wrong place, the tab actually hits the body of the der and won't let it move far enough.


Ahhh...thanks for the clarification. Makes sense.


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## rideorglide (Dec 3, 2005)

bobski said:


> From this description, it may be the length of the cable housing loop to the derailleur. Sometimes, too short of a length may put just enough pressure to keep it from coming down to the smallest cog.



Just passing by but wondered if the opposite is also true -- too much housing loop and a problem shifting to the big cog?


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## Bob the Wheelbuilder (May 5, 2004)

cxwrench said:


> no, what vespajg is referring to is the plate under the anchor bolt. if it rotates the tab will hit the body and keep the der from getting the chain down to the small cog. has nothing to do w/ the cable being in the wrong place, the tab actually hits the body of the der and won't let it move far enough.


This is worth a bump. thanks cxwrench

I had a rotated tab interfering with my shifting on just 1 of my two 10 speed cassettes, it was driving me crazy and I was beginning to wonder if the replaceable derailleur hanger had been machined improperly.

It's definitely something to think about if you are having trouble getting the chain to drop into the smallest cog with the cable slack and the derailleur stops properly adjusted.


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