MTBaddict

I have a titanium road bike with which I have been quite pleased with one exception: I need lower gearing for hills.

The bike was originally all Ultegra 6600 (standard double, 10-speed). Before I even rode it for the first time, I changed the crank to the compact version (Ultegra 6650, 50/34). When it came time to replace the cassette, I switched to an Ultegra 6700 cassette (11-28) and the RD-6700 derailleur to get a slight bit lower gearing; however, it is not low enough.

I am looking for a compatible 32 or 34 tooth cassette and derailleur, if one exists. Otherwise, are there “standard” chainrings with fewer teeth that would work with my current setup?

Seems that, in the past people have been able to add Shimano mountain cassettes and derailleurs to Shimano road drive trains. Is such a mod possible here?

[One little added twist: After switching to the RD-6700 I found a Shimano chart that indicated that the shift levers I have (6600) are not compatible with the 6700. This may confirm an issue that I have been dealing with for some time. Seems the 6600 rear shifter was a bit of an odd duck in that it could allow downshifts of one, two, or three cogs at a time. The 6700 rear shifter is more standard in that it allow downshifts of only one or two cogs in a single shift. This is probably why I must use my trim level after every downshift to quiet the chain on the cassette. I would like to remedy this as well which likely means new brifters! $$$]

I started looking at 11-speed Shimano road drivetrains and they are very attractive because there are many more options offered; however, a change to an 11-speed system would require a new wheelset. At that point perhaps an entirely new bike may make more sense.

Help me if you can…

70sSanO

I don't have first hand experience, but I think you can run pre-Dyna-sys 10 speed road shifters with a 9 speed mountain bike rear derailleur. I think your 6600 is pre-Dyna-sys so something like an XT-750 should work. Then you can run a 34t.

I'm sure others will chime in with yay or nay.

John

fietsbob

Short cage?

If the difference in the chainrings is small 34-40? or a 1 by just the 34. then you can use a bigger low gear , with appropriate chain length..

because the wrap up length requirement, is less..

jwh20

There are many possible combination possible. I have a Felt Z5 that came equipped with Shimano 105 10-speed groupset and a 12-28 cassette. Pretty standard but I wanted to fit an 11-36 on it. Everyone said, "no way" but there are multiple videos and articles of people doing this both with a Roadlink extender or a RD swapout. I went the latter route and fitted a Deore XT 9-speed RD on the bike with a Shimano 11-36 cassette:



This works perfectly and did what I wanted it to do, allow me to keep riding up the mountain. The only modification I had to make was to drop by the local hardware store and get a longer "B" screw. The original one was not long enough.

I read that the newer Deore XT 10-speed will not with with the shifters due to a different ratio between the RD and the shifter. What I'm not sure of is will this RD work on an 11-speed system (I'm leaning toward that option) or will you need something different.

I'd do some searching and see where someone has done this already. It seems that they must have.

I also find it interesting that my other road bike, a Look 675 Light came with Ultegra 6800 11-speed and an 11-32 cassette from the factory. It's the medium-cage model. I've also heard that you can accomplish the larger cassette by buying the medium cage parts and replacing your short-cage.

redlude97

A couple things:

1. Your 6600 shifters are compatible with any 8/9/10 speed road RD and 8/9speed MTB RDs. Not sure what chart you saw but its incorrect or you were reading it wrong. Your left shifter doesn't have any trim so if it is noisy between shifts that is a setup issue likely. If you want to run an 11-34 then your best bet is to buy a 9 speed deore RD for <$30.

2. If you have a short cage 6700 that you bought recently it is more likely to be the revised version(6700a) which has a 30T max, look for it stamped on the cage

If it is the long(GS) version, it also officially supports a 30t. In both cases I would try an 11-32T as the majority of people get it to work with this size cassette since shimano is conservative with their specs. Size the chain using Big+Big.

3. If you decided you want to upgrade to 11 speed you can run the cs-hg800 11-34 cassette on a 10 speed freehub so you don't have to upgrade the wheelset, but only that cassette will work. The R8000 RD officially supports this size while some have gotten the 6800 RDs to work so purchase accordingly.

Davet

I’ve had great success running multiple bikes with 6700 shifters and 6700 short cage rear derailleurs, a 34/50 compact crank and 11/32 and 12/32 rear cassettes. Multiple bikes meaning: off the shelf bikes and custom bikes, made of steel or titanium or carbon. The brands included Specialized, Time, Look, Serotta, Spectrum to name a few. At least 8 different bikes. In each case that combo worked very well with just an adjustment of the B-screws turned in for clearance between the big cog and top jockey wheel. The ONLY caveat is that the chain must be cut so I could run the big/big combo. Otherwise no issues at all.

