Bicycle Mechanics - What derailleur is this?

Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.



PDA

View Full Version : What derailleur is this?

mynameistaken
07-29-11, 08:02 PM
This is supposed to be a 105 5700. However it doesn't look like the ones on Shimano's website. I don't see any markings on it either. Can someone please verify that this is a 105?

http://farm7.static.flickr.com/6003/5988899833_8e7d6d0fb4_b.jpg

desertdork
07-29-11, 08:09 PM
Possibly a R770. The backside of the inner cage plate should have the model # on it, e.g. FD-R770.

The R770 & R773 FDs were designed for 10-sp drivetrains in conjunction with Shimano's SL-R770 flat bar shifters. Is this a hybrid bike?
mynameistaken
07-29-11, 08:14 PM
Yes its a hybrid bike, and yes I looked where you said and it is a 770. Will a 105 work with flatbar shifters?

desertdork
07-29-11, 08:24 PM
I've not tried those 770 shifters with a 105 derailleur, but the claim by Shimano is that the two will be incompatible. Does your FD-R770 need to be replaced?...or is this a type of upgrade? I ask because the 770 is a high quality derailleur.
mynameistaken
07-29-11, 08:33 PM
Actually you are right again! The 770 does at least cost more than the 105 a few places I checked. The reason I asked is because the bike I just purchased was advertised to come with the 105 5700. It works fine so I will leave well enough alone.

Thanks!!!!!
JiveTurkey
07-29-11, 08:51 PM
That FD is a flat-bar road FD. It allows you to use flat-bar/MTB front shifter with larger road chainrings. Don't replace it with a regular road FD, like the 105, or its cable-pull ratio won't match to your shifter.
desertdork
07-29-11, 08:51 PM
FWIW, in your comparison, you shouldn't really judge the quality difference by the item price. I suspect that Shimano sells countless more 5700 FDs than R770 FDs, and either a higher price or lower profit will come with the smaller production. Regardless, the R770 I had was functionally and cosmetically equal to my Ultegra.