Question to you masters of compact cranks...

[Kevan]

One of my riding pals was having problems with her bike yesterday with the chain dropping off the rings. Here's what she has to say:

As re. my bike set up: In the front I have a 35/50, rear cassette is 11/25, Shimano Ultegra 10 speed. Also, my wheels are 650's [ Comment: her bike is a small frame], which might be relevant. I can go for a couple weeks with no problem, then all of a sudden, I start dropping chains again. I have had problems moving in both directions, but yesterday, both drops occurred when shifting from the large to the small chain ring. Generally speaking, I seem to have FAR more problems with the Giant/compact than when I am on the Calfee (39/53 in front; 11/25 or 27 rear). It's getting kind of annoying, so if you turn up any ideas on it I would certainly appreciate it!

So what do you think? She's using a good shop for service, but this problem persists. What is the best make/model front derailleur for this application? What do you think the solution might be?

Her bike's size is 2XS: http://www.giant-bicycle.com/us/catalogue_popup.asp?sPageID=popup&popuptype=geometry-image&modelid=11536

Off the web, I offer this: http://www.bikeschool.com/technical-board/messages/10711.htm

[72gmc]

I think her solution might be a 39/53 crank and a medium cage derailleur with a 13-29 cassette...

I'm pretty much turned off of compact cranks after reading so many discussions about them on this forum.

[hillrider]

FSA (http://www.fullspeedahead.com) made the C-16 model
and IRD (http://www.interlocracing.co) also makes compact front derrailleur

http://www.rivendellbicycles.com/webalog/shifters_derailleurs/17121.html
http://www.interlocracing.com/cdfrtder.html

Also read this from Velonews magazine tech department:

Dear Lennard,
I'm building up a new road bike with a compact front crank and want the best front shifting possible while using Shimano STI shifters. The problem is that Shimano has yet to release a compact front derailleur optimized for these systems.

It looks to me that the compact front derailleurs from Campagnolo seem to be quite specific to their drivetrain. What would the drawbacks be and would there be any compatibility issues with using a Campagnolo compact front derailleur with an otherwise Shimano drivetrain (with the exception of the compact crankset of course). Or would you recommend sticking with the after-market (FSA, IRD, etc.) compact front derailleurs?
Jonathan

Dear Jonathan,
My experience is that the Campy CT compact front derailleur only works with Campy compact chainrings. With FSA rings, for example, it seems to just mash the chain right into the side of the big ring without it climbing up onto the teeth. I would use a standard double front derailleur, including Campy. It works fine with FSA 34-50 rings. I even have this setup on one of my bikes. I certainly would not recommend using a Campy CT front derailleur with anything other than a Campy CT crank. The IRD and FSA will work very nicely as well.

As far as I know, Shimano has no plans of releasing a compact front derailleur optimized for these systems as you seem to be hoping for. Shimano's new compact crank has chainrings optimized to work with its standard double front derailleurs.
Lennard

[Ken Robb]

my Legend has FSA compact w/50-34 shifted flawlessly by 10 DA brifters and dbl derailer.

Hampsten has Ritchey 50-34 shifter equally well by 9 spd Campy dble derailer and brifters. Nothing wrong with compacts in my experience.

I will make an unschooled guess/generalization here: bikes with longer chainstays are less finicky about shifting than bikes with short chainstays and that may be due to less acute chain angles with longer stays.

I say this because my triple also shift beautifully and I've heard many complaints here and elsewhere that triples never shift as well as doubles.

[Bruce K]

Kevan;

I am running both an FSA 50/36 on my Ottrott and a 50/34 on my Concours with Shimano 10 speed (D-A and Ultegra).

Both bikes are using the old 9 speed derailleur without issues.

I would certainly recommend a compact specific front derailleur if she is having issues and does not already have one but generally a good mechanic can make the necessary adjustemnts.

As a safety precaution, both bikes have 3rd Eye Chainwatchers mounted on the seat tube.

If I've ever dropped a chain to the inside, I've never noticed.

BK

[Julia Hampsten]

As a safety precaution, both bikes have 3rd Eye Chainwatchers mounted on the seat tube.

If I've ever dropped a chain to the inside, I've never noticed.

BK

My small (50cm tt) Hampsten was dropping the chain to the inside (FSA compact crank). The 3rd Eye or "sharkstooth" Steve put on fixed it, no more problems. Should be commonly available at bikeshops.

Julia

[Serotta PETE]

I have over 5K miles on one just as below with no problems. This sounds like a question for Mr. Spoke. He replaced a chain 3k miles ago and no problems with it, (standard front Der)>

I also have a campy compaq with campy compaq front der but it only has about 1k miles on it but again no problems.

[QUOTE=Ken Robb]my Legend has FSA compact w/50-34 shifted flawlessly by 10 DA brifters and dbl derailer.

