Derailleur search

1. There is no such thing as a triple-specific rear derailleur. Derailleurs are sold with specific numbers of gears on the cassette to shift (i.e. 9-speed, 10-speed or 11-speed, etc.). They are also sold with pulley cage lengths that are longer or shorter to wrap specific numbers of gear teeth maximums. A triple with close rage gearing can sometimes use a short cage derailleur and a triple with wide range gearing will need a medium length cage or a long cage to wrap all the chain needed to cover the larger tooth differences generated by the bigger gear ratio differences.

2. Derailleur throw ratios have to match those of the shift levers if the system is of the index type.

3. Can you specify the model of the Synapse Triple you have and the brand and model rear derailleur it came with when purchased and the gear combination of your chainrings and cassette as well as the number of gears on your cassette (say, something like 26-36-52 x 12-28 10-speed)?

A quick search shows Cannondale built the synapse in a Sora Triple and a Tiagra Triple and a 105 Triple in 2014. And it appears that they also built an Ultegra triple version. Gearing combinations were varied.

https://www.evanscycles.com/cannondale-synapse-8-sora-triple-2014-road-bike-EV199154
http://www.paulscycles.co.uk/m7b0s6p5460/CANNONDALE-SYNAPSE-ALLOY-TIAGRA-TRIPLE-2014
https://www.evanscycles.com/cannondale-synapse-carbon-5-105-triple-2014-road-bike-EV216598

The simaNO experts can then chime in with their knowledge of rear derailleurs compatible with your gearing and cable pull ratio.

4. Any local bike shop worth calling a bike shop would be able to get you a replacement rear derailleur which, due to the age of the bicycle, might possibly require you to update your shifters and possibly your front derailleur. In most cases a work around is available that only requires finding a compatible rear derailleur, but a little more information is needed before anyone can advise you as to what make and model might work.

Roamin Buffalo said:

i have a Cannondale Synapse 2014 I believe. It has a triple chainring. I managed to destroy the rear derailleur on a climb. I'm being told by my LBS that Cannondale no longer makes a triple for that bike and that the derailleur is no longer available. Does anyone have a work around for this? It's hard to believe the bike is history with only 7k miles.

Unless you misunderstood what whomever you spoke to at your LBS said to you, how can an LBS be so ignorant to suggest that "Cannondale no longer make a triple for that bike"?

[INDENT]Simply stated, Cannondale does not make derailleurs.[/INDENT]

YOU need to find a different LBS because, as my good friend CAMPYBOB suggests, if your bike has a Shimano SORA rear derailleur, then you can replace it with almost any Shimano rear derailleur which has a suitably long rear derailleur cage ... the exception would apparently be the latest-and-greatest 11-speed Shimano rear derailleurs and the pre-1994 (?) Shimano rear derailleurs.

[INDENT]It is not uncommon to use a Shimano MTB rear derailleur with many Shimano drivetrain configurations rather than a Shimano ROAD rear derailleur which has a "long" (GS) cage because it will allow a potentially wider range of gearing options.
[INDENT]
I recommend the older, non-Shadow Shimano XT rear derailleurs which have the standard pull vs. "Rapid Rise"/(reverse pull), first ...

Or, a Shimano SLX if you can live with the lack of a barrel adjuster (which can surely be retrofitted on, somehow!) on the Shadow-type rear derailleur.
[/INDENT][/INDENT]
If there isn't another LBS in your town AND/OR if you can DIY, then either buy a replacement rear derailleur from EXCEL, COLORADO CYCLIST, PERFORMANCE-NASHBAR, or eBAY ... just to name a few ...

[INDENT]There are other mail order retailers, of course, from whom you can buy components.[/INDENT]

Roamin Buffalo said:

i have a Cannondale Synapse 2014 I believe. It has a triple chainring. I managed to destroy the rear derailleur on a climb. I'm being told by my LBS that Cannondale no longer makes a triple for that bike and that the derailleur is no longer available. Does anyone have a work around for this? It's hard to believe the bike is history with only 7k miles.

Thanks in advance for your help.

alfeng said:

Unless you misunderstood what whomever you spoke to at your LBS said to you, how can an LBS be so ignorant to suggest that "Cannondale no longer make a triple for that bike"?

[INDENT]Simply stated, Cannondale does not make derailleurs.[/INDENT]

YOU need to find a different LBS because, as my good friend CAMPYBOB suggests, if your bike has a Shimano SORA rear derailleur, then you can replace it with almost any Shimano rear derailleur which has a suitably long rear derailleur cage ... the exception would apparently be the latest-and-greatest 11-speed Shimano rear derailleurs and the pre-1994 (?) Shimano rear derailleurs.

[INDENT]It is not uncommon to use a Shimano MTB rear derailleur with many Shimano drivetrain configurations rather than a Shimano ROAD rear derailleur which has a "long" (GS) cage because it will allow a potentially wider range of gearing options.
[INDENT]
I recommend the older, non-Shadow Shimano XT rear derailleurs which have the standard pull vs. "Rapid Rise"/(reverse pull), first ...

Or, a Shimano SLX if you can live with the lack of a barrel adjuster (which can surely be retrofitted on, somehow!) on the Shadow-type rear derailleur.
[/INDENT][/INDENT]
If there isn't another LBS in your town AND/OR if you can DIY, then either buy a replacement rear derailleur from EXCEL, COLORADO CYCLIST, PERFORMANCE-NASHBAR, or eBAY ... just to name a few ...

[INDENT]There are other mail order retailers, of course, from whom you can buy components.[/INDENT]

My LBS is a great guy and has been wonderful to me on bike purchases over the years, however, mechanically it is not worth much which is why I didn't take that as gospel. My bike has Shimano 105 components and I believe an 11 tooth cassette. I apologize for my ignorance, but as a gearhead my best ability is typing a thread on a forum site🙂 I will say he did try a MTB derailleur and that's what's on there, but the shifting is highly inadequate and it is almost impossible to get it into the big chainring.

11 tooth or 11 gears? Or both?
The difficulty getting onto the large chainring may be caused by a FRONT derailleur issue or a chain that is a link or more too short. The rear derailleur is not likely to be the cause of poor shifting up front.

Given that your bike is a 2014 model year and 105 you should be able, without too much searching, to find the exact replacement model for your trashed rear derailleur. The model number should be on the derailleur, itself, and failing that it is likely to be found in the specifications for your bike. Something like RD-5800-LG or RD-5800-S...once found, do a search for web retailers and compare the pictures to what you trashed.

Good luck!