# Grrr...chain keeps coming off the 5.2!



## dave_gt (Jul 25, 2008)

The 5.2 is really a sweet ride and I am just now beginning to bond with it BUT, every ride over the last two weeks the chain comes off the crank! Took it back twice for cable adjustments and the last time was yesterday.

I was told it was as tight as the LBS could get it but it came off again today.

Wassup? 


dave


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## zac (Aug 5, 2005)

dave_gt said:


> The 5.2 is really a sweet ride and I am just now beginning to bond with it BUT, every ride over the last two weeks the chain comes off the crank! Took it back twice for cable adjustments and the last time was yesterday.
> 
> I was told it was as tight as the LBS could get it but it came off again today.
> 
> ...


is it throwing when going from large ring to small?

I must say that your LBS answer sounds a bit suspect though


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## dave_gt (Jul 25, 2008)

zac said:


> is it throwing when going from large ring to small?
> 
> I must say that your LBS answer sounds a bit suspect though



Hi, Zac...

Yes, it does seem to be going to the small ring. Just today I left the office at noon and after a quick 13 mile ride through our subdivision, I cruised up to stop in front of the house and lightly tapped to the small ring and it came right off again! No double shifting, no pressure uphill, nothing this time.

Driving me crazy.


Any ideas?


dave


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## Bocephus Jones II (Oct 7, 2004)

dave_gt said:


> Hi, Zac...
> 
> Yes, it does seem to be going to the small ring. Just today I left the office at noon and after a quick 13 mile ride through our subdivision, I cruised up to stop in front of the house and lightly tapped to the small ring and it came right off again! No double shifting, no pressure uphill, nothing this time.
> 
> ...


front der is faulty, damaged, not installed or not adjusted properly.


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## zac (Aug 5, 2005)

dave_gt said:


> Hi, Zac...
> 
> Yes, it does seem to be going to the small ring. Just today I left the office at noon and after a quick 13 mile ride through our subdivision, I cruised up to stop in front of the house and lightly tapped to the small ring and it came right off again! No double shifting, no pressure uphill, nothing this time.
> 
> ...


Absolutely. Chances are you just need to adjust your FD. I will assume that your chain is properly sized, and that should not be an issue. Also, just to eliminate the possibility, inspect your chainrings and from end-on and examine for any bent teeth.

Two things you can do: Visit the Park tool website and drill down to the front derailleur (SB: "derailer") and make adjustments as advised. Also the tech documents on the Shimano (I am assuming Ultegra) website are invaluable toward proper set up.

That being said. Look at your FD, from the top down, make sure it is not angled inboard toward the rear. This happens sometimes on a looser clamp when it gets kicked or something, and will cause you to throw the chain. It should be parallel to the rings. 
You will notice two screws on the top of the FD housing. These two screws control the limit of movement and are very easy to set. The inner screw controls the small ring limit, and the outer screw, naturally controls the big ring limit. You turn the screws in the direction you want the derailleur to go. For instance, clockwise, pushes the FD outboard; and counter-clockwise, inboard. You are interested in the left (inside) screw. Shift the FD into the small ring, and the RD into the biggest cog. You should have no more than 1mm, or so, distance between the inner plate and the chain. This is pretty close. Adjust the inner screw accordingly. Most likely, you need to turn the inner screw clockwise. Do it 1/4 to 1/2 turn at a time, and try until you are good.

Lastly I forgot to mention cable tension. Cable tension largely shouldn't be an issue here, as too loose will keep you from getting into the big ring, and too tight will keep you from getting back to the little ring, but your cable should be slightly slack, and not under tension, but just barely, when in the small ring.

HTH
zac


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## Tlaloc (May 12, 2005)

*Cross Chaining?*

If you shift all the way down to your largest (lowest) gear in back and still are on your largest chain ring in front you are doing what it referred to as "cross chaining". This should be avoided because it gives you a bad chain line and because the cage for the jockey wheels on the rear derailleur can barely deal with the chain length. If you shift into this combination and look at the rear derailleur you'll see what I mean. In addition if you shift into this combination and then shift onto the smaller front chainring you can drop your chain quite easily. For these reasons you should not use the two largest gears on your freehub with the larger chainring. When you need the lower gears, shift onto the smaller chain ring in front and then shift up two or three gears in back.

