ls0725

Hello,

I need advice. I have a Shimano 105 Model RD-5501 GS Long Cage Rear Derailleur but being used with a double crank. The Shimano tech specs says it can handle a 27T maximum largest rear gear.

I intend to install a 12-28T rear cassette, will it work? It's one tooth over max specs.

Any experiences/advice/theories would be appreciated. I dont wish to buy it and find out it wont work.

Thanks

bluenote157

It should work. I had an ultegra short cage (27t max) paired with 11-30 and it worked fine. I've done it with a 53/39 and a 50/34.

Chris_W

Whether it will work depends at least as much on the geometry of the derailleur hanger on your frame as on the derailleur model. Shimano spec's tend to be pretty conservative, so it's likely that you'll get the 5501 to work without any trouble - I've certainly made a 5600-series RD (which is also only officially rated up to 27 tooth cogs) to work with a 28-tooth cog, I don't think I've tried with a 5500-series. But again, a lot depends on your frame. Your chain length can also affect whether or not it will work, because that determines where the upper pulley ends up.

I'd recommend going ahead and buying the 12-28 cassette, there's a very high chance that you'll be able to make it work without any problems.

ls0725

really? yours is even way over the 27t max. well, that i reassuring. thanks.

Bekologist

I've run 11-32 with 105 derailleurs on a couple of bicycles and seen this setup on several other bikes.

ls0725

thank you, makes me feel confident. my chain seem to have a lot of slack and maybe it will work.

ls0725

thank you, it seems from all the replies, it should work.

JTGraphics

Should be fine check chain length and make sure upper wheel on RD isn't touching the 28t if so you will need to adjust B screw a little.

Barrettscv 

^^ this & I have been running an 11-32 without a problem.

ls0725

i will check that and adjust B-screw if it does touch. Thanks!

ls0725

32? wow, then 28 should be a breeze, thanks!

Nick9585

I just tried installing a 12-30 matched with a 105 5600 long cage and had issues getting into the largest cogs.

When I tightened the B-tension screw I could shift into the 28t cog, but that seemed to be as low a gear as it would go. I am also running a 53/39 up front.

Any recommendations? It seems from what I've read here than it might be possible.

Has anyone made this set-up (53/39, 12-30t, 5600 long cage DR) work?

Nick9585

I am trying to use a 12-30 with a 105 and I'm having trouble. What am I doing wrong?

HillRider

Well, you dredged up a 4 year old thread but your question is still valid. As noted above older 105, Ultegra, etc. road rear derailleurs were officially rated for a 27T maximum rear cog no matter what the cage length. Success with larger cogs depends a lot on the derailleur hanger's configuration so if your is rather short, the 30T cog won't clear even if the B-screw is fully tightened. A sort of kludge is to install a longer B-screw or reverse the current screw so it holds the derailleur further back. This may work but tends to compromise shifting to the smaller cogs.

The real cure in your case is to limit your cassette to a 28T maximum, replace your rear derailleur with a MTB model (9-speed or before, not 10-speed Dyna Sys), or a newer road rear derailleur rated for 32T like the Ultegra RD-6800.

Nick9585

Thanks. It's what I suspected, but I think I just needed to hear it. Also, for the suggestion, the Ultegra 6800 RD looks pretty sharp. It is something I am going to consider. Now my immediate question is do I return the cassette, or keep for future use.