UnfilteredDregs

Seems to be a lot of talk that the 6700-GS can indeed handle beyond a 28t cog...my bike even came with a 12-30 cog...I'm looking to open up my gear range a bit and it seems that the 6700 can easily accommodate a 32t cog, some have even claimed 34t...that's a stretch admittedly...

In the process of trying to verify this information I happened to notice "30t" inscribed on the derailleur cage...Is this indeed the "official," tooth capacity of the derailleur cage? The total capacity as per spec is 39t:

bigfred 

Interestingly, the "official" specification for the GS derailleur is still only a max. cog size of 28 teeth, per: https://techdocs.shimano.com/media/te...9830702204.PDF

It's ability to absorb additional link capacity was engineered around the use of road triples, not neccassarilly wide rear ratios.

However, as you and others have experienced, it's capable of handling more.

Davet

The 6700 rear derailleur will handle a 32t cog cassette *if* the chain is sized to the big-big method and the B-screw is turned in so the upper pulley doesn't bump the largest cog when in the lowest gear. I've done this on a variety of bikes. I've not tried a 34t cassette.

UnfilteredDregs

I'm wondering if I may have slack issues...on the smaller chainring... I'm going with a 48/32 crank...dropping from a 46/36..... What's the "Big-Big" method?

bigfred 

Two methods of determining correct chain length:

1. With chain on large ring and small cog, jockey pulley axles of rear derailleur cage should be vertical.

2. The Big/Big method. With chain on Big ring and Big Cog, stretch tight and add two links. Leaves you with a tortured rear deraillleur cage if cross chain Big/Big, but, provides for the greatest amount of chain take up when using wide ratios front and back.

You're moving from a ten tooth differential in front to a 16. The total "official" tooth capacity of the GS cage is 39 teeth. Leaving you with 23 teeth of capacity in the rear as long as the derailleur can be positioned to clear the cogs correctly. 11-32 shouldn't be too much of an issue. 11-34 would be the absolute max using the Big/Big and presuming your hanger and axle position are such that you can fine tune the B adjustment for cog clearance.

Have a read of that tech document I linked to.

tztag

> The 6700 rear derailleur will handle a 32t cog cassette

Confirmed this worked well on a Look 566, compact crankset, 6700 GS derailleur, 12-32 SRAM cassette. B screw about 3/4 of the way in, clearance is fine, no rattle on backpedal. Chain is sized small/small and then removed one additional link. Big/big would have let me remove one more link but wasn't necessary.

Tag

gsa103

There are 2 versions of the 6700 GS RD.

There's the RD-6700-GS which has a 28T max rear size (and works at 30T).
https://techdocs.shimano.com/media/te...9830753764.pdf
There's also the newer RD-6700A-GS which has an official 30T maximum size. Most likely you have the RD-6700A.

msanford

Hey I know this is super old conversation, but I am trying to convert my crossbike over to a gravel bike. I have the rd 6700 gs (derailleur) I'm not sure I see the "A" but I do think it is that (my eyes suck lately - really hard to read. On the cage is does say "30T". I would like to try to get to a 11-34 tooth cassette in order to have that 1:1 ratio. If I only have a 44-34 uprfront does that smaller big ring allow me to push capacity to a 34? Thanks

shelbyfv

Chain wrap and the ability to clear the 34T cog are different characteristics. The cog clearance also depends on your derailleur hanger configuration and is trial and error. I would suggest buying the 34T cassette you want and try it. If it doesn't work you can get a 9 speed MTB derailleur or use a hanger extension.

msanford

Thanks! When you say derailleur extension . . . like a wolftooth extension?

shelbyfv

yes

Barry2 

I did a bunch of research before I changed to a 6700 GS & 32T on my R3
Panic buy RD-6700-A GS for 12-30 ?
If tldr, go to post No 12

I also documented the 6700 / 6700A differences
Which RD-6700 tell difference RD-6700-A

enjoy, I hope this helps

Barry

ne46st

I've been using RD-5700 GS / RD-6700 GS with SRAM 1070 32t cassette for years. With SS I can go up to 30t no problem. If I remember right, when I did a similar research some time ago, someone explained the reason why Shimano only spec'd up to 30t cog is because that was (or is) their largest 10 speed road cassette at that time.