tandemnh

I may need to replace the original Ultegra GS as I have switched to a 12-30 on my R2000. Would this be a suitable replacement to allow for the use of the 12x30?

Shimano Ultegra RD-6600 Rear Derailleur Long Cage EXC++

desertdork

yes

edit: yes, you can use 6500 or 6600 RD interchangeably. That's not to say it's guaranteed to work for a 30t cog, regardless, as this depends on your bike, too.

operator

If you're replacing because it won't clear the 30, then it won't make a difference.

tandemnh

So it sounds like I may need to go with a Shimano XT or XTR? What do you suggest?

motobecane69

I don't know why you don't trust me! lol, is your current RD the 6500 or the 6600? the one that I showed you in the pic on the other thread is a 6600 running a 32T PM me details on your problems, I once got a 34 tooth cog and a triple crank working with a vintage shortcage suntour honor RD. Your situation is WAY easier!

Al1943

Have you tried the search function? There have been several discussions on ways to make a road derailleur work with a 30 or even a 32. The most common technique is to replace the "B" screw with a longer one. There is no guarantee that this will work however.

tandemnh

It is the 6500 and I have screwed in the b screw all the way and flipped it all the way around. I am going to try and pick up a longer b screw today with a visit to my LBS.

motobecane69

okay. you could be one of the few that has the really short derailleur hanger which is preventing you getting sufficient clearance but at 30 teeth I would still think you would be okay.

cyccommute 

That would be the simplest solution. You can try to fiddle with a road rear derailer, adjusting and tweaking and messing with it. It might work...at some point and sometimes. Or you could just cut to the chase and use a mountain bike derailer. Depends on how much frustration you want to deal with.

shelbyfv

I would like to raise a forum etiquette issue. This is at least the third post you have started on essentially the same subject. Nothing wrong with asking the questions, it's an interesting problem and you've received good info on all the threads. However, if it was all in the same thread, it would help folks searching in the future, as well as saving potential responders time, as their response may have already been given by someone in one of the other threads. Now, regarding the actual mechanical issue. My experience is only with trying to use 32t cogs with GS rds. Some will work, some will not, it depends on the bike, not the rd. 6500 or 6600 will not matter. You can get a nice new LX rd for $30-$40 on ebay or Jenson if your GS doesn't work.

tandemnh

Great news, the fix is in!
I replaced the "b" screw from an old MTB Deore LX RD and a 10T sproket. That's all it took with a little adjustment and I am as good as gold. No click run through the gears great.
Thanks to all for the input. Great that I had the parts around the garage and did not have to drop a c note to replace the RD.
Now to go by that new computer with the money saved!