QUOTE]

[jahah]

I was having some problems with my FSA compact using Shimano Dura Ace. I recently changed to the Shimano compact crank (ultegra quality with external BB). Shifting is perfect. It only makes sense that shimano would design the crank to work well with their standard front ders.

Jim

[Julia Hampsten]

I was having some problems with my FSA compact using Shimano Dura Ace. I recently changed to the Shimano compact crank (ultegra quality with external BB). Shifting is perfect. It only makes sense that shimano would design the crank to work well with their standard front ders.

Jim

That's interesting, I'm using a Shimano (Dura-Ace) derailleur with the FSA crank too. . .your solution makes sense.

JH

[Grant McLean]

Some shifting problems can be like plane crashes... no single factor is the cause,
but several things happening at the same time, and it goes all wrong.

Some thoughts:
Have the derailleurs been adjusted? When she says sometimes there's no problem,
and then later has a problem, does this mean that she's not tried adjusting
the limit screws yet? If she said adjustments have already been tried,
I'd be more concerned that it's something else.

The shorter chainstays on her bike will be a contributing factor to dropping
the chain, but if the only time she is experiencing a chain drop is during
"shifting", then it is most likely a set up of the derailleur issue. That said,
I prefer to use the FSA compact front derailleur with non shimano cranks.

g

[Ken Robb]

I'm not sure but I might have heard that FSA made some mods to their compact cranks and/or rings after having some problems shifting with their first prodiuction run.. Maybe I was dreaming but then new ones work great.

[quehill]

I've used a bunch of different compact cranksets with a bunch of different front derailleurs on a bunch of different bikes. Let's see if I can remember all of the combinations (all cranks below were 50-34)…

FSA crank with Ultegra 9 FD
Shifted smoothly but lots of chain drop

FSA crank with IRD compact FD
Shifting is less crisp, but there's noticeably less chain drop... still more than I would like though.

Truvativ (Bontrager branded) crank with FSA compact FD
Indistinguishable from the FSA crank & IRD FD combination above.

Campy (Centaur CT Carbon) Crank with IRD compact FD
No dropped chains, but the shift from 34 -> 50 was either slow or impossible.

Campy (Centaur CT Carbon) Crank with Chorus CT FD
Flawless. Quick shifting and no dropped chains.

YMMV, but I think the best shifting you’re going to get out of an FSA compact crankset or the like is adequate. If you want actively good front shifting on a compact setup, you need to go full Campy (or, based on what I've heard from folks who use the new Shimano compact crank, full Shimano.)

[velodadi]

I have a Fierte IT with Campy chorus compact 10 gruppo. It worked flawlessly for 5 months. Then it would drop the chain on the upshift to the big ring.

I took it in to my LBS and after a tune-up it once again works fine. It appears some cable slack can really mess things up. It is definitely more sensitive than a standard 53/39 set up.

V

[atmo]

of all the compact cranks i know,
stevep is the master atmo.

[jeffg]

shift very well, though the Campy shifts best ...

As a mountain double, they are great.

[Dan Le foot]

I'm using a 10 speed Shamano compact crank with Ulterga 9 speed components. Simply lowered the FD.
LBS slipped a couple of small spacers between the chain rings to account for the wider 9 speed chain.
Works fine.

[Kevan]

My pal Nancy asks that I foward her message. Here it is:

WOW! Kevan, I would appreciate you posting this for me, thanking everyone for all their comments on this. I've just been muddling along dealing with it, fearing deep inside that I am just a terminally incompetent shifter. A new crankset or FD will be far less expensive than psychotherapy, and more fun to procure as well. (can you even get a carbon fiber therapist?)

I do indeed have FSA cranks with Shimano Ultegra, and of course, as someone has observed, Shimano does like us all to use Shimano for everything and seems to do a pretty good job in making it difficult for the rebels among us. Despite the mixed experiences of those using mixed mfr. combinations of cranks and shifters, I think I am inclined to try a more compatible set up as my next move, either going to the compact specific derailleur or the Shimano cranks. I am sure it isn't a matter of simply adjusting the limit screws, which I have done many times. The post from "quehill" describing his experience with an FSA crank with Ultegra 9 FD setup "Shifted smoothly but lots of chain drop" is more to the point. It isn't the shifting, it's the dropping. I do indeed have shorter chainstays due to my small bike, a fact that has been suggested by my LBS as a contributing factor, but, of course, I can't do anything about that unless I get a bigger bike (is it too late to grow?). A chain watcher is also a good suggestion; of course, it will only help when the drop is to the inside, but half is better than none. I really appreciate everyone's suggestions. I like the gearing the compact provides, and have thought about changing over my other bike, but these chain drop issues is making me reluctant to do so.

Nancy

Okay Nancy, here it is, but you need to join us for your next posting. (She's a lurker, you know?)