sheps58

I have a Specialized Tarmac Pro Dura ACE 10 speed with a 50 34 FSA compact crank. I have a 12 27 cassette.
My front derailleur is Ultegra . My problem is I keep throwing my chain over the small ring. What can I do?

botto 

mixed message.

Tequila Joe

1. Adjust the FD limit screw
2. Don;t shift rear & front deraileurs at the same time.

80vette

https://techdocs.shimano.com/media/te...9830611838.pdf

Part 1 of the SIS adjustment
You need to adjust the limit screw so it is not throwing the chain so far.
Turn the inside screw clockwise.

AEO

sacrifice a lamb to the cycling gods, that'll fix it.

actually, just get a dog fang after you adjust the limit screws on the FD.

KevinF

As others have said, the limit screws of your derailleur probably need adjusting. When the chain is in the 34x27 combo the chain needs to be really close to the derailleur cage (left side of the chain close to the left side of the derailleur cage).

I think Shimano and Campy have both come out with front derailleur's that are supposed to work equally well with standard and compact doubles; I don't have any experience with these though. There are compact-specific front derailleur's (which is what I use) out there that better match the sharper curvature of compact chainrings. If you're using a standard front derailleur on a compact crank then you really need to get the derailleur positioned precisely.

cuski

That doesn't always work. An innocent virgin, on the other hand....

Dagamon

There's a little plastic jobbie that you can attach to your frame that prevents the chain being thrown off. Dunno what it's called.

pedalada

dog fangs and third eyes won't work on some of the new CF frames with outlandish tube shapes and sizes near the BB. As far as I could tell the only thing that makes the FSA compact FD different from any other FD is the shape of its cage, Shimano claims the standard DA or Ultegra will work with their compacts. I had good luck with the FSA FD when I had a bike with an FSA compact crank, others have not. Your symptoms sound more like a limit adjustment issue.

songfta

I run compacts on my two road bikes, one using Campy derailleurs, the other Shimano. I've not had a problem with using a non-compact-specific front mech on either setup: the Campy is a 2005-vintage Chorus, shifting on a SRAM Rival compact (34-50); the Shimano is a 2007 Ultegra mech shifting on a Truvativ Roleur Carbon compact (36-50). Both shift fine, no worries.

With the Campy setup, I had to do a bit more fine-tuning because of the bigger difference between chainring sizes, which made fine-tuning the limit screws and derailleur alignment a bit of a challenge. For a while, I was throwing the chain off the outside of the big ring when in the small cogs in the back; now all is well and shifting fine.

Mr. Beanz

I've met plenty of riders with shifting problems on a compact double. Should have gone with a triple for more precise shifting!

Retro Grouch 

And if that doesn't work, try this: Back off the HIGH limit screw about 1/8 turn. My bet is that'll fix it.

A lot of guys set the high limit screw by shifting into the highest gear position and tightening the screw against the derailleur. When you do it that way it can cause the derailleur to bind against the limit screw. When it does that it makes the front derailleur hang up mpmentarily and throw the chain hard across the small chainring when it finally lets go.

Psimet2001 

But where in the world could we find a virgin? Especially on Bike Forums?




- adjustment first. FD second. All else fails - dog fang or third eye chain catcher.

Welcome to compact shifting. Some setups can be prone to this even with the correct adjustment.

Pugsly

Doesn't FSA recommend going to a compact specific front derailleur? I thought that only the Shimano compact could use the stock one but could be mistaken (or mislead by Shimano marketing literature)

Psimet2001 

As a generalization this is somewhat correct, but many will assure you that adequate shifting performance can be achieved on all compacts with a standard double.

I have asserted before though that Shimano's own marketing for the release of the R700 mentioned the fact that with it's shift ramps it was designed specifically to be used with the standard Ultegra FD.

As mentioned earlier the only difference is cage design.

Campy did not change the design of their compacts to be able to shift well with a standard FD they standardized their FD's to a happy medium that will work on both for model year 2008 and forward.

BTW - when I saw you quote "I have a FSA Compact" I figured the reply was going to be "Well that's your problem"

Pugsly

I'm still trying to understand how "Dura ACE" becomes FSA and Ultegra components. My bike is Dura Ace, but only because all the little shiny bits say Dura Ace on them. Except for the crank which says Shimano because I run the compact.

s.peterson

I doubt the Dog Fang will fit on your frame. I have an '05 Tarmac, and the tube shape on the seat tube above the bottom bracket will not allow it to clamp on.

brianappleby

i had the same problem about 2000 miles into my compact FSA/Ultegra FD bike. You have a few options. You can adjust all you want, but I was never able to get it perfect on mine. That said:

Buy a compact-specific FD from FSA.
Buy a compact crank from Shimano (R-700, etc)
Buy a Standard (non-compact crank from anybody)

Any of these should do it.

banerjek

If adjusting the limit screw doesn't solve the problem, was the FD lowered when it was installed? If not, this needs to be done. Also, if the FD has been slightly twisted, you could experience the symptoms you are -- turning just slightly could solve it.

You do not need a compact specific FD. Since you're throwing over the small ring, the limit screw sounds like the most likely problem.

Campag4life

Relatively common with a 16 tooth diff from big to small front ring. Issue is, if you set up the front derailleur to allow max cross chain without rattle, this is generally too loose to permit a quick front shift from big to small. So you do need to tighten the small ring limit screw and perhaps a bit tighter than what permits max cross chain when running small/small which you shouldn't run away.
HTH.