The 6700 rear derailleur geometry was changed to allow the use of larger cogs than earlier rear der generations: 6600/7800, etc.

rccardr 

Great advice here. Only thing I would add is that even earlier Deore RD's are compatible with your indexing system, all the way down to 6 speed ones. I'm running one of those on my Pelizzoli (9 speed 12-34) and another on Schwinderella (10 speed 11-34).

TimothyH

Are you sure?

What are the wheels?


-Tim-

MTBaddict

Wheelset: Ritchey Protocol WCS off center rim technology w/ Zero System Hub. These wheels are original to the bike and the bike was purchased before 11-speed drivetrains became available. I called Ritchey to see if an 11-speed freehub body was available for this wheel. Their answer was NO.

Interesting that redlude97 identified a specific 11-speed cassette that would work. I wonder, long term, what would be the availability of that one special cassette.

MTBaddict

Shimano 2010 compatibility.JPG

Currently I am using the ST-6600 shifters with the RD-6700 derailleur. The attached Shimano chart does not indicate that they are compatible. The RD-6700 is not the "a" model nor is stamped with "30t".

I do have a trim on my right shifter, for the front derailleur. The left shifter is for the rear. When I say I have to "trim" the rear derailleur after down shifting what I mean is that I have to tap the "B" lever to get proper alignment of jockey pulley-to-cog.

A+B Levers.JPG

MTBaddict

This is good news because I have spare 9-speed rear derailleurs XT, XTR, and SLX!

I believe that redlude97 also agrees that the 9-speed RD's will work with the 10-speed shifters.

Davet

Using a 9-SPD MTB rear der with 10-SPD STI shifters is extremely common, particularly with the touring crowd.

dsaul

I'm currently using a Shimano 10 speed road shifter with a Deore 9 speed rear derailleur with an 11/34 10 speed cassette and 50/34 crankset with no issues.

ksryder

I've used a 9 speed deore RD successfully with 10 speed (105) shifters.

But my suggestion would be to try the 11-32 cassette first, it might work work no other changes. Shimano is notorious for being overly conservative on their max cog capacity.

But then if it doesn't work you can get the Deore RD. Just make sure you get the non-Shadow/non-dyna sis type.

redlude97

You are reading that compatibility chart wrong. All the levers are compatible with all the RDs. Otherwise that would mean 6700 shifters are not compatible with 6700 RDs. If you have to hit the upshift lever to "trim" the RD then you have a cable tension set up issue that has nothing to do with compatibility.

MTBaddict

Yeah, I haven't been schooled in how to read these charts. Now I'm not sure what the separate boxes and connecting lines actually represent...

shelbyfv

Another 9 speed MTB RD with otherwise 10 speed road groups on multiple bikes. Works great. Have also used both 7800 and 7900 RDs with 32t cassettes w/o issues. If 32t is all you need, try it first with your existing RD.

shelbyfv

BTW, concerning your user name. It's unfortunate but another member has chosen a very similar name. His notoriety may have prevented some from posting in your thread. I realize you had the name first, but if I was in your position I would seek a change or at least post a disclaimer of some sort. JMO, of course.

MTBaddict

Is that a "Shadow" type derailleur shown in your picture? (ksryder cautioned against using a "Shadow" type derailleur.)

ksrdyer advised avoidance of Dyna-Sys series derailleurs; however, the cassettes that I am considering are CS-M771 which are Dyna-Sys. Would these Dyna-Sys cassettes have any issues with my proposed drivetrain? I intend to use a SRAM chain and a new M771 or M591 high normal rear derailleur. My OEM front chainrings were Ultegra but have since been replaced with SRAM equivalents.

Thanks for your advice and feedback!

jwh20

I'm not clear what is meant by "shadow" type. The one I used is:

Shimano XT RD-M772 9SPD Rear Derailleur SGS Long-Cage 9 Speed, Top-Normal

Shimano XT RD-M772 9SP Rear Derailleur | Jenson USA

ksryder

I stand corrected, shadow will work.

I was going off memory because I don't use this setup anymore and I got mixed up. But Dyna-sis (shimano's name for their clutch derailleurs) will not work.

The cassettes should be fine though, regardless of how they're labeled. They didn't change the cassette cog spacing, as far as I know.

Davet

As above, the 9-speed Shadow rear derailleurs work with 10-speed shifters. While operationally good the Shadows disadvantage is that it has no barrel adjuster on it, so it depends on cable adjustments being made somewhere else on the bike. Not a deal breaker but it could mean finicky tuning problems in some cases.

My wife uses a Shadow rear der on her otherwise equipped 6600 bike.

jwh20

That's true, the Deore XT (shadow??) does not have a barrel adjuster. But not needed on my bike at least because it has an adjuster on the downtube. But if needed there are after-market adjusters you can add.

Kimmo 

No...

bogydave

I changed for better climbing too
Went 50/34 with 11x34

Had to lengthen the chain

Thread here