I've ridden 3,500 miles this year and dropped my chain once - when I was spacing out and did what I describe above.

Maybe this is the problem.


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## dave_gt (Jul 25, 2008)

Hi, guys...

thanks for the posts. I just got back from the LBS and the mechanic had a lot more than 1mm clearance on the inside der frame so he tightened it way up with just a hair of clearance. 

He is not used to the 5.2 BB and the stiffness, so he did not leave as much slack.

Hopefully this will do it. I will let you know this week as I ride.

Oh, and cross-chaining? Yeah, been guilty of that in the past but not this time...it was in the third largest cog not the top two and I was just coasting when the chain missed the small ring.

Here's hoping!:thumbsup: 


dave


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## JoeyBuck (Apr 2, 2008)

Go to the Park Tool web site and check out their "how to" section on repairs. 

If you are not up to tackling the adjustments yourself, at least the pictures will show you if the LBS is doing it right.


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## dave_gt (Jul 25, 2008)

Ah ha!

It worked...Zac, you were dead right...the inside screw needed a bit of adjustment as he had way too much clearance.

Not a single problem this time! 

Made the ride this afternoon so nice with the cooler temps and fall colors just starting.


best regards,

dave


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## zac (Aug 5, 2005)

Glad it worked out Dave.


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## dave_gt (Jul 25, 2008)

Wow...30 miles today and it is still shifting like it should!:thumbsup: 

Guess the mechanic at the LBS learned something new, huh?

Thanks everyone for their input.

dave


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## MANTEIGA (Sep 26, 2008)

dave_gt said:


> The 5.2 is really a sweet ride and I am just now beginning to bond with it BUT, every ride over the last two weeks the chain comes off the crank! Took it back twice for cable adjustments and the last time was yesterday.
> 
> I was told it was as tight as the LBS could get it but it came off again today.
> 
> ...


WOW... strange... 
This just started happening with my 5.2!?!? 
I wondered why myself, thank god for the wide gap to catch the chain on the 5.2's, or i
would have shredded the paint on my BB with enough pressure. Happened during an upshift - uphill yesturday.!? clicked out of my pedals just in time before i tipped over on my ass!?!?
If you come up with an answer let me know will ya. Still the best bike ever made though! :thumbsup:


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## MANTEIGA (Sep 26, 2008)

*what??*




dave_gt said:


> Ah ha!
> 
> It worked...Zac, you were dead right...the inside screw needed a bit of adjustment as he had way too much clearance.
> 
> ...



____________________________________

Sorry..... 
How did you fix it ??

Your vertical clearance was too high!?  
Or was it the clearance to the left of the chain. I assume you just adjusted the
derailleur screw to limit the gap??
let me know if it happens again. This bike is so amazing, it's easy to develop an OCD complex when things aren't right.


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## dave_gt (Jul 25, 2008)

Hey,

Just take the bike back to the LBS and get them to tighten up the adjustments. Seems my mechanic is not used to such a stiff frame and bracket that he could not believe how close he could adjust the front der. It must be because he adjusts for a little flex and that allows the chain to come off.:idea: 

Now, it works perfectly!

Good luck,

dave


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## 08Madone5.2 (Dec 25, 2007)

Tlaloc said:


> If you shift all the way down to your largest (lowest) gear in back and still are on your largest chain ring in front you are doing what it referred to as "cross chaining". This should be avoided because it gives you a bad chain line and because the cage for the jockey wheels on the rear derailleur can barely deal with the chain length. If you shift into this combination and look at the rear derailleur you'll see what I mean. In addition if you shift into this combination and then shift onto the smaller front chainring you can drop your chain quite easily. For these reasons you should not use the two largest gears on your freehub with the larger chainring. When you need the lower gears, shift onto the smaller chain ring in front and then shift up two or three gears in back.
> 
> I've ridden 3,500 miles this year and dropped my chain once - when I was spacing out and did what I describe above.
> 
> Maybe this is the problem.


I did exactly that on my ride yesterday. First day on the bike in 2 weeks as I have been unable to ride due to commitments. Was in the big ring in front and middle ring in back. Was approaching a big hill, shifted to the lowest (largest ring) gear in back, then went to drop the front to the smaller ring and presto, chain was off! Was able to move into a smaller cog in back and shift up to the small ring in front while still on the bike, so no greasy hands. First time I've dropped all year. My fault!


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